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1185 Cards in this Set

  • Front
  • Back
What is a plasmid?
A segment of bacterial DNA that can contain genes for resistance or toxin production

2010-138
What kind of genetic information is stored in the bacterial plasmid?
Genes for antibiotic resistance, enzymes, and toxins

2010-138
What is the function of the bacterial capsule?
It is antiphagocytic

2010-138
_____ are bacterial structures that mediate adherence to the host cell surface and are composed of glycoprotein.
Fimbriae (pili)

2010-138
What kinds of enzymes are in the periplasmic space?
Hydrolytic enzymes (eg, β-lactamases)

2010-138
What two subunits do bacterial ribosomes contain?
30S and 50S subunits

2010-138
Which bacterium has a nonpolysaccharide capsule?
Bacillus anthracis (which has D-glutamate)

2010-138
What is the chemical composition of most bacterial capsules?
Polysaccharide

2010-138
What bacterial structure provides resistance to desiccation, heat, and chemicals?
Spores

2010-138
What is the function of the bacterial plasma membrane?
It is the site of oxidative and transport enzymes

2010-138
What structure aids bacteria in adhering to foreign objects, such as indwelling catheters?
Glycocalyx

2010-138
What are the two functions of the peptidoglycan layer in bacteria?
Rigid support and protection against osmotic damage

2010-138
What bacterial structure establishes attachment between two bacteria during conjugation?
Sex pili

2010-138
What is the major surface antigen in gram-negative bacteria?
Outer membrane (polysaccharide component of lipopolysaccharide)

2010-138
_____ are bacterial structures that provide motility and are composed of protein.
Flagella

2010-138
What structure in gram-negative bacteria induces tumor necrosis factor and interleukin-1?
The lipid A component of lipopolysaccharide

2010-138
What is the chemical composition of the bacterial plasma membrane?
The lipoprotein bilayer

2010-138
What is the chemical composition of glycocalyx?
Polysaccharide

2010-138
Which two cytokines does teichoic acid induce?
Tumor necrosis factor and interleukin-1

2010-138
What is the chemical composition of the bacterial peptidoglycan layer?
A sugar backbone with cross-linked peptide side chains

2010-138
What is the major surface antigen in gram-positive bacteria?
Cell wall

2010-138
Where is endotoxin (lipopolysaccharide) located in gram-negative bacteria?
In the outer membrane

2010-138
What is the space between the cytoplasmic membrane and the outer membrane in gram-negative bacteria called?
The periplasm

2010-138
What is the chemical composition of a spore?
Keratin-like coat and dipicolinic acid

2010-138
What structures are unique to gram-negative organisms?
Outer membrane (endotoxin/lipopolysaccharide), β-lactamases in periplasmic space

2010-138
What structure is unique to gram-positive organisms?
Teichoic acid

2010-138
What is between the inner cytoplasmic and outer membranes in gram-negative organisms?
Periplasmic space (the location of many enzymes, including β-lactamases)

2010-138
What is between the capsule and peptidoglycan layers in gram-negative organisms?
The outer membrane (which contains endotoxin/lipopolysaccharide)

2010-138
What is the difference between the peptidoglycan layer of gram-positive organisms and that of gram-negative organisms?
The peptidoglycan layer in gram-positive bacteria is much thicker than that of gram-negative bacteria

2010-138
What structures are common to both gram-positive and gram-negative bacteria?
Flagellum, pilus, capsule, peptidoglycan, and cytoplasmic membrane

2010-138
Listeria is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram positive bacillus

2010-139
Gardnerella is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus (gram staining can be variable)

2010-139
Name three types of spirochetes.
Leptospira, Borrelia, Treponema

2010-139
What unique staining characteristic do Mycobacterium and Nocardia possess?
Mycobacterium and Nocardia are acid fast

2010-139
Francisella is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus

2010-139
Bordatella is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus

2010-139
Legionella is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus

2010-139
Brucella is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus

2010-139
What are the major gram negative cocci?
Neisseria

2010-139
Pasteurella is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus

2010-139
Yersinia is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus

2010-139
Corynebacterium is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram positive bacillus

2010-139
Haemophilus is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus

2010-139
What are the two types of gram positive branching, filamentous bacteria?
Actinomyces and Nocardia

2010-139
Bartonella is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus

2010-139
Clostridium is a _____ (gram positive/gram negative) _____ (coccus/bacillus) .
Gram positive bacillus

2010-139
Name the two major gram positive cocci.
Staphyloccus and Streptococcus

2010-139
What type of bacteria contain mycolic acid in their cell walls and have high lipid content?
Mycobacteria

2010-139
What type of bacteria contains sterols but lacks cell walls?
Mycoplasma

2010-139
Mycobacteria can be visualized by acid-fast stain as a result of what characteristic?
High lipid content in the cell wall

2010-140
Name six organisms that do not stain well by Gram stain.
Treponema, Rickettsia, Mycobacteria, Mycoplasma, Legionella pneumophila, and Chlamydia Remember: These rascals may microscopically lack color

2010-140
Which primarily intracellular organism does not Gram stain well but can be seen with silver stain?
Legionella pneumophilia

2010-140
Name three predominantly intracellular parasites that do not Gram stain well.
Rickettsia, Legionella, and Chlamydia

2010-140
Name two methods used for visualizing treponemes.
Dark field microscopy and fluorescent antibody staining

2010-140
What is the reason that Mycoplasma do not Gram stain?
It does not have a cell wall

2010-140
Periodic acid-Schiff (PAS) staining is used to stain what types of metabolic substances?
Glycogen and mucopolysaccharides (PASs the sugar)

2010-140
Ziehl-Neelsen stain is used to stain what organisms?
Acid-fast bacteria

2010-140
India ink and mucicarmine can be used to visualize what pathogen?
Cryptococcus neoformans

2010-140
True or False: Periodic acid-Schiff staining is used to diagnose Whipple's disease.
True

2010-140
Silver stain is used to stain what organisms?
Pneumocystis and Legionella

2010-140
Borrelia, Plasmodium, Trypanosoma, and Chlamydia species can be visualized using what type of stain?
Giemsa stain

2010-140
Neisseria gonorrhoeae requires what medium to grow?
Thayer-Martin (VPN) media

2010-140
Bordetella pertussis requires what medium to grow?
Bordet-Gengou (potato) agar

2010-140
Fungi require what medium to grow?
Sabouraud's agar

2010-140
Legionella requires what medium to grow?
Charcoal yeast extract agar buffered with cysteine

2010-140
In what medium can Mycoplasma pneumoniae grow?
Eaton's agar

2010-140
What is the appearance of Escherichia coli when it is grown on eosin-methylene blue agar?
Colonies with blue-black color and metallic sheen

2010-140
Lactose-fermenting enterics on MacConkey's agar grow colonies that are what color?
Pink

2010-140
Mycobacterium tuberculosis requires what medium to grow?
Löwenstein-Jensen agar

2010-140
Which media are used to culture Corynebacterium diphtheriae?
Tellurite plate, Loeffler's medium

2010-140
Escherichia coli can grow on what medium other than MacConkey's agar?
Eosin-methylene blue agar

2010-140
Haemophilus influenzae requires what medium to grow?
Chocolate agar with factors V (NAD) and X (hematin)

2010-140
Why does Mycobacterium tuberculosis have a predilection for the apices of the lung?
The apices of the lung have the highest partial pressure of oxygen

2010-140
Which aerobe is commonly associated with burn wound infections, nosocomial pneumonia, and pneumonias in patients with cystic fibrosis?
Pseudomonas aeruginosa (remember: Pseudomonas AERuginosa is an AERobe)

2010-140
Which bacteria are obligate aerobes?
They are all obligate aerobes (remember: Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis, and Bacillus = Nagging Pests Must Breathe)

2010-140
The lack of which enzymes makes obligate anaerobes susceptible to oxidative damage?
Catalase and/or superoxide dismutase

2010-141
What are characteristics of anaerobe infections in tissue?
They are generally foul smelling and difficult to culture and produce carbon dioxide and hydrogen gas

2010-141
What do Clostridium, Bacteroides, and Actinomyces have in common?
They are obligate anaerobes (remember, they Cannot Breathe Air)

2010-141
Why are aminoglycosides ineffective against anaerobes?
AminOglycosides require Oxygen to enter a bacterial cell

2010-141
Which bacteria are facultative, intracellular organisms?
Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, and Yersinia (remember: Some Nasty Bugs May Live FacultativeLy)

2010-141
Which organisms are obligate intracellular organisms that cannot make their own ATP?
Rickettsia and Chlamydia (remember: Stay inside (cells) when it is Really Cold)

2010-141
Name five encapsulated bacteria.
Klebsiella pneumoniae, Salmonella, Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis (remember: Kapsules Shield SHiN)

2010-141
In the synthesis of vaccines against encapsulated bacteria, conjugation of polysaccharides with protein has what effect on the body's immune response?
Increases immunogenicity and T-cell-dependent response

2010-141
A polysaccharide capsule adds virulence by what mechanism?
Preventing phagocytosis

2010-141
What part of the bacteria is used as antigen in vaccines against Streptococcus pneumoniae, Haemophilus influenzae type B, and Neisseria meningitidis?
The capsule

2010-141
Which test is used to see if an organism is encapsulated?
The Quellung reaction, in which the capsule swells (remember: Quelling = capsular swellung)

2010-141
Which four bacteria are urease-positive?
Helicobacter pylori, Proteus, Klebsiella, and Ureaplasma (remember: Particular Kinds Have Urease

2010-141
Staphylococcus aureus produces a _____ (yellow, red, or blue-green) pigment.
Yellow

2010-141
Pseudomonas aeruginosa produces a _____ (yellow, red, or blue-green) pigment.
Blue-green

2010-141
Serratia marcescens produces a _____ (yellow, red, or blue-green) pigment.
Red

2010-141
_____ produces yellow "sulfur" granules.
Actinomyces israelii (remember: Israel has yellow sand)

2010-141
Protein A in Staphylococcus aureus binds to the _____ region of immunoglobulin and disrupts two immune functions, _____and _____.
Fc; Opsonization and phagocytosis

2010-141
Immunoglobulin A protease is secreted by which bacteria?
Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria

2010-141
What protein from Group A Streptococcus prevents phagocytosis by the body's immune cells?
M protein

2010-141
Where are the genes for exotoxin located?
In the plasmid or the bacteriophage

2010-142
Gram-negative rods that cause meningococcemia and sepsis involve which kind of toxin?
Endotoxins

2010-142
Where are the genes for endotoxin located?
In the bacterial chromosome

2010-142
Which organism produces an exotoxin that is heat stable?
Staphylococcus aureus

2010-142
In what structures and in what type of bacteria are endotoxins found?
Endotoxins are found in the outer membrane of most gram-negative bacteria and in Listeria

2010-142
Bacteria that cause tetanus, botulism, and diphtheria involve which kind of toxin?
Exotoxins

2010-142
_____ (endotoxin, exotoxin) is heat stable; _____ (endotoxin, exotoxin) is not.
Endotoxins (stable at 100°C for 1 hour), exotoxins (destroyed rapidly at 60°C, except staphylococcal enterotoxin)

2010-142
Exotoxins _____ (are, are not) secreted; Endotoxins _____ (are, are not) secreted.
Exotoxins are secreted; endotoxins are not secreted

2010-142
Which bacterial toxin (endotoxin or exotoxin) can be used as a vaccine?
Exotoxin toxoid is used as a vaccine against exotoxin-producing organisms

2010-142
Exotoxins are found in which of the following: gram-negative bacteria, gram-positive bacteria, or both?
Both gram-negative and gram-positive bacteria

2010-142
What is the difference in the chemical composition of endotoxin vs exotoxin?
Exotoxins are polypeptides whereas endotoxins are lipopolysaccharides

2010-142
What are the major clinical effects of endotoxin and how are they induced?
Fever and shock due to induction of tumor necrosis factor and interleukin-1

2010-142
Name four organisms that have adenosine diphosphate ribosylating A-B toxin.
Corynebacterium diphtheriae, Vibrio cholerae, Escherichia coli, and Bordetella pertussis

2010-143
What is the mechanism of botulinum toxin-induced paralysis?
Inhibition of the release of acetylcholine

2010-143
Pertussis toxin causes the _____ (stimulation/inhibition) of Gαi, which results in an _____ (increase/decrease) in cAMP
Inhibition; increase

2010-143
What does Shiga toxin do in the host cell?
Shiga toxin cleaves host cell rRNA inactivating the 60S ribosomal subunit

2010-143
What are the functions of the two components of the A-B toxins found in certain bacteria, such as Corynebacterium diphtheriae?
B (binding) allows endocytosis and A (active) ADP-ribosylates host cell proteins

2010-143
Which two organisms' adenosine diphosphate ribosylating A-B toxins stimulate adenylate cyclase?
Vibrio cholerae and Escherichia coli

2010-143
_____ (adenylate, guanylate) cyclase is stimulated by the heat-labile toxin of Escherichia coli, whereas _____ (adenylate, guanylate) cyclase is stimulated by the heat-stabile toxin of Escherichia coli.
Adenylate, guanylate (remember: labile like the air, stable like the ground)

2010-143
Which organism causes whooping cough?
Bordetella pertussis

2010-143
What is the characteristic finding of Clostridium perfringens plated on blood agar?
Double zone of hemolysis

2010-143
The superantigen released by Streptococcus pyogenes causes what syndrome?
Toxic shock-like syndrome (caused by erythrogenic toxin)

2010-143
What foods are associated with botulism?
Canned food and honey

2010-143
What is the effect of increased adenylyl cyclase activity caused by cholera toxin?
Increased chloride pumping into gut and decreased sodium absorption, pulling excess water into the gut

2010-143
Name two organisms that produce Shiga toxin.
Shigella and Escherichia coli O157:H7

2010-143
Which toxin produced by Staphylococcus aureus causes food poisoning?
Enterotoxin

2010-143
Staphylococcus aureus exfoliatin can cause what illness?
Staphylococcus scalded skin syndrome

2010-143
Name two characteristic organisms with superantigen exotoxins.
Staphylococcus aureus and Streptococcus pyogenes

2010-143
What organism causes pharyngitis with pseudomembrane formation?
Corynebacterium diphtheriae

2010-143
How does Bordetella pertussis toxin cause lymphocytosis?
By the inhibition of the chemokine receptor

2010-143
What are the symptoms of toxic shock syndrome?
Fever, rash, and shock

2010-143
Clostridium tetani tetanus causes lockjaw by decreasing the level of what neurotransmitters?
Glycine and GABA (both are inhibitory neurotransmitters)

2010-143
Superantigens directly bind to which two receptors?
Major histocompatibility complex II and T-lymphocyte receptor

2010-143
Which antibody is used to help diagnose rheumatic fever?
Antistreptolysin O antibody

2010-143
Exaggerated release of cytokines caused by Shiga toxin can lead to what syndrome?
Hemolytic-uremic syndrome

2010-143
The toxin released by what bacterium produces what is commonly referred to as rice-water diarrhea?
Vibrio cholerae

2010-143
Which organism causes gas gangrene and what toxin is responsible?
Clostridium perfringens causes gas gangrene by release of its α-toxin (lecithinase)

2010-143
Which two Staphylococcus aureus toxins cause disease in humans?
Toxic shock syndrome toxin 1 and enterotoxin

2010-143
Diphtheria toxin causes pharyngitis and a pseudomembrane in the throat by the adenosine diphosphate ribosylation of what factor?
Elongation factor 2

2010-143
The binding of superantigens to MHC II and T-cell receptor results in the widespread release of what factors?
Interferon-γ and IL-2

2010-143
How does anthrax edema factor differ from pertussis, cholera, and Escherichia coli toxin induction of cAMP production?
Anthrax edema factor is itself an adenylate cyclase, whereas pertussis, cholera, and Escherichia coli toxins permanently activate endogenous adenylate cyclase

2010-143
Pertussis toxin causes whooping cough by permanently disabling which protein?
Gi (Turns the off off)

2010-143
Both cholera and pertussis toxins act by adenosine diphosphate ribosylation that permanently _____ (activates/inactivates) adenyl cyclase, thereby _____ (increasing/decreasing) cAMP.
Activates; increasing

2010-143
What is the mechanism of action of Bacillus anthracis edema factor?
Edema factor is a bacterial form of adenylate cyclase, which increases levels of cAMP

2010-143
Vibrio cholerae toxin causes watery diarrhea by permanently activating which protein?
Gs

2010-143
What is the chemical composition of endotoxin and where is it found?
It is a lipopolysaccharide found in the cell walls of gram-negative bacteria

2010-144
The release of nitric oxide by endotoxin-activated macrophages results in what condition?
Hypotension (shock)

2010-144
Endotoxins activate the coagulation cascade via what factor?
Hageman factor

2010-144
Which component of the alternative complement pathway causes hypotension and edema?
C3a

2010-144
What type of bacteria has endotoxins, gram-positive or gram-negative?
Gram-negative bacteria (remember: eNdotoxin is an integral part of the cell wall of gram-Negative bacteria)

2010-144
The release of which cytokines by endotoxin-activated macrophages results in fever?
Interleukin-1 and tumor necrosis factor

2010-144
The activation of the coagulation cascade by endotoxins results in what condition?
Disseminated intravascular coagulation

2010-144
Which cell type is activated by endotoxins?
Macrophages

2010-144
The activation of macrophages by endotoxin results in the release of which substances?
Interleukin-1, tumor necrosis factor, and nitric oxide

2010-144
What is the most active part of an endotoxin?
Lipid A

2010-144
How is complement activated by endotoxins?
Via the alternative pathway

2010-144
During which phase of the bacterial growth curve is there rapid cell division?
Log phase

2010-144
What are the four phases of the bacterial growth curve?
Lag phase, log phase, stationary phase, and death phase

2010-144
During which phase of the bacterial growth curve is there metabolic activity without division?
Lag phase

2010-144
What causes cell death during the death phase of the bacterial growth curve?
Prolonged nutrient depletion and a buildup of waste products

2010-144
What is the cause of slowed growth during the stationary phase of the bacterial growth curve?
Nutrient depletion

2010-144
During which phase of the bacterial growth curve does spore formation occur in some bacteria?
Stationary phase

2010-144
In which of the following can chromosomal DNA not be incorporated into transferred DNA: generalized transduction, specialized transduction, F+ × F- conjugation, Hfr × F- conjugation and transposition.
F+ × F- conjugation

2010-145
When an F+ plasmid is incorporated into the chromosomal DNA of a bacterial cell, that cell is then termed an _____ cell.
Hfr

2010-145
What type of bacterial genetic transfer involves the direct uptake of purified DNA by both prokaryotes and eukaryotes?
Transformation

2010-145
When DNA is transferred from one chromosome (or plasmid) to another within the same cell it is called _____.
Transposition

2010-145
What kind of DNA is transferred during transposition: chromosomal, plasmid, or both?
Both

2010-145
What kind of DNA is transferred during transformation: chromosomal, plasmid, or both?
Both

2010-145
What type of bacterial genetic transfer involves the phage-mediated transfer of DNA between prokaryotes?
Transduction

2010-145
Are chromosomal and plasmid genes transferred in F+ × F- conjugation or in Hfr × F- conjugation?
Hfr × F- conjugation; ONLY plasmid genes are transferred in F+ × F- conjugation

2010-145
What type of transduction is described here: a lytic phage infects a bacterium, cleaves the bacterial DNA, and repackages bacterial DNA in viral capsids to infect other bacteria.
Generalized transduction

2010-145
What type of transduction is described here: a lysogenic phage infects a bacterium, inserts DNA into the chromosomal DNA of the bacterium, and repackages flanking chromosomal DNA into its capsid upon excision to infect other bacteria.
Specialized transduction

2010-145
The process of direct DNA transfer from one bacterium to another is called what?
Conjugation

2010-145
Name 5 bacterial toxins coded for in a lysogenic phage.
ShigA-like toxin, Botulism toxin, Cholera toxin, Diptheria toxin, Erythrogenic toxin of Streptococcus pyogenes (remember: ABCDE)

2010-145
Staphylococcus and Streptococcus are differentiated by which enzyme?
Catalase; Staphylococcus is catalase positive, and Streptococcus is catalase negative

2010-146
Name one gram-positive anaerobic rod.
Clostridium

2010-146
Name two coagulase-negative Staphylococcus species.
Staphylococcus saprophyticus and Staphylococcus epidermidis

2010-146
If agar shows clear hemolysis, which Streptococcus species could be present?
Streptococcus pyogenes or Streptococcus agalactiae

2010-146
Partial (green) hemolysis on agar is called what?
α-Hemolysis

2010-146
Gram-positive organisms are commonly classified into which two shapes?
Cocci or rods (bacilli)

2010-146
In which three ways can α-hemolytic Streptococcus species be differentiated?
By the presence of capsule, optochin sensitivity, and bile solubility

2010-146
Name four gram-positive rods.
Clostridium, Listeria, Bacillus, and Corynebacterium

2010-146
Which α-hemolytic streptococcus species has no capsule and is optochin resistant and bile insoluble?
Viridans streptococci (eg, Streptococcus mutans)

2010-146
Clear hemolysis around colonies on agar is called what?
β-Hemolysis

2010-146
Absence of hemolysis on agar is called what?
γ-Hemolysis

2010-146
How are β-hemolytic streptococci differentiated from each other?
By their bacitracin sensitivity (Streptococcus pyogenes is sensitive, Streptococcus agalactiae is resistant)

2010-146
Which Staphylococcus species is novobiocin sensitive?
Staphylococcus epidermidis

2010-146
What differentiates Staphylococcus aureus from and other staph species?
Other staph species are coagulase negative

2010-146
Which gram-positive cocci are found in chains?
Streptococcus

2010-146
What type of organisms stain purple/blue with Gram staining?
Gram-positive organisms

2010-146
Which α-hemolytic streptococcus species is encapsulated, optochin sensitive, and bile soluble?
Streptococcus pneumoniae

2010-146
True or False: Enterococcus faecalis is a γ-hemolytic, gram-positive, catalase-negative cocci.
True

2010-146
Which gram-positive cocci are found in clusters?
Staphylococcus

2010-146
What pattern of hemolysis do Streptococcus pneumoniae and viridans streptococci (eg, Streptococcus mutans) demonstrate?
α-Hemolysis

2010-146
Name two streptococci that are γ-hemolytic.
Enterococcus and Peptostreptococcus (anaerobic)

2010-146
Which Staphylococcus species is novobiocin resistant?
Staphylococcus saprophyticus

2010-146
Which β-hemolytic streptococcal species is bacitracin resistant?
Group B Streptococcus (Streptococcus agalactiae)

2010-146
Which β-hemolytic streptococcal species is bacitracin sensitive?
Group A Streptococcus (Streptococcus pyogenes)

2010-146
Streptococcus pyogenes is a type of group _____ Streptococcus, whereas Streptococcus agalactiae is a type of group _____ Streptococcus.
A, B

2010-146
What type of hemolysis do both group A and group B streptococci have in common?
β-Hemolysis

2010-146
Group A streptococci are bacitracin _____ (resistant, sensitive); group B streptococci are bacitracin _____ (resistant, sensitive).
Sensitive; resistant (remember: Bacitracin: group B are Resistant, whereas group A are Sensitive (B-BRAS)

2010-146
Streptococcus viridans is optochin _____ (resistant, sensitive); streptococcus pneumoniae is optochin _____ (resistant, sensitive).
Resistant; sensitive (remember, Optochin: Viridans Resistant and Pneumonia Sensitive; OVRPS- overpass)

2010-146
Staphylococcus saprophyticus is novobiocin _____ (resistant, sensitive); staphylococcus epidermidis is novobiocin _____ (resistant, sensitive).
Resistant; sensitive (remember: On the staph retreat there was NO StRES; Novobiocin: Saprophyticus Resistant, Epidermidis Sensitive)

2010-146
Name the two types of α-hemolytic bacteria.
Streptococcus pneumoniae and Viridans streptococci

2010-146
Which organism is α-hemolytic, catalase negative, and optochin sensitive?
Streptococcus pneumoniae

2010-146
Which β-hemolytic organism is both catalase and coagulase positive?
Staphylococcus aureus

2010-146
Name four β-hemolytic bacteria.
Staphylococcus aureus, Streptococcus pyogenes, Streptococcus agalactiae, and Listeria monocytogenes

2010-146
Which β-hemolytic organism has tumbling motility, causes meningitis in newborns, and is found in unpasteurized milk?
Listeria monocytogenes

2010-146
Why do people with chronic granulomatous disease (nicotinamide adenine dinucleotide phosphate oxidase deficiency) get recurrent infections by catalase-producing organisms?
Bacterial catalase easily degrades the little hydrogen peroxide produced, compromising the ability of neutrophils to kill bacteria

2010-147
Which gram-positive cocci are catalase positive?
Staphylococci

2010-147
What bacterial enzyme degrades hydrogen peroxide?
Catalase

2010-147
What differentiates Staphylococcus aureus from Staphylococcus epidermidis and Staphylococcus saprophyticus?
Coagulase (Staphylococcus aureus is coagulase positive)

2010-147
What antimicrobial product produced by polymorphonuclear lymphocytes is a substrate for myeloperoxidase?
Hydrogen peroxide

2010-147
What is the function of Protein A, a Staphylococcus aureus virulence factor?
Binding to fragment crystallizable region-immunoglobulin G, to inhibit complement fixation and phagocytosis

2010-147
Staphylococcus aureus can cause rapid-onset food poisoning as a result of what product?
Preformed enterotoxins

2010-147
Methicillin-resistant Staphylococcus aureus is resistant to methicillin because of its altered structure of what protein?
Penicillin-binding protein

2010-147
Which organism produces toxic shock syndrome toxin 1?
Staphylococcus aureus

2010-147
Name five types of infections caused by Staphylococcus aureus.
Skin infections, organ abscesses, pneumonia, acute bacterial endocarditis, and osteomyelitis

2010-147
Staphylococcus aureus can cause which toxin-mediated conditions?
Toxic shock syndrome (toxic shock syndrome toxin 1), scalded skin syndrome (exfoliative toxin), and rapid-onset food poisoning (enterotoxins)

2010-147
What is the pathophysiology of toxic shock syndrome?
Toxic shock syndrome toxin 1 acts as a superantigen and causes widespread release of cytokines from T cells

2010-147
How does Staphylococcus epidermis infect prosthetic devices and intravenous catheters?
By producing adherent biofilms

2010-147
What bacterium found in normal skin flora commonly contaminates blood cultures and infects prosthetic devices and catheters?
Staphylococcus epidermis

2010-147
What four common infections does Staphylococcus pneumoniae cause?
Meningitis, Otitis media, Pneumonia, and Sinusitis (remember: MOPS are Most OPtochin Sensitive)

2010-147
Streptococcus pneumoniae sepsis occurs at a higher rate in what two patient populations?
Sickle cell anemia and asplenic patients

2010-147
Name two ways Streptococcus pneumoniae evades the immune system.
Immunoglobulin A protease, encapsulation

2010-147
What is distinct about the pneumonia caused by pneumococcus?
"Rust"-colored sputum

2010-147
Streptococcus _____(mutans/sanguis) causes subacute bacterial endocarditis; Streptococcus _____(mutans/sanguis) causes dental caries.
Sanguis; mutans
Sensitivity to which substance differentiates Streptococcus pneumoniae from Streptococcus viridans in laboratory testing?
Optochin; Streptococcus viridans is resistant (remember: Streptococcus viridans is in the mouth because it is not afraid of the chin (optochin))
Which group of organisms are part of the normal flora of the oropharynx and can cause dental caries and subacute bacterial endocarditis?
Viridians group streptococci
Human antibodies to Streptococcus M protein enhance host defenses but increase the risk for which complication of streptococcal infection?
Rheumatic heart disease

2010-148
Streptococcus pyogenes is associated with what three major classes of disease?
Infectious, immunogenic, and toxigenic

2010-148
What blood test would detect a recent Streptococcus pyogenes infection?
An antistreptolysin O titer

2010-148
Rheumatic fever is associated with what five symptoms?
Subcutaneous nodules, Polyarthritis, Erythema marginatum, Chorea, and Carditis (remember, there is no "RHEUM" for SPECCulation)

2010-148
What three pyogenic infections does Streptococcus pyogenes cause?
Pharyngitis, cellulitis, and impetigo

2010-148
What two toxigenic diseases does Streptococcus pyogenes cause?
Scarlet fever and toxic shock syndrome

2010-148
What two immunologic conditions does Streptococcus pyogenes cause?
Rheumatic fever and glomerulonephritis (remember: PHaryngitis gives you rheumatic "PHever" and glomerulonePHitis)

2010-148
In what population does group B Streptococcus (Streptococcus agalactiae) cause pneumonia, meningitis, and sepsis?
Babies (remember: B for Babies)

2010-148
Streptococcus agalactiae are bacitracin _____ (sensitive/resistant) and _____(α/β/γ) -hemolytic.
Resistant, β

2010-148
Lancefield grouping is based on differences in what components of the bacteria?
C carbohydrate on the bacterial cell wall

2010-148
Enterococci resistant to which antibiotic are an important source of nosocomial infection?
Vancomycin

2010-148
How can group D enterococci be differentiated from nonenterococcal group D streptococci by lab testing?
Enterococci can grow in 6.5% sodium chloride, other group D streptococci cannot

2010-148
True or False? Penicillin G is effective treatment against enterococci.
False; enterococci are resistant to penicillin G

2010-148
What two infections do enterococci cause?
Urinary tract infection and subacute bacterial endocarditis

2010-148
What two infections does Streptococcus bovis cause in colon cancer patients?
Bacteremia and subacute endocarditis

2010-148
How does diphtheria toxin inhibit protein synthesis?
By the adenosine diphosphate ribosylation of elongation factor 2

2010-148
The symptoms of diphtheria are caused by what kind of toxin?
Exotoxin (encoded on the β-prophage)

2010-148
How can diphtheria be prevented?
Toxoid vaccine; usually administered in combination with tetanus vaccine

2010-148
A young patient presents with pseudomembranous pharyngitis; what medium could be used to culture the most likely etiologic agent?
Corynebacterium diphtheriae grows on tellurite agar (coryne = club shaped)

2010-148
How is a laboratory diagnosis of diphtheria made based on microscopic appearance?
The presence of gram-positive rods with metachromatic granules (blue and red in color)

2010-148
What disease is caused by Corynebacterium diphtheriae?
Diphtheria; characterized by pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy

2010-148
What advantages do bacteria gain by taking the form of a spore?
They become highly resistant to destruction by heat and chemicals and require no metabolic activity in nutrient-poor settings

2010-148
What type of bacteria form spores?
Gram-positive rods

2010-148
What five soil-dwelling, gram-positive rods are spore formers?
Bacillus anthracis, Bacillus cereus, Clostridium perfringens, Clostridium botulinum, and Clostridium tetani

2010-148
Why is it important to autoclave surgical equipment?
To kill bacterial spores

2010-148
Which gram-positive bacilli are responsible for the flaccid paralysis caused by exposure to improperly canned foods?
Clostridium botulinum (remember: BOTulinum is from bad BOTtles of food)

2010-149
Which bacteria are gram-positive, spore-forming, obligate anaerobic bacilli?
Clostridia species

2010-149
Which exotoxin-producing, gram-positive bacillus is responsible for gas gangrene?
Clostridium perfringens (remember: PERFringens PERForates a gangrenous leg)

2010-149
What kind of toxin produced by Clostridium tetani causes symptoms of tetanus?
An exotoxin called tetanospasmin

2010-149
Which gram-positive bacillus is responsible for pseudomembranous colitis?
Clostridium difficile (remember: DIfficile causes DIarrhea)

2010-149
What is the treatment of choice for pseudomembranous colitis caused by Clostridium difficile?
Metronidazole

2010-149
How does the pathogenesis of botulism differ between adults and babies?
Adults consume preformed toxin whereas babies consume spores in honey (floppy baby syndrome)

2010-149
What are the characteristics of the toxin produced by Clostridium botulinum?
Preformed, heat-labile toxin

2010-149
What kind of toxin is produced by Clostridium difficile?
A cytotoxin, which is an exotoxin that kills enterocytes and causes pseudomembranous colitis

2010-149
Name four clostridia species that produce exotoxins.
Clostridium tetani, Clostridium botulism, Clostridium perfringens and Clostridium difficile

2010-149
What is the predominant symptom of botulism?
Flaccid paralysis

2010-149
Describe the pathogenesis of the symptoms caused by Clostridium tetani?
Clostridium tetani toxins block glycine (an inhibitory neurotransmitter) release from Renshaw cells in the spinal cord, leading to spastic paralysis, lockjaw (trismus), and risus sardonicus (remember: TETanus is TETanic paralysis)

2010-149
What is the effect of the toxin produced by Clostridium perfringens?
α-Toxin (lecithinase) causes myonecrosis, gas gangrene, and hemolysis

2010-149
How does the toxin produced by Clostridium botulinum cause flaccid paralysis?
It inhibits acetylcholine release

2010-149
Pseudomembranous colitis often follows a course of which antibiotics?
Clindamycin or ampicillin

2010-149
The skin changes of cutaneous anthrax are caused by which two toxins?
Lethal factor and edema factor cause a black eschar with surrounding edema at the site of inoculation

2010-149
What gram-positive, spore-forming rod that produces a toxin causes a respiratory illness that is associated with black skin lesions and exposure to animal hides and fur?
Bacillus anthracis

2010-149
What is Woolsorters' disease?
Pulmonary infection of Bacillus anthracis due to inhalation of spores from contaminated wool

2010-149
How is the capsule produced by Bacillus anthracis unique?
It is the only bacterium to have a polypeptide capsule (contains D-glutamate)

2010-149
Bacillus anthracis toxin causes what kind of skin lesion?
Black skin lesions (painless eschars, necrosis) surrounded by edematous ring

2010-149
What are the two modes of anthrax inoculation?
Cutaneous and pulmonary

2010-149
The inhalation of Bacillus anthracis spores leads to which symptoms?
Flu-like symptoms that rapidly progress to fever, mediastinitis, pulmonary hemorrhage, and shock

2010-149
What distinguishes Listeria monocytogenes from all other gram-positive bacteria?
It is the only gram-positive bacterium to have an endotoxin

2010-149
How does Listeria monocytogenes move from cell to cell?
Listeria is an intracellular organism that induces "actin rockets" to move into new cells

2010-149
How does the disease caused by Listeria monocytogenes differ among adults, neonates, and immunocompromised individuals?
In healthy individuals it causes a mild gastroenteritis but can cause meningitis in neonates and immunocompromised patients

2010-149
How is Listeria monocytogenes acquired?
By ingestion of unpasteurized milk, cheese, or deli meats or by vaginal transmission during birth

2010-149
Listeria monocytogenes has what identifying characteristic on microscopy?
Tumbling motility

2010-149
What diseases does Listeria monocytogenes cause in pregnant women?
Amnionitis, septicemia, and spontaneous abortions

2010-149
What is a characteristic finding in the draining sinuses caused by Actinomyces israelii infection?
Yellow "sulfur granules"

2010-149
Which is an anaerobe: Actinomyces israelii or Nocardia asteroides?
Actinomyces israelii

2010-149
True or False? Actinomyces are part of the normal oral flora.
True

2010-149
Which two bacteria are gram-positive rods that form long-branching filaments that resemble fungi?
Actinomyces israelii and Nocardia asteroides

2010-149
How are infections with Actinomyces israelii and Nocardia asteroides treated?
SNAP: Sulfa for Nocardia; for Actinomyces, use Penicillin

2010-149
Which is a weakly acid-fast aerobe in soil: Actinomyces israelii or Nocardia asteroides?
Nocardia asteroides

2010-149
Describe the lesions caused by Actinomyces israelii.
Oral/facial abscesses that may drain through sinus tracts

2010-149
What type of disease does Nocardia asteroides cause in immunocompromised individuals?
Pulmonary infection

2010-149
What is the result of most primary tuberculosis infections?
The lung lesions heal by fibrosis and the patient has lifelong immunity and hypersensitivity (purified protein derivative positive)

2010-150
What are three reasons an individual would have a positive PPD test?
Current tuberculosis infection, previous exposure, BCG vaccination

2010-150
In what populations does tuberculosis most frequently develop into progressive lung disease?
HIV positive or malnourished individuals.

2010-150
What are four reasons a patient with tuberculosis exposure may have a negative purified protein derivative test due to anergy?
Steroids, malnutrition, immunocompromised, sarcoidosis

2010-150
When would a patient who has been exposed to tuberculosis have a negative PPD test?
If the patient is anergic

2010-150
What type of lesion is seen on x-ray of the lung fields of a patient with secondary tuberculosis?
A cavitary lesion in the upper lobe

2010-150
What are four possible outcomes of primary tuberculosis?
Fibrous healing, progressive lung disease, severe bacteremia, and preallergic lymphatic or hematogenous dissemination

2010-150
A host with tuberculosis who develops severe bacteremia may go on to develop what kind of tuberculosis?
Miliary tuberculosis; characterized by many small granulomas in multiple organs

2010-150
What type of lesion is seen on x-ray of the lung fields of a patient with primary tuberculosis?
Ghon complex (Ghon focus with hilar node involvement, usually in the lower lobes)

2010-150
Name five common sites of extrapulmonary tuberculosis.
Central nervous system (parenchymal tuberculoma or meningitis), vertebral body (Pott's disease), lymphatic system (lymphadenitis), renal system, and gastrointestinal system

2010-150
In a nonimmune host (eg, a child), what kind of tuberculosis occurs after infection with Mycobacterium tuberculosis?
Primary tuberculosis

2010-150
In a partially immune, hypersensitized host, what kind of tuberculosis occurs after reinfection with Mycobacterium tuberculosis?
Secondary tuberculosis

2010-150
Extrapulmonary tuberculosis involving the vertebral body is called what?
Pott's disease

2010-150
What happens to individuals with primary tuberculosis who have subsequent preallergic lymphatic or hematogenous dissemination?
Individuals develop dormant tubercle bacilli in several organs, which can be reactivated later in life

2010-150
The reactivation of dormant tuberculosis infection in the lungs results in what condition?
Secondary tuberculosis with a fibrocaseous cavitary lesion, usually in the upper lobes

2010-150
Tuberculosis granulomas with lobar and perihilar lymph node involvement are called what?
Ghon complex

2010-150
Infection with Mycobacterium avium-intracellulare is symptomatic in which patient group?
Patients with AIDS

2010-150
Name four clinically important mycobacteria.
Mycobacterium tuberculosis, Mycobacterium kansasii, Mycobacterium avium-intracellulare, and Mycobacterium leprae

2010-150
All mycobacteria have what staining property?
They are all acid-fast

2010-150
What are the symptoms of tuberculosis?
Fever, night sweats, weight loss, and hemoptysis

2010-150
What symptoms are caused by Mycobacterium kansasii?
Pulmonary tuberculosis-like symptoms

2010-150
What two mycobacteria species are often resistant to multiple drugs?
Mycobacterium tuberculosis and Mycobacterium avium-intracellulare

2010-150
What is another name for leprosy?
Hansen's disease

2010-151
True or False? Mycobacterium leprae can be grown in vitro.
False

2010-151
What are the two forms of Hansen's disease?
Lepromatous and tuberculoid

2010-151
What is the treatment of choice for leprosy?
Long-term oral dapsone

2010-151
Which of the two forms of leprosy is self-limited?
Tuberculoid

2010-151
How can the skin lesions of lepromatous and tuberculoid leprosy be differentiated?
Lepromatous skin lesions present diffusely over the skin and are communicable (failed cell-mediated immunity) whereas tuberculoid skin lesions are limited to a few hypoesthetic nodules

2010-151
Because Mycobacterium leprae likes cool temperatures, it tends to infect what areas of the body?
The skin and the superficial nerves

2010-151
Which of the two forms of leprosy indicates failed cell-mediated immunity and has a worse prognosis?
Lepromatous = Lethal

2010-151
The organism that causes leprosy has what animal reservoir in the United States?
Armadillos

2010-151
Describe the leonine facies of leprosy caused by Mycobacterium leprae.
Loss of eyebrows, nasal collapse, and lumpy earlobe

2010-151
What toxicity is associated with long-term oral dapsone treatment?
Hemolysis and methemoglobinemia

2010-151
What are two alternative treatment options for leprosy?
Rifampin and the combination of clofazimine and dapsone

2010-151
Name two slow lactose-fermenting, gram-negative rods.
Citrobacter and Serratia

2010-151
Gram-negative organisms can be classified into what three shapes?
Cocci, coccoid rods, and rods

2010-151
Gram-negative rods are differentiated by the fermentation of what substance?
Lactose

2010-151
Among nonlactose fermenters, the presence of what substance can be used to differentiate Pseudomonas from Shigella, Salmonella, and Proteus?
Oxidase (Pseudomonas is oxidase positive, Shigella, Salmonella, and Proteus are oxidase negative)

2010-151
Name three fast lactose-fermenting, gram-negative rods.
Klebsiella, Escherichia coli, and Enterobacter

2010-151
How are the two gram-negative cocci differentiated from each other?
By maltose fermentation (Neisseria meningitidis is a maltose fermenter; Neisseria gonorrhoeae is not)

2010-151
Name two gram-negative cocci.
Neisseria meningitidis and Neisseria gonorrhoeae

2010-151
What is a common source of Pasteurella infections?
Animal bites

2010-151
Name four organisms that are gram-negative, coccoid rods.
Haemophilus influenzae, Bordetella pertussis, Pasteurella, and Brucella

2010-151
Name five bacteria that grow pink colonies on MacConkey's agar.
Citrobacter, Klebsiella, Escherichia coli, Enterobacter, and Serratia (remember: test with MacConKEE'S)

2010-151
What type of bacteria grows pink colonies on MacConkey's agar?
Lactose-fermenting enteric bacteria

2010-151
What part of gram-negative organisms inhibits the entry of penicillin G and vancomycin?
The outer membrane

2010-151
True or False? Gram-negative organisms are resistant to penicillin and all of its derivatives.
False; some gram-negative organisms are susceptible to penicillin derivatives such as ampicillin

2010-151
Why can a vaccine to Neisseria gonorrhea not be created?
Rapid antigenic variation

2010-152
What three clinical syndromes can Neisseria meningitides cause?
Septicemia, meningitis, and Waterhouse-Friderichsen syndrome

2010-152
How is Neisseria meningitidis transmitted?
Respiratory and oral secretions

2010-152
Neisseria meningitides _____ (does/does not) ferment lactose; Neisseria gonorrhea_____ (does/does not) ferment lactose.
Does; does not

2010-152
Neisseria meningitides _____ (does/does not) have a polysaccharide capsule; Neisseria gonorrhea _____ (does/does not) have a polysaccharide capsule.
Does; does not

2010-152
Neisseria meningitides _____ (does/does not) have a vaccine; Neisseria gonorrhea _____ (does/does not) have a vaccine.
Does; does not

2010-152
What five types of infection can Neisseria gonorrhea cause?
Gonorrhea, pelvic inflammatory disease, septic arthritis, Fitz-Hugh-Curtis syndrome, and neonatal conjunctivitis

2010-152
How is Neisseria gonorrhoeae transmitted?
Sexually transmitted

2010-152
What is the method of transmission of Haemophilus influenzae?
Aerosol

2010-152
What kind of culture is required to grow Haemophilus influenzae?
Chocolate agar with factors V (nicotinamide adenine dinucleotide) and X (hematin)

2010-152
The Haemophilus influenzae vaccine is given to which age group?
Patients between the ages of 2 and 18 months

2010-152
What prophylactic measure is taken for close contacts of a patient with meningitis caused by Haemophilus influenzae?
Rifampin is given

2010-152
Describe the vaccine used against Haemophilus influenzae.
It contains type B capsular polysaccharide, conjugated to diphtheria toxoid or other proteins

2010-152
True or False? Haemophilus influenzae causes the flu.
False; influenza virus causes the flu

2010-152
Name four diseases that can be caused by Haemophilus influenzae.
Epiglottitis, Meningitis, Otitis media. and Pneumonia (remember: HaEMOPhilus)

2010-152
What is the treatment of choice for meningitis caused by Haemophilus influenzae?
Ceftriaxone

2010-152
Why is the capsular type B polysaccharide conjugated to the diphtheria toxin or other protein in the Haemophilus influenzae vaccine?
To increase the immature immune system's ability to recognize the toxin and immunoglobulin class switching

2010-152
A four-year-old child presents to the emergency room in distress, febrile, drooling and lethargic. On intubation, his epiglottis is noted to be swollen and red. What vaccine would likely have prevented this disease?
Haemophilus influenzae type B vaccine; the patient has epiglottitis

2010-152
Which type of Haemophilus influenzae causes the most invasive disease?
Capsular type B

2010-152
What kind of virulence factor is produced by Haemophilus influenzae?
Immunoglobulin A protease

2010-152
How can Legionnaires' disease and Pontiac fever be differentiated?
Legionnaires' disease presents as a severe pneumonia and fever; Pontiac fever presents as a mild flu-like syndrome

2010-152
What kind of medium is used to grow Legionella pneumophila?
Charcoal yeast extract culture with iron and cysteine

2010-152
Name two clinical syndromes caused by Legionella pneumophila.
Legionnaires' disease and Pontiac fever

2010-152
Several smokers in their sixties staying in a hotel develop fever, cough, and dyspnea. What is important to test for in their urine?
Legionella antigen

2010-152
How is Legionnaires' disease transmitted?
Via aerosol transmission from an environmental water source; no person-to-person transmission occurs

2010-152
What kind of stain is used to detect Legionella pneumophila?
Silver stain

2010-152
What is the treatment of choice for Legionnaires' disease?
Erythromycin or other macrolide antibiotic

2010-152
Why is silver stain normally used to view Legionella pneumophila?
Because it gram stains poorly (considered gram negative)

2010-152
Pseudomonas aeruginosa is an _____ (aerobic/anaerobic) gram- _____ (positive/negative) _____ (rod/cocci).
Aerobic gram-negative rod

2010-152
Exotoxin A produced by Pseudomonas aeruginosa inactivates what human enzyme used in protein synthesis?
Elongation factor 2

2010-152
What is a common infection source for Pseudomonas aeruginosa?
Water; such as in swimmer's ear and hot tub folliculitis

2010-152
Which patient population is particularly susceptible to pneumonia caused by Pseudomonas aeruginosa?
Cystic fibrosis patients

2010-152
Persons with diabetes are particularly susceptible to which types of pseudomonal infections?
Osteomyelitis and malignant otitis externa; otitis externa is termed malignant when there is involvement of the bone

2010-152
What is the treatment of choice for Pseudomonas aeruginosa infection?
Aminoglycoside plus an extended-spectrum penicillin (eg, piperacillin, ticarcillin)

2010-152
Is Pseudomonas aeruginosa oxidase positive or oxidase negative?
Oxidase positive

2010-152
What distinctive color and odor does Pseudomonas aeruginosa exhibit?
Blue-green color (due to pyocyanin) with a grape-like odor

2010-152
A teenager with cystic fibrosis develops fever and dyspnea and is coughing up blue-green sputum. What do you expect to see on gram stain of the sputum?
Gram-negative rods (likely Pseudomonas)

2010-152
What nonlactose-fermenting gram-negative rod is commonly associated with wound and burn infections?
Pseudomonas aeruginosa

2010-152
What six clinical syndromes is Pseudomonas aeruginosa infection associated with?
Pneumonia, Sepsis, External otitis, Urinary tract infection, Drug use, Diabetic Osteomyelitis, and hot tub folliculitis (remember: PSEUDOmonas)

2010-152
True or False? Pseudomonas aeruginosa is a lactose fermenter.
False; it is a nonlactose fermenter

2010-152
What type of toxin causes fever and hypotension in pseudomonas sepsis?
Endotoxin

2010-152
Motile enterobacteriaceae species have what type of antigen?
Flagellar (H) antigen

2010-153
Escherichia coli, Salmonella, Shigella, Klebsiella, Enterobacter, Serratia, and Proteus belong to which bacterial family?
Enterobacteriaceae

2010-153
All enterobacteriaceae species ferment _____ and are oxidase _____.
Glucose; negative

2010-153
What does the capsular (K) antigen tell you about the enterobacteriaceae species?
Certain K antigens are correlated with more virulent species

2010-153
What is the somatic (O) antigen?
The polysaccharide of endotoxin

2010-153
All species in the enterobacteriaceae have what type of antigen?
Somatic (O) antigen, which is the endotoxin polysaccharide

2010-153
Which toxins mediate the diarrhea caused by enterotoxigenic Escherichia coli?
Labile toxin/stable toxin

2010-153
What three types of Escherichia coli do not invade the intestinal mucosa?
Enterohemorrhagic, enterotoxigenic, enteropathogenic; only enteroinvasive Escherichia coli invades the mucosa

2010-153
What differentiates the disease caused by enteroinvasive Escherichia coli and enterohemorrhagic Escherichia coli?
Both cause dysentery, but with enteroinvasive, both the toxin and the microbe cause necrosis and inflammation; with enterohemorrhagic, only the toxin does

2010-153
A seven-year-old child has a burger at a barbeque and subsequently develops diarrhea. He then ceases urinating, becomes lethargic, and is found to have low red blood cell and platelet counts. What is your diagnosis?
Hemolytic uremic syndrome secondary to infection with enterohemorrhagic Escherichia coli

2010-153
What disease is caused by enterotoxigenic Escherichia coli?
Traveler's diarrhea

2010-153
What is the pathophysiology of hemolytic uremic syndrome?
Endothelial swelling and narrowing leads to mechanical hemolysis (anemia) and reduced renal blood flow (acute renal failure), with damaged endothelium consuming platelets (thrombocytopenia)

2010-153
How does enteropathogenic Escherichia coli cause diarrhea?
It adheres to the apical surface, flattens villi, decreasing absorption (this is NOT toxin mediated)

2010-153
What population tends to get diarrhea following enteropathogenic Escherichia coli infection?
Children

2010-153
Which Escherichia coli species produces shiga-like toxin?
Enteroinvasive and enterohemorrhagic Escherichia coli

2010-153
Aside from diarrhea/dysentery, what diseases does Escherichia coli commonly cause?
Cystitis, pyelonephritis, pneumonia, neonatal meningitis, and septic shock

2010-153
What potentially fatal systemic complication can be caused by enterohemorrhagic Escherichia coli infection?
Hemolytic uremic syndrome

2010-153
What bacteria classically causes "red currant jelly" sputum in a patient with pneumonia?
Klebsiella

2010-153
Klebsiella is a cause of what other nosocomial infection in addition to pneumonia?
Urinary tract infection

2010-153
An alcoholic man is admitted to the hospital with fever, dyspnea and is coughing up gelatinous red sputum. Chest x-ray is consistent with an abscess. What infection do you suspect?
Klebsiella (remember the "4 A's": Abscess, Alcoholic, Aspiration, and diAbetics)

2010-153
How does Shigella propel itself within the cell?
By actin polymerization

2010-153
Which of the following is motile and can disseminate hematogenously: Salmonella or Shigella?
Salmonella

2010-153
Which is more virulent: Salmonella or Shigella?
Shigella (101 Shigella organisms vs 105 Salmonella organisms)

2010-153
A woman presents to the clinic with fever, diarrhea, headache, and rose spots on her abdomen. What is the likely diagnosis?
The woman has typhoid fever caused by Salmonella typhi

2010-153
What do Salmonella and Shigella have in common?
They are both nonlactose-fermenting bacteria that invade the intestinal mucosa causing bloody diarrhea

2010-153
Chronic carriers of Salmonella harbor the bacteria where in their bodies?
The gallbladder

2010-153
Which leukocyte response is seen in salmonellosis?
Monocyte response

2010-153
What are the modes of transmission of Shigella?
The "4 F's": Food, Fingers, Feces, and Flies

2010-153
What mode of propulsion do Salmonella use to disseminate?
Flagella

2010-153
Which antibiotics should be used to treat salmonellosis?
Salmonellosis should not be treated with antibiotics; doing so can prolong symptoms

2010-153
Which has an animal reservoir: Salmonella or Shigella?
Salmonella (except Salmonella typhi, which is only found in humans); Salmonella is often acquired from reptiles and poultry

2010-153
What are the usual modes of transmission of Yersinia enterocolitica?
Pet feces (eg, puppies) and contaminated milk or pork

2010-154
Yersinia enterocolitica infections can mimic what other diseases, particularly in teenagers?
Crohn's disease or appendicitis

2010-154
Yersinia enterocolitica outbreaks are common in what setting?
Day-care centers

2010-154
A patient with a chronic ulcer is found to have a positive urease breath test. How would you treat the patient?
Triple therapy: (1) Bismuth, metronidazole, and either tetracycline or amoxicillin; or (2) (more costly) metronidazole, omeprazole, and clarithromycin

2010-154
What enzyme in Helicobacter pylori helps to create an alkaline environment?
Urease

2010-154
Heliobacter pylori is a urease _____ (positive/negative), gram _____ (positive/negative) _____ (rod/cocci).
Urease-positive, gram-negative rod

2010-154
Heliobacter pylori causes what two pathologies in the gastrointestinal tract?
Duodenal ulcers and gastritis

2010-154
Heliobacter pylori is a risk factor for what two cancers?
Gastric adenocarcinoma and lymphoma

2010-154
Which spirochete species is visualized by dark-field microscopy?
Treponema, which causes syphilis

2010-154
What is the only spirochete that can be visualized by light microscopy with aniline dyes (ie, Wright's or Giemsa staining)?
Borrelia (remember: Big size)

2010-154
What are the three spirochete species that most commonly affect humans?
Borrelia (Big size), Leptospira, and Treponema (remember: BLT)

2010-154
Where is Leptospira interrogans commonly found in the environment?
In water contaminated with animal urine

2010-154
What is another name for Weil's disease?
Icterohemorrhagic leptospirosis

2010-154
Leptospirosis is most prevalent in which geographical locations?
The tropics

2010-154
What is the cause of azotemia and jaundice in patients with Weil's disease?
Renal and liver failure

2010-154
A farmer in the tropics with contaminated water sources presents with fever, headache, abdominal pain, photophobia, and conjunctivitis. What infection do you suspect?
Leptospira

2010-154
What is Weil's disease?
Severe leptospirosis, which presents with severe jaundice, azotemia, fever, hemorrhage, and anemia

2010-154
Which mammals are required for the life cycle of the Ixodes tick?
Deer and mice

2010-154
The tick Ixodes, which carries Borrelia burgdorferi, is also the vector for what other pathogen?
Babesia

2010-154
A child in Connecticut presents with Bell's palsy. What infectious disease must be considered as a diagnosis?
Lyme disease

2010-154
The classic symptom of Lyme disease, erythema chronicum migrans, has what appearance?
An expanding "bull's eye" red rash with central clearing

2010-154
What are the treatments of choice for Lyme disease?
Doxycycline and ceftriaxone

2010-154
What bacteria causes Lyme disease?
Borrelia burgdorferi

2010-154
In what region of the United States is Lyme disease common?
The northeastern United States

2010-154
What organs are affected in patients with Lyme disease?
The skin, the joints, the central nervous system, and the heart

2010-154
What are the three stages of Lyme disease and their associated symptoms?
Stage 1: erythema chronicum migrans and flu-like symptoms; stage 2: neurologic and cardiac manifestations; stage 3: autoimmune migratory polyarthritis

2010-154
The organism that causes Lyme disease is transmitted by what vector?
The Ixodes tick

2010-154
Treponema pertenue causes what condition?
Yaws

2010-154
What bacteria causes syphilis?
Treponema pallidum

2010-154
What are the symptoms commonly associated with yaws?
Joint deformities following keloid healing of skin, bone and joint infection

2010-154
Treponemes belong to what group of bacteria?
Spirochetes

2010-154
What tropical infection is not a sexually transmitted disease but results in a positive venereal disease research laboratory test?
Yaws

2010-154
Is second-degree syphilis a localized or disseminated disease?
Disseminated (remember: Secondary syphilis = Systemic)

2010-155
Third-degree syphilis can present with what neurologic defects?
Tabes dorsalis (resulting in broad-based gait, ataxia, and positive Romberg test) and Argyll Robertson pupil

2010-155
What is the treatment of choice for syphilis?
Penicillin G

2010-155
Second-degree syphilis presents with what type of skin manifestations?
A maculopapular rash on palms and soles and condylomata lata

2010-155
First-degree syphilis presents with what type of lesion?
A painless chancre at the site of infection (localized disease)

2010-155
What causes aortitis in tertiary syphilis?
Destruction of the vasa vasorum

2010-155
Which stage of syphilis is characterized by broad-based ataxia, a positive Romberg sign, Charcot joints, and stroke-like symptoms?
Third-degree syphilis

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What signs and symptoms are associated with congenital syphilis?
Saber shins, saddle-nose deformity, neurological (cranial nerve VIII) deafness, Hutchinson's teeth, and mulberry molars

2010-155
Third-degree syphilis presents with what signs and symptoms?
Gummas, aortitis, tabes dorsalis, and Argyll Robertson pupil

2010-155
Where can treponemes be found during primary and secondary syphilis?
In chancres during primary syphilis and in condylomata lata during secondary syphilis

2010-155
Argyll Robertson pupil is associated with what disease?
Tertiary syphilis

2010-155
Describe the findings in a patient with an Argyll Robertson pupil.
Pupil dilation with accommodation but not with direct light

2010-155
If a venereal disease research laboratory test is positive but the fluorescent treponemal antibody absorption test is negative, what is the interpretation?
False-positive result for syphilis infection

2010-155
Which diagnostic test is most specific for treponemes, turns positive earliest during the course of disease, and remains positive for the longest time?
Fluorescent treponemal antibody absorption test (remember: FTA-ABS = Find The Antibody-ABSolutely)

2010-155
A positive venereal disease research laboratory test and a positive fluorescent treponemal antibody absorption test indicate what?
Active infection with a treponeme that causes syphilis

2010-155
What do negative venereal disease research laboratory test and positive fluorescent treponemal antibody absorption test results indicate?
Successful treatment of syphilis

2010-155
Which conditions give biologic false-positive results for the venereal disease research laboratory test?
Viral infection, drugs, rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus, and leprosy. (remember: VDRL = Viruses, Drugs, Rheumatic fever and arthritis, Lupus and leprosy)

2010-155
A positive venereal disease research laboratory indicates that antibodies have formed against what molecule?
Beef cardiolipin

2010-155
Which organism causes the plague?
Yersinia pestis

2010-155
What is the mode of transmission of the bubonic plague?
Flea bites

2010-155
Name two animal reservoirs for ticks that transmit Francisella tularensis.
Rabbits and deer

2010-155
How is Pasteurella multocida transmitted?
Animal bite (cats, dogs)

2010-155
What is the most common mode of transmission for the bacteria Bartonella henselae?
Cat scratch

2010-155
A dairy farmer presents with one week of fever that waxes and wanes without treatment. What is the diagnosis?
Brucella spp, which are found in dairy products or transmitted via contact with cows, sheep, and goats

2010-155
Name six medically important zoonotic bacteria.
Bartonella henselae, Borrelia burgdorferi, Brucella spp, Francisella tularensis, Yersinia pestis, and Pasteurella multocida, Ella (remember: Big Bad Bugs From Your Pet named Ella)

2010-155
What is the disease caused by Bartonella?
Cat scratch fever

2010-155
What infection is caused by Pasteurella multocida?
Cellulitis after cat and dog bites

2010-155
What is the animal reservoir for ticks transmitting Yersinia pestis?
Rodents (especially prairie dogs)

2010-155
What dermatologic finding can Bartonella cause in immunocompromised individuals?
Bacillary angiomatosis (can be mistaken for Kaposi sarcoma)

2010-155
What organism causes tularemia?
Francisella tularensis

2010-155
How is Francisella tularensis transmitted?
Tick bites

2010-155
What organism transmitted by dairy products and contact with animals causes undulant fever?
Brucella spp (remember: Unpasteurized dairy products give you Undulant fever)

2010-155
A women presents with fishy gray vaginal discharge. What is the likely diagnosis and what will you prescribe?
Bacterial vaginosis caused by Gardnerella; treatment with metronidizole

2010-156
What are clue cells?
Vaginal epithelial cells covered with bacteria to the point where intracellular organelles are obscured

2010-156
What anaerobic bacteria other than Gardnerella vaginalis is frequently involved in vaginosis?
Mobiluncus

2010-156
Is Gardnerella vaginalis considered a sexually transmitted disease?
No, it is not a sexually transmitted disease, although it is more common in sexually active women

2010-156
What kind of cells (seen on a wet mount of vaginal discharge) are diagnostic of infection with Gardnerella vaginalis?
Clue cells (vaginal epithelial cells covered with bacteria)

2010-156
What is the treatment of choice for vaginosis caused by Gardnerella vaginalis?
Metronidazole

2010-156
What kind of discharge is produced in vaginosis caused by Gardnerella vaginalis?
Off-white/gray vaginal discharge, fishy odor

2010-156
Why is Coxiella considered an atypical rickettsia?
Because it causes pneumonia, instead of the classic triad of fever, headache, and rash, and it is the only one not carried by an arthropod vector

2010-156
True or False? Rickettsiae are facultative intracellular parasites.
False; Rickettsiae are obligate intracellular parasites

2010-156
What is the classic triad of symptoms caused by a rickettsial infection?
Fever, headache, and rash (vasculitis)

2010-156
Rickettsiae are obligate intracellular parasites because they require which two cofactors?
Coenzyme A and nicotinamide adenine dinucleotide

2010-156
Rickettsiae are obligate intracellular parasites that are transmitted by what type of vector?
Arthropods (except Coxiella, which is transmitted by aerosol)

2010-156
Epidemic typhus is caused by what bacterium?
Rickettsia prowazekii

2010-156
What disease does Rickettsia rickettsii cause?
Rocky Mountain spotted fever

2010-156
The pathogen that causes Rocky Mountain spotted fever is carried by what vector?
Ticks

2010-156
Endemic typhus is caused by what bacterium?
Rickettsia typhi

2010-156
How could one distinguish between the rash of Rocky Mountain spotted fever and that of typhus?
Rocky Mountain spotted fever starts in the periphery and moves inward whereas typhus starts in the trunk and moves outward (remember: Rickettsia on the wRists, Typhus on the Trunk)

2010-156
Does Q fever have a positive or negative Weil-Felix reaction assay?
Negative; a Weil-Felix assay is usually positive for typhus and Rocky Mountain spotted fever but negative for Q fever

2010-156
True or False? Coxiella burnetii can survive outside of the body for a long time.
True; Coxiella burnetii is the only rickettsial pathogen that can survive outside the body for long periods of time

2010-156
The pathogen that causes endemic typhus is carried by what vector?
Fleas

2010-156
Which rickettsial disease does not present with a rash?
Q fever is the only rickettsial infection that does not cause a rash

2010-156
The pathogen that causes epidemic typhus is carried by what vector?
Human body lice

2010-156
Ehrlichia is carried by what type of vector?
Tick

2010-156
What is the treatment of choice for all Rickettsial infections?
Tetracycline

2010-156
Q fever is caused by what bacterium?
Coxiella burnetii

2010-156
The pathogen that causes Q fever is carried by what vector?
Coxiella burnetii is an atypical Rickettsia in that it has no vector and is transmitted via aerosol

2010-156
A child who was recently camping in Virginia presents with a rash moving up the arms and legs, headache, fever, and a very ill appearance. What is your diagnosis and how will you treat?
Rocky Mountain spotted fever; treatment with tetracycline

2010-156
What three diseases start with a rash on the palms and soles?
Coxsackievirus A (hand-foot-and-mouth disease), Rocky Mountain spotted fever, and Syphilis (remember: you drive CARS with your palms and soles)

2010-156
Rocky Mountain spotted fever is endemic to what area?
The East Coast; despite its name it is not seen in the Rocky Mountains

2010-156
In a Weil-Felix reaction, antirickettsial antibodies in patient serum cross-react and agglutinate when mixed with antigens from what pathogen?
Proteus

2010-156
The Weil-Felix reaction is used to test for what pathogens?
Rickettsiae (this reaction is an assay for antibodies)

2010-156
Which rickettsial infection will have a negative Weil-Felix reaction?
Coxiella burnetii (which causes Q fever)

2010-156
What diseases are caused by Chlamydia trachomatis?
Reactive arthritis, conjunctivitis, nongonococcal urethritis, cervicitis, and pelvic inflammatory disease

2010-157
What are the treatments of choice for chlamydial infections?
Erythromycin or tetracycline

2010-157
The chlamydial cell wall is unique in that is lacks _____ _____.
Muramic acid

2010-157
What are the two forms of Chlamydiae?
The elementary body and the reticulate body

2010-157
Chlamydia psittaci has what animal reservoir?
Birds

2010-157
How can chlamydial infection be diagnosed by microscopy?
By cytoplasmic inclusions seen on Giemsa or fluorescent antibody staining

2010-157
Why are Chlamydia intracellular organisms?
Because they cannot make their own adenosine triphosphate

2010-157
Which two chlamydial species cause atypical pneumonia and how are they transmitted?
Chlamydia pneumoniae and Chlamydia psittaci; both are transmitted by aerosol

2010-157
During their life cycle, what form of chlamydia is infectious (ie, enters host cells)?
The Elementary body (small, dense) Enters the body via Endocytosis

2010-157
During their life cycle, what form of chlamydia replicates by fission?
The Reticulate (initial) body Replicates in the cell by fission

2010-157
Which Chlamydia trachomatis serotypes cause chronic infection and blindness in Africa?
Types A, B, and C (remember: Africa, Blindness, Chronic infection)

2010-157
What test is positive in lymphogranuloma venereum?
Frei test

2010-157
What other infection has similar symptoms to lymphogranuloma venereum?
Granuloma inguinale (donovanosis) caused by Calymmatobacterium granulomatis

2010-157
Which Chlamydia trachomatis serotypes cause urethritis, pelvic inflammatory disease, ectopic pregnancy, neonatal pneumonia, and neonatal conjunctivitis?
Types D through K

2010-157
What are the symptoms of lymphogranuloma venereum?
Acute lymphadenitis

2010-157
Which Chlamydia trachomatis serotypes cause lymphogranuloma venereum?
Types L1, L2, and L3 (remember: Lymphogranuloma)

2010-157
When is neonatal Chlamydia acquired?
As the infant passes through an infected birth canal

2010-157
What is the treatment of choice for neonatal disease caused by Chlamydia trachomatis?
Oral erythromycin

2010-157
What is a classic characteristic of chest x-ray findings in pneumonia caused by Mycoplasma?
The x-ray shows bilateral interstitial infiltrates, making the patient appear much sicker than he/she is

2010-157
Why is Mycoplasma pneumoniae resistant to all penicillins?
Because it has no cell wall

2010-157
What age group is most commonly affected by Mycoplasma pneumoniae infection?
Individuals younger than 30 years of age

2010-157
What is the best treatment for Mycoplasma pneumoniae infection?
Tetracycline or erythromycin

2010-157
Mycoplasma cell membranes are distinct because they contain _____.
Cholesterol

2010-157
A military recruit presents with a slow-onset, nonproductive cough with headache. Chest x-ray shows diffuse interstitial infiltrates, although the patient feels well. What is the likely diagnosis and how would you treat?
Mycoplasma pneumoniae; treatment with tetracycline or erythromycin

2010-157
What are the classic symptoms of the pneumonia that is caused by Mycoplasma pneumoniae?
Insidious onset, headache, nonproductive cough, and diffuse interstitial infiltrates seen on chest x-ray

2010-157
Mycoplasma pneumoniae infection is associated with a high titre of what antibodies?
Cold agglutinins (immunoglobulin M)

2010-157
Why are Mycoplasma pneumoniae not seen on gram stain?
No cell walls

2010-157
What bacteria is most commonly implicated in "walking pneumonia"?
Mycoplasma pneumoniae

2010-157
Mycoplasma pneumoniae can be grown on what medium?
Eaton's agar

2010-157
Name two systemic mycoses that are transmitted by inhalation of asexual spores.
Coccidioidomycosis and histoplasmosis

2010-158
Asexual fungal spores are also known as what?
Conidia

2010-158
Most fungal spores are _____ (sexual/asexual).
Asexual

2010-158
The yeast that causes paracoccidioidomycosis has what appearance on microscopy?
The "captain's wheel" appearance

2010-158
Describe the sizes of the four dimorphic fungi in relation to the size of a red blood cell.
Histoplasmosis: smaller; blastomycosis: same; coccidioidomycosis and paracoccidioidomycosis: larger

2010-158
What do histoplasmosis, paracoccidioidomycosis, and blastomycosis have in common?
They are all systemic mycoses caused by dimorphic fungi (mold in soil, but yeast in tissue (remember: mold = cold; heat = yeast)

2010-158
Histoplasmosis is most commonly transmitted via what substance?
Bird or bat droppings

2010-158
Blastomycosis is endemic in what areas of the United States?
The states east of the Mississippi River; it is also common in Central America

2010-158
All systemic mycoses can cause what type of illness?
Pneumonia that can disseminate

2010-158
A 40-year-old male from Central America presents with dyspnea and granulomatous skin nodules. What diagnosis do you expect?
Blastomycosis

2010-158
What microscopic appearance distinguishes coccidioidomycosis from all other dimorphic fungi?
Coccidioidomycosis is a spherule in tissue, not a yeast

2010-158
Systemic mycoses can mimic which other infectious disease with granuloma formation?
Tuberculosis

2010-158
In addition to pneumonia, what other illnesses can coccidioidomycosis cause?
Meningitis with dissemination to skin and bone

2010-158
Histoplasmosis is endemic in what area of the United States?
The Mississippi and Ohio River valleys

2010-158
Paracoccidioidomycosis is endemic in what area?
Latin America

2010-158
What are two colloquial names for disease caused by coccidioidomycosis?
San Joaquin Valley fever and desert valley fever (desert bumps)

2010-158
Histoplasmosis has what appearance under microscopy?
Macrophages filled with yeast (remember: Histo Hides in macrophages)

2010-158
Coccidioidomycosis is endemic in what area of the United States?
The southwestern United States, including California

2010-158
What is the treatment of choice for systemic infection with dimorphic fungi?
Amphotericin B

2010-158
What is the characteristic microscopic appearance of blastomycosis?
Big, broad-based budding

2010-158
What is the treatment of choice for local infection with dimorphic fungi?
Fluconazole or ketoconazole

2010-158
Tinea pedis, tinea cruris, tinea corporis, and tinea capitis are caused by what organisms?
Dermatophytes (ie, Microsporum, Trichophyton, Epidermophyton)

2010-159
What is the typical microscopic appearance of the agent causing tinea versicolor on KOH prep?
"Spaghetti and meatballs" (Malassezia furfur)

2010-159
Pets infected with Microsporum can be treated with what?
Topical azoles

2010-159
Tinea versicolor is caused by what organism?
Malassezia furfur

2010-159
An athlete presents with hypopigmented macules on her upper back after a summer of exercising. What is your diagnosis and what is the treatment?
Tinea versicolor; treat with topical miconazole and selenium sulfide

2010-159
What animals are commonly reservoirs for Microsporum?
House pets

2010-159
What causes hypopigmented patches of tinea versicolor?
Degradation of lipids by Malassezia furfur, producing acids that damage melanocytes

2010-159
What are the characteristic skin lesions of tinea pedis, cruris, corporis, and capitis?
Pruritic lesions with central clearing that resembles a ring (the infection is colloquially known as ringworm)

2010-159
Dermatophytes have what microscopic appearance in KOH prep?
Visible mold hyphae

2010-159
Which patient populations are especially susceptible to Aspergillus infections?
Those who are immunocompromised and those with chronic granulomatous disease

2010-159
Where are the abscesses in Mucor and Rhizopus infections found?
Nose and frontal lobe

2010-159
In what population is Candida albicanscommonly associated with endocarditis?
Intravenous drug users

2010-159
Where can the heavily encapsulated yeast of Cryptococcus neoformans be found in nature?
Soil and pigeon droppings

2010-159
What is the radiologic appearance of lesions found in the brain in patients with Cryptococcus neoformans?
Soap-bubble lesions

2010-159
How is Candida albicans diagnosed microscopically?
Yeast with pseudohyphae in culture, germ tubes at body temperature

2010-159
What four patient populations commonly contract oral and esophageal thrush as a result of Candida infection?
Neonates, steroid users, patients with diabetes, and patients with AIDS

2010-159
What immunodeficiency involves a specific inability to fight Candida albicans infections?
Chronic mucocutaneous candidiasis

2010-159
Cryptococcus neoformans causes what two diseases?
Cryptococcosis and cryptococcal meningitis

2010-159
Aspergillus fumigatus is a ____ (mold/yeast/dimorphic) with a _____ branching pattern and ____ hyphae.
Mold (not dimorphic); V-shaped (remember: Acute Angles in Aspergillus); septate

2010-159
How are Mucor and Rhizopus species morphologically different from Aspergillus species?
Mucor and Rhizopus have irregular, nonseptate hyphae with wide-angle branching, while Aspergillus have more uniform septate hyphae with acute-angle branching

2010-159
Aside from thrush and vulvovaginitis, what other superficial infections can Candida albicans cause?
Diaper rash

2010-159
On what medium is Cryptococcus neoformans cultured?
Sabouraud’s agar

2010-159
Are Mucor and Rhizopus species molds, yeasts, or dimorphic?
Molds

2010-159
Vulvovaginitis caused by Candida albicans commonly occurs in what types of patients?
Women with a high vaginal pH, diabetes, and/or a recent history of antibiotic use

2010-159
What stain can be used to visualize Cryptococcus neoformans?
India Ink

2010-159
What are the treatments for superficial and systemic Candida albicans infections?
Superficial infection: nystatin, systemic infection: amphotericin B

2010-159
Which two tests can be used to diagnose cryptococcal infection?
India ink stain and latex agglutination test

2010-159
Mucor and Rhizopus cause disease in which patient populations?
Diabetic patients with ketoacidosis and patients with leukemia

2010-159
How do Cryptococcus species appear on microscopy?
Yeasts with wide capsular halos that exhibit narrow-based budding

2010-159
What three diseases are caused by Aspergillus fumigatus?
Allergic bronchopulmonary aspergillosis, lung cavity aspergilloma ("fungus ball"), and invasive aspergillosis

2010-159
Is Cryptococcus neoformans a mold, a yeast, or dimorphic?
Yeast (not dimorphic)

2010-159
Pneumocystis jiroveci infection causes what type of disease?
A diffuse, interstitial pneumonia

2010-160
What is the mode of transmission of Pneumocystis jiroveci pneumonia?
Inhalation

2010-160
Infection with Pneumocystis jiroveci is asymptomatic except in what group of hosts?
Immunocompromised patients (eg, patients with AIDS)

2010-160
How is Pneumocystis jiroveci pneumonia diagnosed?
Sample obtained by lung biopsy or lavage; stained with methenamine silver

2010-160
What is the appearance of Pneumocystis jiroveci pneumonia on chest x-ray?
Diffuse, bilateral infiltrates

2010-160
Is Pneumocystis jiroveci a protozoan or a yeast?
A yeast (it was originally classified as a protozoan)

2010-160
What drugs are used to treat Pneumocystis jiroveci pneumonia?
Trimethoprim-sulfamethoxazole, pentamidine, and dapsone

2010-160
HIV-positive patients should be started on Pneumocystis jiroveci prophylaxis when their CD4+ cell count drops below what level?
Below 200 cells/mL; trimethoprim-sulfamethoxazole is used unless the patient is allergic

2010-160
What is the mode of transmission of sporotrichosis?
Traumatic introduction into the skin (eg, by a thorn; hence the name "rose gardener's disease")

2010-160
Under the microscope, what would one see in the pus from a lesion caused by Sporothrix schenckii
Cigar-shaped, budding yeast

2010-160
What is the treatment of choice for sporotrichosis?
Itraconazole or potassium iodide

2010-160
A women who gardens daily presents with a pustule on her forearm, with lesions tracing upward toward her axilla. What is the likely diagnosis?
Sporotrichosis (pustule with ascending lymphangitis)

2010-160
Is Sporothrix schenckii a mold, a yeast, or dimorphic?
Dimorphic

2010-160
What are the two laboratory diagnostic tests for amebiasis?
Serologic studies and stool examination for trophozoites or cysts

2010-161
What is the treatment of choice for Toxoplasma?
Sulfadiazine with pyrimethamine

2010-161
How many nuclei do Entamoeba cysts have?
Four

2010-161
What is the classic triad of congenital toxoplasmosis?
Chorioretinitis, hydrocephalus, and intracranial calcifications

2010-161
Toxoplasmosis causes brain lesions that have what appearance on imaging studies?
Ring-enhancing lesions

2010-161
In patients with AIDS, what does Cryptosporidium cause?
Severe diarrhea

2010-161
What laboratory test is used to diagnose Cryptosporidium?
Cysts on acid-fast stain of stool

2010-161
What laboratory test is used to diagnose giardiasis?
Trophozoites or cysts in stool

2010-161
What is the mode of transmission of Entamoeba histolytica?
Cysts in water

2010-161
What does Naegleria cause?
Rapidly fatal meningoencephalitis

2010-161
What is the treatment of choice for Cryptosporidium?
Only supportive care is possible; primary prevention by filtering water supply

2010-161
A 29-year-old hiker presents to the emergency room with 2 weeks of foul-smelling diarrhea and flatulence. He also reports a greasy, fat-like quality to his stool. What is your diagnosis and how will you treat?
Giardiasis (bloating, flatulence, and foul-smelling, fat-rich diarrhea) and metronidazole

2010-161
Many HIV-positive patients who drink tap water in your city present with severe diarrhea, and no treatment is offered. What organism is most likely responsible for this condition and how will you confirm the suspicion?
Cryptosporidium; look for cysts on acid-fast staining

2010-161
What is the treatment of choice for meningoencephalitis caused by Naegleria?
There is none

2010-161
What are two treatments for amebiasis?
Metronidazole and iodoquinol

2010-161
What disease is caused by Entamoeba histolytica?
Amebiasis (bloody diarrhea, liver abscess, and right upper quadrant pain)

2010-161
How is the diagnosis of Naegleria made?
Amoebas in the cerebrospinal fluid

2010-161
What is the mode of transmission of Naegleria?
Swimming in freshwater lakes (the organism enters via the cribriform plate)

2010-161
What is the mode of transmission of Giardia lamblia?
Cysts in water

2010-161
What two diagnostic tests are used for Toxoplasma infection?
Serology and biopsy

2010-161
What is the mode of transmission of Cryptosporidium?
Cysts in water

2010-161
Why should pregnant women avoid cats and cat feces?
Toxoplasma gondii cysts are found in cat feces and can cross the placenta, causing birth defects

2010-161
Toxoplasma causes disease in what two patient populations?
HIV-positive patients and neonates (congenital toxoplasmosis)

2010-161
What is the mode of transmission of Toxoplasma?
Cysts in meat or cat feces

2010-161
In immunocompetent patients, what does Cryptosporidium cause?
Mild, watery diarrhea

2010-161
Trypanosoma cruzi infections most frequently occur on what continent?
South America

2010-162
Distinguish the cyclic nature of fevers found in Plasmodium falciparum and Plasmodium vivax/ovale.
Plasmodium falciparum is more severe and cycles every day whereas Plasmodium vivax/ovale cycle every other day

2010-162
What are the symptoms of malaria?
Cyclic fever, headache, anemia, and splenomegaly

2010-162
What are the treatments of choice for babesiosis?
Quinine and clindamycin

2010-162
How is the diagnosis of African sleeping sickness made?
Blood smear

2010-162
What is the treatment of choice for Chagas' disease?
Nifurtimox

2010-162
What is the mode of transmission for African sleeping sickness?
Tsetse fly, with a painful bite

2010-162
The diagnosis of babesiosis can be made by seeing what pathognomonic sign on blood smear?
Lack of red blood cell pigment and Maltese cross

2010-162
What disease is caused by Trypanosoma cruzi?
Chagas' disease

2010-162
What treatment must be used to treat Plasmodium vivax and Plasmodium ovale when it is dormant in the liver?
Primaquine

2010-162
Babesiosis shares its mode of transmission with what other disease?
Lyme disease; both are transmitted by the Ixodes tick

2010-162
Describe the infection that is caused by Trichomonas vaginalis.
Vaginitis with foul-smelling greenish discharge that burns and itches

2010-162
What is the mode of transmission of Trichomonas vaginalis?
Sexual (it cannot exist outside of humans because it is unable to make cysts)

2010-162
What three organs are most commonly affected in Chagas' disease?
Heart, colon and esophagus (cardiomyopathy, megacolon, and megaesophagus)

2010-162
What is the treatment of choice for visceral leishmaniasis?
Sodium stibogluconate

2010-162
What is the mode of transmission of visceral leishmaniasis?
Sandfly

2010-162
How is the diagnosis of Trichomonas vaginalis made?
Mobile trophozoites on wet mount

2010-162
What is the treatment of choice for vaginitis caused by Trichomonas vaginalis?
Metronidazole; both the patient and sexual partners must be treated

2010-162
What drug regiment should be used to treat malaria?
Chloroquine; if resistant, mefloquine should be tried

2010-162
What disease is caused by Plasmodium species?
Malaria

2010-162
How is the diagnosis of visceral leishmaniasis made?
Macrophages containing amastigotes (the form that lack flagella)

2010-162
What is the treatment of choice for African sleeping sickness that affects the central nervous system?
Melarsoprol

2010-162
What disease is caused by Trypanosoma gambiense and Trypanosoma rhodesiense?
African sleeping sickness

2010-162
What causes recurring fevers in Trypanosoma infection?
Antigenic variation

2010-162
Parasitized red blood cells with Plasmodium falciparum infection tend to occlude capillaries in what three organs?
Kidney, lungs, and brain (cerebral malaria)

2010-162
What is the mode of transmission of Plasmodium species?
Anopheles mosquitoes

2010-162
How is the diagnosis of Trypanosoma cruzi made?
By visualizing the organism on blood smear

2010-162
What is the treatment of choice for blood-borne African sleeping sickness?
Suramin

2010-162
Which two species of Plasmodium form dormant hypnozites in the liver leading to relapsing malaria?
Plasmodium vivax and Plasmodium ovale

2010-162
Name four clinically important Plasmodium species.
Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum

2010-162
Describe the disease caused by Babesia (babesiosis).
Fever and hemolytic anemia

2010-162
A patient presents with a foul-smelling, itching, burning vaginitis with greenish discharge, and the responsible organism is diagnosed by trophozoites on wet mount. What organism is most likely responsible for this condition?
Trichomonas vaginalis

2010-162
A patient in an area in which Lyme disease is prevalent presents with malaria-like symptoms of fever and anemia. A blood smear shows red blood cells with a four-sided figure. What organism is most likely involved?
Babesia

2010-162
In what region of the world is Babesia infection most common?
The northeastern United States

2010-162
What disease is caused by Leishmania donovani?
Visceral leishmaniasis, also known as kala azar

2010-162
What is the mode of transmission of Trypanosoma cruzi?
Reduviid bug (the "kissing bug"), with a painless bite

2010-162
A patient presents with a spiking fever, hepatosplenomegaly and pancytopenia. He mentions recent travel in Africa. What is the most likely diagnosis?
Visceral leishmaniasis

2010-162
How is the diagnosis of malaria made?
Blood smear

2010-162
What are the three major types of helminths?
Nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes)

2010-163
How can infection with Toxocara canis lead to blindness?
Granuloma formation in the retina

2010-163
Taenia solium, Diphyllobothrium latum, and Echinococcus granulosus are examples of what type of organisms?
Cestodes (tapeworms)

2010-163
Infection with Trichinella spiralis causes what two symptoms?
Inflammation of the muscles (larvae encyst in muscle) and periorbital edema

2010-163
What roundworm can cause visceral larva migrans in addition to retinal granulomas?
Toxocara canis

2010-163
How is Toxocara canis transmitted?
Via food that is contaminated with eggs

2010-163
What is the treatment of choice for Toxocara canis?
Diethylcarbamazine

2010-163
What is the common name for Ancylostoma duodenale and Necator americanus?
Hookworms

2010-163
What is the treatment of choice for neurocysticercosis?
The -bendazoles

2010-163
Ancylostoma duodenale and Necator americanus can cause infection of what organ?
The intestines

2010-163
What is the treatment of choice for Wuchereria bancrofti?
Diethylcarbamazine

2010-163
What disease does Onchocerca volvulus cause?
River blindness

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What is the mode of transmission of the larval cysts of Taenia solium?
Consumption of undercooked pork

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What is the treatment of choice for Taenia solium intestinal infection?
Praziquantel

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What is the treatment of choice for Enterobius vermicularis?
Mebendazole or pyrantel pamoate

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What conditions are caused by Echinococcus granulosus?
Cysts in liver and anaphylaxis (if echinococcal antigens are released from cysts)

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What is the treatment of choice for Ascaris lumbricoides?
-bendazoles or pyrantel pamoate

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What is the mode of transmission of Diphyllobothrium latum?
Ingestion of larvae in uncooked freshwater fish

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What condition is caused by ingestion of Taenia solium larvae?
Intestinal tapeworms

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What is the treatment of choice for Ancylostoma duodenale and Necator americanus?
The -bendazoles or pyrantel pamoate

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What is the treatment of choice for Strongyloides stercoralis?
Ivermectin or -bendazoles

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Ascaris lumbricoides causes infection of what organ?
The intestines

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What are the symptoms of Dracunculus medinensis infection?
Inflammation and ulceration of the skin, often the feet and ankles

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What type of roundworm can be seen crawling in the conjunctiva of an infected individual?
Loa loa

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Why do surgeons inject ethanol into cysts of Echinococcus granulosus before removal?
Because release of echinococcal antigens can lead to anaphylaxis (ethanol neutralizes these antigens)

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What tapeworm can cause anemia secondary to vitamin B12 deficiency?
Diphyllobothrium latum

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How is Loa loa transmitted?
Via the deer, horse and mango flies

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The Scotch tape test is used to diagnose what type of infection?
Enterobius vermicularis (pinworms); tape is touched to the perianal area at night to look for presence of pinworm eggs

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What is the treatment of choice for Dracunculus medinensis?
Niridazole

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What are the symptoms of Strongyloides stercoralis infection?
Vomiting, diarrhea, and anemia

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Enterobius vermicularis causes infection of what organ?
The intestines

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What is the treatment of choice for Loa loa?
Diethylcarbamazine

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Why does infection with Ancylostoma duodenale and Necator americanus lead to anemia?
The worms suck blood through walls of the intestine causing iron deficiency

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Infection by Enterobius vermicularis is marked by what symptom?
Anal pruritis

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What is the treatment of choice for Echinococcus granulosus?
The -bendazoles

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What is the treatment of choice for Trichinella spiralis?
With -bendazole drugs

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What is the common name for Enterobius vermicularis?
Pinworm

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What is the treatment of choice for Onchocerca volvulus?
Ivermectin (remember: IVERmectin for rIVER blindness)

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What is the common name for Ascaris lumbricoides?
Giant roundworm

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What is the mode of transmission of Echinococcus granulosus?
The ingestion of eggs in dog feces

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How are Ancylostoma duodenale and Necator americanus transmitted?
Larvae penetrate the skin of the feet

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How is Wuchereria bancrofti transmitted?
Via the female mosquito

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What parts of the body does Loa loa infect?
The skin and the eyes

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What conditions are caused by ingestion of Taenia solium eggs?
Neurocysticercosis (mass lesions in the brain resembling Swiss cheese) and cysticercosis

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How is Enterobius vermicularis transmitted?
Via food that is contaminated with eggs

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Describe the pathogenesis of the disease caused by Wuchereria bancrofti?
Blockage of lymphatic vessels by the worm leads to elephantiasis after 9-12 months

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How is Onchocerca volvulus transmitted?
Female black flies

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Strongyloides stercoralis causes infection of what organ?
The intestines

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How is Trichinella spiralis transmitted?
Via undercooked meat (usually pork)

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How is Strongyloides stercoralis transmitted?
Via larvae in soil penetrating the skin

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What is the treatment of choice for Diphyllobothrium latum infection?
Praziquantel

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How is Dracunculus medinensis transmitted?
Through drinking water; Dracunculus is also known as Guinea Worm

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What two pathologies of the biliary tract are caused by Clonorchis?
Pigmented gallstones, secondary to biliary tract inflammation, and cholangiosarcoma

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How is Schistosoma transmitted to humans?
Through cercariae penetration of the skin in freshwater

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What is the treatment of choice for Schistosoma?
Praziquantel

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Name two helminths that are transmitted via undercooked pork.
Taenia solium and Trichinella spiralis

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Diethylcarbamazine is used to treat diseases caused by which helminths?
Loa loa, Toxocara canis, and Wuchereria bancrofti

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What fluke is transmitted via undercooked crab meat?
Paragonimus westermani

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Granulomas are formed in infections that are caused by which helminths?
Schistosoma and Toxocara canis

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Ivermectin is used to treat diseases caused by which helminths?
Strongyloides stercoralis and Onchocerca volvulus

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Praziquantel is used to treat diseases caused by which helminths?
Most of the cestodes and trematodes: Taenia solium, Diphyllobothrium latum, Schistosoma, Clonorchis sinensis, and Paragonimus westermani

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Snails are the host for what helminth?
Schistosoma

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Which helminths infect humans via the direct penetration of the skin?
Schistosoma, Ancylostoma duodenale (hookworm), and Strongyloides stercoralis

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What fluke is transmitted via undercooked fish?
Clonorchis sinensis

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What type of disease does infection with Paragonimus westermani cause?
Inflammation of the lungs with superimposed bacterial infection (leading to hemoptysis)

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What systemic effects does Schistosoma have once it enters the human?
It causes inflammation, fibrosis, and granulomas of the liver and spleen

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Which helminthic infections are treated with mebendazole or pyrantel pamoate?
Ancylostoma duodenale (hookworm), Ascaris lumbricoides (giant roundworm), and Enterobius vermicularis (pinworm)

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What is the treatment of choice for Paragonimus westermani?
Praziquantel

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Chronic infection with Schistosoma haematobium can lead to what cancer?
Squamous cell carcinoma of the bladder

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What is the treatment of choice for Clonorchis sinensis?
Praziquantel

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Which nematodes are transmitted cutaneously?
Strongyloides, Ancylostoma, and Necator (remember: these get into your feet from SANd)

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Which nematodes are transmitted by ingesting contaminated food?
Enterobius, Ascaris, and Trichinella (remember: you’ll get sick if you EAT these!)

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Name the helminth that cause microcytic anemia.
Ancylostoma and Necator

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Name the helminth that causes hematuria and bladder cancer.
Schistosoma haematobium

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Name the helminth that causes biliary tract disease and is associated with cholangiosarcoma.
Clonorchis sinensis

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Name the helminth that causes vitamin B12 deficiency.
Diphyllobothrium latum

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Name the helminth that causes portal hypertension.
Schistosoma mansoni

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Name the parasite that causes brain cysts and seizures.
Taenia solium

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Name the helminth that causes hemoptysis.
Paragonimus westermani

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Name the helminth that causes liver cysts.
Echinococcus granulosus

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Name the helminth that causes perianal pruritus.
Enterobius

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What do Trichomonas vaginalis and Chlamydia trachomatis have in common?
They both cause sexually transmitted diseases

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Treponema species cause what conditions?
Syphilis (Treponema pallidum) or yaws (Treponema pertenue)

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Typhoid fever is caused by what bacteria?
Salmonella typhi

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Trypanosoma species cause what conditions?
Chagas' disease and African sleeping sickness

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The three types of typhus are caused by what three bacteria?
Epidemic typhus = Rickettsia prowazekii; Endemic typhus = Rickettsia typhi; scrub typhus = Rickettsia tsutsugamushi

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What are the clinical presentations resulting from ingestion of Taenia solium eggs vs larvae?
The ingestion of tapeworm larvae causes intestinal infection whereas the ingestion of eggs causes neurocysticercosis

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Toxoplasma is what type of organism?
Protozoan (one of the TORCH infections)

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What are the different modes of transmission of Trichinella spiralis and Trichomonas vaginalis?
Trichinella spiralis is caused by eating undercooked meat; Trichomonas vaginalis is a sexually transmitted disease

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Trichomonas vaginalis and Chlamydia trachomatis both cause sexually transmitted diseases. How are they different?
Trichomonas vaginalis is a protozoan, whereas Chlamydia trachomatis is a bacterium

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Treponema is a type of _____, whereas Trypanosoma is a type of _____.
Spirochete (bacteria); protozoan

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What are the four components of an enveloped icosahedral virus structure?
Surface protein, lipid bilayer, capsid, and nucleic acid

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Structurally, what are the three main classes of viruses?
Naked icosahedral, enveloped icosahedreal, enveloped helical

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What are the two components of the naked icosahedral virus structure?
Nucleocapsid and nucleic acid

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What are the four components of the enveloped helical virus structure?
Surface protein; matrix or core protein; lipid bilayer; and nucleic acid and nucleocapsid protein

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In viral genetics, what is recombination?
It is the exchange of genes between two chromosomes by crossing over within regions of significant base sequence homology

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Viral genome reassortment occurs in viruses with what type of genomic structure?
Segmented genomes

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In viral genetics, when does complementation occur?
Complementation occurs when one of two viruses that infect the cell has a mutation that results in a nonfunctional protein and the nonmutated virus makes a functional protein that serves both viruses (the nonmutated virus "complements" the mutated one)

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Which type of viral genetic event can cause worldwide pandemics?
Reassortment, which happens when viruses with segmented genomes (eg, influenza virus) exchange segments

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What is a pseudovirion?
The genetic material of one virus coated by the surface proteins of a different virus

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In viral genetics, when does phenotype mixing occur?
Phenotype mixing occurs when the genome of virus A is coated with the surface proteins of virus B and infectivity is determined by the virus B protein coat, but the progeny is encoded by virus A generic material and will have the virus A coat

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In viral genetics, what is reassortment?
It is the exchange of segments among viruses with segmented genomes (eg, influenza virus)

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What is the difference between the immunity induced by a live, attenuated virus and that of killed virus vaccines?
Live, attenuated vaccines induce humoral and cell-mediated immunity whereas killed vaccines induce only humoral immunity

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Name two recombinant vaccines.
Hepatitis B virus and human papilloma virus vaccines

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Which human papillomavirus types does the human papillomavirus vaccine protect against?
Types 6, 11, 16, and 18; the types most likely to cause cervical cancer and genital warts

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What is the advantage of killed vaccines over live, attenuated vaccines?
Killed vaccines are more stable, whereas live, attenuated vaccines have reverted to virulence on very rare occasions

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What is the only live, attenuated vaccine that can be given to HIV-positive individuals?
MMR (measles, mumps, rubella)

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Live vaccines are dangerous to give to which populations?
Immunocompromised patients or their contacts

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Name five live, attenuated vaccines.
MMR (measles, mumps, rubella), Sabin polio, varicella zoster virus, yellow fever, smallpox (remember: "Live! One night only! See small yellow chickens get vaccinated with Sabin's and MMR")

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Name four killed virus vaccines.
Rabies, Influenza, Salk Polio, and hepatitis A virus (remember: RIP Always, and SalK = Killed)

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What is the antigen that is present in the hepatitis B virus vaccine?
Recombinant hepatitis B surface antigen

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Which three DNA viruses contain nonlinear DNA?
Papilloma, polyoma, and hepadna viruses, which contain circular DNA

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All DNA viruses contain double-stranded DNA, except for which family?
Parvoviridae, which has single-stranded DNA (remember: part-of-a-virus)

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All RNA viruses contain single-stranded RNA, except for which family?
Reoviridae (remember: all are single-strand RNA except "repeatovirus" [reovirus] is double-stranded RNA])

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Purified nucleic acids from which viruses are considered infectious?
Most double-stranded DNA viruses and positive-strand single-stranded RNA viruses

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The purified nucleic acids of what two double-stranded DNA viruses are not considered infectious?
Poxviruses and hepatitis B virus; both require enzymes not found in human cells for replication

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Why are negative-strand single-stranded RNA and double-stranded RNA viruses not infectious?
They require enzymes found in the complete virion to become infectious

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Are most viruses haploid or diploid?
Most are haploid (one copy of genetic material)

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What is the only virus that is not haploid?
Retroviruses (2 copies of single-stranded RNA)

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Do most RNA viruses replicate in the cytoplasm or the nucleus of the host cell?
Cytoplasm

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Which two RNA viruses replicate in the host cell nucleus?
The influenza virus and retroviruses

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With one exception, all DNA viruses replicate in what part of the host cell?
Nucleus

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All DNA viruses replicate in the nucleus of the host cell, except for which virus?
Poxvirus

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What are the seven naked (nonenveloped) viruses?
Calicivirus, Picornavirus, Reovirus, Parvovirus, Adenovirus, Papillomavirus, and Polyomavirus (remember: naked CPR and PAPP smear)

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From what structure are most viral envelopes derived?
Plasma membrane

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The herpesviruses acquire their envelopes from which component of the host cell?
Nuclear membrane

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Measles virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Adenovirus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
DNA; nucleocapsid

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Herpesviruses are _____ (DNA/RNA) _____ (enveloped/nucleocapsid) viruses.
DNA; enveloped

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Smallpox is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
DNA; enveloped

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Influenza virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Enteroviruses are _____ (DNA/RNA) _____ (enveloped/nucleocapsid) viruses.
RNA; nucleocapsid

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Rhinovirus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; nucleocapsid

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Rubella virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Rabies is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Name the three types of RNA nucleocapsid viruses.
Enteroviruses, rhinovirus, and reovirus (rotavirus)

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Reovirus (rotavirus) is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; nucleocapsid

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Papillomavirus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
DNA; nucleocapsid

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Parvovirus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
DNA; nucleocapsid

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Parainfluenza is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Name three DNA nucleocapsid viruses.
Adenovirus, papillomaviruses, parvovirus

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Respiratory syncytial virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Mumps virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Human T-lymphotropic virus is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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HIV is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
RNA; enveloped

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Hepatitis B is a _____ (DNA/RNA) _____ (enveloped/nucleocapsid) virus.
DNA; enveloped

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Name three enveloped DNA viruses.
Herpesviruses, hepatitis B virus, smallpox virus

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Name the seven DNA viruses.
Hepadnavirus, Herpesvirus, Adenovirus, Poxvirus, Parvovirus, Papillomavirus, and Polyomavirus (remember the mnemonic: HHAPPPPy viruses)

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All DNA viruses are linear except what three DNA viruses?
Hepadnavirus (circular, incomplete) and papillomavirus/polyomavirus (circular, supercoiled)

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In general, DNA viruses are _____ (single/double) stranded, _____ (linear/circular), icosahedral, and replicate in the _____ (nucleus/cytoplasm).
Double stranded; linear; nucleus

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All DNA viruses are icosahedral except which one?
Poxvirus; it is complex

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Which DNA virus does not replicate in the nucleus?
Poxvirus; it has a DNA-dependent RNA polymerase and can replicate without nuclear enzymes

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Which herpesvirus most often causes genital lesions in humans?
Herpes simplex virus type 2

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What is the largest DNA virus?
Poxvirus

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Chickenpox, zoster, and shingles are caused by what DNA virus?
Varicella zoster virus

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Which types of patients are particularly vulnerable to significant cytomegalovirus infection?
Immunosuppressed patients (especially transplant recipients) and the fetuses of infected mothers

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To what viral family does hepatitis B virus belong?
Hepadnavirus

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Which viral family is responsible for smallpox, cowpox, and molluscum contagiosum?
Poxvirus

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Vaccinia virus causes what condition?
Cowpox ("milkmaid's blisters")

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Adenovirus is most commonly responsible for what three conditions?
Febrile pharyngitis (sore throat), pneumonia, and conjunctivitis

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JC virus is the causative agent of what condition in HIV-positive patients?
Progressive multifocal leukoencephalopathy

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Which enzyme does hepatitis B virus have in common with retrovirus?
Reverse transcriptase

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What skin exanthem does parvovirus B19 cause in children?
Erythema infectiosum ("slapped-cheek" rash)

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Which disease caused by a poxvirus has been eradicated but could possibly be used in germ warfare?
Smallpox

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What type of disease does papillomavirus cause?
Genital warts, cervical intraepithelial neoplasia, and cervical cancer

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What is the smallest DNA virus?
Parvovirus

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Which herpesvirus most often causes oral lesions as well as keratoconjunctivitis?
Herpes simplex virus type 1

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Parvovirus B19 causes what condition in patients with sickle cell disease?
Aplastic crisis

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Name seven medically important herpesviruses.
Herpes simplex virus type 1, herpes simplex virus type 2, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, human herpesvirus type 6, and human herpesvirus type 8 (human herpesvirus 7 is not clinically significant)

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Which childhood illness is caused by human herpesvirus type 6?
Roseola (exanthem subitum)

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What two DNA virus families were originally categorized together as papovavirus?
Papillomavirus and polyomavirus

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Which DNA virus is associated with Kaposi sarcoma?
Human herpesvirus type 8 (Kaposi’s sarcoma-associated herpesvirus)

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Which is the only hepatitis-causing virus that is a DNA virus?
Hepatitis B virus

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What severe complication is seen in the fetuses of pregnant women who are exposed to parvovirus B19?
Hydrops fetalis (due to red blood cell destruction)

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Herpes genitalis and neonatal herpes are most commonly caused by what herpes virus?
Herpes simplex virus type 2

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How is varicella zoster virus transmitted?
Respiratory secretions

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What is the primary route of transmission of herpes simplex virus type 1?
Respiratory secretions and saliva

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Shingles, encephalitis and pneumonia can be caused by which herpesvirus?
Varicella zoster virus

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Human herpesvirus type 8 is primarily transmitted via what route?
Sexual contact

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Which herpesvirus causes gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, and herpes labialis?
Herpes simplex virus type 1

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Human herpesvirus type 8 can cause what disease in HIV-positive patients?
Kaposi sarcoma

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What histologic finding is characteristic of cells infected with cytomegalovirus?
"Owl's eye" intranuclear inclusions

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Epstein-Barr virus causes what conditions?
Infectious mononucleosis, Burkitt's lymphoma and nasopharyngeal carcinoma

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What is the most likely etiology for a mononucleosis-like presentation that is monospot test negative?
Cytomegalovirus

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Herpes encephalitis usually affects which lobe of the brain?
The temporal lobe

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Describe the clinical presentation of human herpesvirus type 6 infection.
Roseola: high fevers followed by a diffuse macular rash; human herpesvirus type 6 is one of the most common causes of febrile seizures in children

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Cytomegalovirus causes what conditions?
Congenital infection, mononucleosis, and pneumonia

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Where does varicella zoster virus remain dormant in the body after primary infection?
In the dorsal root and trigeminal ganglia

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How is herpes simplex virus type 2 primarily transmitted?
Via sexual contact and perinatally

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What are the modes of cytomegalovirus transmission?
Congenital, transfusion, sexual contact, saliva, urine, and organ transplantation

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How is Epstein-Barr virus transmitted?
Respiratory secretions and saliva

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Name six medically important herpesviruses.
Cytomegalovirus, Herpes simplex virus types 1 and 2, Human herpesvirus type 8, Epstein-Barr virus, Varicella zoster virus (remember: get herpes in a CHEVrolet)

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What is the Tzanck test?
A test to detect multinucleated giant cells in opened skin vesicles of herpes simplex virus type 1 and 2 and varicella zoster virus

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HSV-infected cells contain inclusion bodies known as what?
Cowdry A intranuclear inclusions

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Which herpesvirus is the most common cause of mononucleosis?
Epstein-Barr virus

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Epstein-Barr virus causes mononucleosis by infecting which cells?
B cells

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Epstein-Barr virus is associated with the development of which three types of malignancy?
Hodgkin's and endemic Burkitt's lymphoma and nasopharyngeal carcinoma

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What laboratory test can be used to diagnose mononucleosis?
Monospot test: heterophil antibodies detected by agglutination of sheep red blood cells

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A college student presents to the emergency department with fever, hepatosplenomegaly, pharyngitis and lymphadenopathy (especially posterior cervical nodes). Which viral infection should be suspected?
Epstein-Barr virus can cause mononucleosis, also known as the "kissing disease" because its peak incidence is 15-20 years old (peak "kissing years"); transmission is through saliva

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A complete blood count of a patient with infectious mononucleosis would show what abnormalities?
Atypical lymphocytes (circulating cytotoxic T cells)

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Name the four families of RNA viruses that have no envelope.
Reoviruses, picornaviruses, hepevirus and caliciviruses

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Which diseases are caused by arboviruses?
Yellow fever, dengue, St. Louis encephalitis, West Nile virus, Eastern equine encephalitis and Western equine encephalitis, California encephalitis, Crimean-Congo hemorrhagic fever

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True or False? All helical viruses are enveloped.
True

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What is the only positive-sense RNA virus with a helical capsid?
Coronavirus

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What are the three viral families with circular RNA?
Arenaviruses, bunyaviruses, and deltavirus

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Which clinically significant virus has a segmented linear RNA?
Influenza (an orthomyxovirus)

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All negative-sense RNA viruses have what type of capsid?
Helical

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Name the viral family that is made up of double-stranded RNA viruses with a double icosahedral capsid.
Reovirus

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Name six viral families that are single-strand, positive-sense, linear RNA viruses with icosahedral capsids.
Picornavirus, hepevirus, calicivirus, flavivirus, togavirus, and retrovirus

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The viruses that cause viral hepatitis A-E in humans belong to which families?
Picornavirus (hepatitis A), hepadnavirus (hepatitis B), flavivirus (hepatitis C), deltavirus (hepatitis D), hepevirus (hepatitis E)

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Hepatitis D virus belongs to which viral family?
Deltavirus

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Bunyaviruses are the causative agents of what four diseases?
California encephalitis, Sandfly/Rift Valley fevers, Crimean-Congo hemorrhagic fever and hantavirus

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Arenaviruses are the causative agents of what two diseases?
Lymphocytic choriomeningitis and Lassa fever encephalitis

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Filoviruses are the causative agents of what two diseases?
Ebola hemorrhagic fever and Marburg hemorrhagic fever; both are frequently fatal

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Rabies virus is what type of virus?
Rhabdovirus

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What disease does respiratory syncytial virus cause in babies?
Bronchiolitis

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What disease does parainfluenza virus cause?
Croup

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Name four medically important paramyxoviruses.
Parainfluenza, Respiratory syncytial virus, Measles (rubeola), and Mumps; remember: PaRaMyxoviruses

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Which medically important RNA virus belongs to the orthomyxovirus family?
Influenza

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Coronaviruses are the causative agents of what two diseases?
The common cold and severe acute respiratory syndrome (SARS)

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Human T-lymphotropic virus causes what disease?
T-lymphocyte leukemia

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Name two RNA viruses that have reverse transcriptase.
HIV (a retrovirus), and human T-lymphotropic virus

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Togaviruses cause what three diseases?
Rubella (German measles), Eastern equine encephalitis, and Western equine encephalitis

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Flaviviruses are responsible for what five diseases?
Hepatitis C virus, yellow fever, dengue, St. Louis encephalitis, and West Nile virus

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The structure of the genome of reovirus is unique among RNA viruses in what respect?
It has double-stranded RNA with 10-12 strands, whereas all other RNA viruses are single stranded

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Reovirus causes what condition?
Colorado tick fever

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Rotavirus belongs to which viral family?
Reoviruses

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Norwalk virus causes what condition?
Viral gastroenteritis

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Name a medically important calicivirus.
Norwalk virus

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Aseptic meningitis; myocarditis; herpangina; and hand, foot, and mouth disease are caused by which picornavirus?
Coxsackieviruses

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Which two RNA viruses cause the common cold?
Rhinovirus and coronavirus

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Which two picornaviruses commonly cause aseptic meningitis?
Echovirus and coxsackievirus

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What vaccines exist against poliovirus?
Salk (inactivated polio vaccine) and Sabin (oral polio vaccine)

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Name the six negative-stranded virus families.
Arenaviruses, Bunyaviruses, Paramyxoviruses, Orthomyxoviruses, Filoviruses, and Rhabdoviruses (remember: Always Bring Polymerase Or Fail Replication)

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What must a negative-stranded DNA virus do to replicate within a human cell?
Transcribe its negative strand to a positive strand; it does this by carrying an RNA-dependent RNA polymerase

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How many segments of RNA make up the influenza virus genome?
Eight

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Name four segmented RNA viruses.
Bunyaviruses, Orthomyxoviruses (influenza), Arenaviruses, and Reoviruses (remember: BOAR)

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All segmented viruses are ____ (RNA/DNA) viruses.
RNA

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The reassortment of influenza virus RNA segments results in antigenic _____ (shift/drift) and is a cause of _____ (pandemics/epidemics).
Shift; pandemics

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Picornaviruses (except rhinovirus and hepatitis A virus) can cause what condition in humans?
Aseptic meningitis

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Picornaviruses are (small/large) _____, (RNA/DNA) _____ viruses.
Small, RNA (remember: PicoRNAvirus = RNA virus)

2010-170
What five RNA viruses are picornaviruses?
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, and Hepatitis A virus (remember: PERCH on a "peak" = Pico)

2010-170
Why are humans susceptible to multiple recurrent infections with rhinovirus causing cold-like symptoms?
Because there are more than 100 serologic types of rhinovirus

2010-170
What type of virus is rhinovirus?
A nonenveloped RNA virus that belongs to the picornavirus family

2010-170
Yellow fever is caused by a virus that belongs to what viral family?
Flavivirus, which is an arbovirus (flavi = yellow)

2010-170
How is yellow fever transmitted?
By Aedes mosquitoes

2010-170
What histologic finding on liver biopsy is seen in patients with yellow fever?
Councilman bodies (acidophilic inclusion bodies)

2010-170
A 30-year-old man presents to the emergency room with a high fever, black vomitus, and a yellow discoloration to his skin. What is the most likely etiology?
Yellow fever

2010-170
During what season is rotavirus the major cause of acute diarrhea in the United States?
Winter, although a new vaccine is significantly reducing cases of rotavirus

2010-170
What is the pathophysiology of the diarrhea caused by rotavirus?
Atrophy and destruction of intestinal villi lead to decreased absorption of sodium and water; remember: ROTA = Right Out The Anus

2010-170
In what settings are rotavirus diarrhea commonly seen?
Daycare centers and kindergartens

2010-170
Globally, what is the most important cause of infantile gastroenteritis?
Rotavirus

2010-170
The recombination of human flu A virus with swine flu A virus is an example of what?
Genetic shift, the reassortment of viral genome, which can cause worldwide pandemics

2010-170
Influenza virus is _____ (enveloped/nonenveloped), with _____-_____ (single-stranded/double-stranded), _____ (segmented/nonsegmented) RNA.
Enveloped; single-stranded; segmented

2010-170
If influenza results in fatal illness, which complication is usually responsible?
Pneumonia caused by bacterial superinfection

2010-170
What are the functions of hemagglutinin and neuraminidase?
Hemagglutinin promotes viral entry and neuraminidase promotes the release of viral progeny

2010-170
Name the two major antigens of the influenza virus.
Hemagglutinin and neuraminidase

2010-170
What is the major mode of protection against influenza virus?
Killed virus vaccine; the vaccine is reformulated each year

2010-170
Genetic shift causes (epidemics/pandemics) _____ while genetic drift causes (epidemics/pandemics) _____.
Pandemics, epidemics; remember: Sudden Shift is more deadly than graDual Drift

2010-170
Random mutations leading to minor genetic changes in the human flu A virus is an example of what?
Genetic drift (antigenic drift)

2010-170
An unvaccinated 4-year-old boy presents with fever, lymphadenopathy, arthralgias and a fine truncal rash. The rash persists for only 3 days. Which viral infection should be suspected?
Rubella

2010-171
Rubella is a relatively benign illness in most cases, but when can serious sequelae result?
When it infects fetuses (it is one of the T0RCH infections)

2010-171
Paramyxoviruses cause disease predominantly in what age group?
Children

2010-171
Injections of which monoclonal antibody are given to children at high risk of severe respiratory syncytial virus bronchiolitis?
Palivizumab

2010-171
What surface protein is common to all paramyxoviruses? What is its role?
Surface F (fusion) protein, which causes respiratory epithelial cells to fuse and form multinucleated cells

2010-171
What diseases are caused by paramyxoviruses?
Mumps, measles, croup and respiratory syncytial virus bronchiolitis

2010-171
What is the typical clinical presentation of croup?
A seal-like barking cough

2010-171
What oral mucosal finding is pathognomonic for measles?
Koplik spots (red spots with blue/white center) on the buccal mucosa

2010-171
What condition is a severe neurologic sequela of measles, appearing years after rubeola infection?
Subacute sclerosing panencephalitis

2010-171
Measles is marked by the constellation of what three symptoms in addition to Koplik spots and descending rash?
Cough, Coryza, and Conjunctivitis (remember: the "3 C"s")

2010-171
Name two severe immediate sequelae of measles infection.
Encephalitis and giant-cell pneumonia (in immunosuppressed individuals)

2010-171
True or False? The rash associated with measles spreads from the extremities to the truncal regions.
False; the rash spreads from head to toe, not in a centripetal pattern

2010-171
What are the symptoms of mumps?
Parotitis, Orchitis, and aseptic Meningitis (remember: With mumps, your testicles and parotids are the size of POM-poms)

2010-171
What is the importance of postexposure vaccination in rabies?
The disease is universally fatal after symptoms have developed

2010-171
Describe the progression of disease in rabies.
It begins with fever and malaise, develops into agitation, hydrophobia, photophobia, and then paralysis, coma, and death

2010-171
What are Negri bodies?
Cytoplasmic inclusions in neurons infected by rabies virus

2010-171
How does rabies virus invade the central nervous system?
By migrating in a retrograde fashion up the nerve axons

2010-171
What is the shape of the rabies virus capsid?
It is bullet shaped

2010-171
What histologic finding of neurons is characteristic of rabies infection?
Negri bodies

2010-171
What animal bites are most likely to result in rabies infection in the United States?
Bat, raccoon, and skunk bites

2010-171
What is the duration of rabies incubation period after exposure?
Weeks to months; the long incubation period allows for successful vaccination after exposure

2010-171
Arboviruses include members of which viral families?
Flavivirus, Togavirus, and Bunyavirus (remember: Fever Transmitted by Bites)

2010-171
What are arboviruses?
Viruses transmitted by arthropods (remember: ARBOvirus: ARthropod-BOrne virus)

2010-171
Why are hepatitis A and E viruses infectious via the fecal-oral route, whereas hepatitis B, C, and D are not?
Because enveloped viruses (B, C, D) are destroyed by the gut whereas naked viruses (A, E) are not

2010-172
What are two severe long-term sequelae of chronic infection with hepatitis C?
Cirrhosis and carcinoma (remember: Hep C: Chronic, Cirrhosis, Carcinoma Carrier)

2010-172
Which viral enzyme participates in hepatitis B replication?
DNA-dependent DNA polymerase
Which two types of hepatitis are trasmitted through the bowels?
Hep A (primarily fecal-oral) and hep E (enteric) (remember: "the vowels hit your bowels")

2010-172
Infection with which hepatitis virus requires coinfection with hepatitis B virus?
Hepatitis D virus (remember: Hepatitis D is Defective and Dependent on hepatitis B virus coinfection)

2010-172
How does hepatitis B virus convert RNA from DNA and then convert it back to RNA?
It converts RNA from DNA using the host cell RNA polymerase, and then DNA from RNA using its own reverse transcriptase
How is the hepatitis E virus different from the hepatitis A virus?
The hepatitis E virus can cause waterborne epidemics and has a high mortality rate among pregnant women (remember: Hep E: Enteric, Expectant mothers, Epidemics)

2010-172
How is the hepatitis B virus transmitted?
By parenteral, sexual, or maternal-fetal routes (remember: Hepatitis B: Blood borne)

2010-172
How does the number of people with serologic evidence of prior hepatitis A infection compare to the number who have had clinically significant infection?
Most infections are clinically insignificant (remember: Hep A: Asymptomatic, Acute, Alone [no carriers])

2010-172
Which has a worse prognosis: coinfection with hepatitis B and hepatitis D, or superinfection of hepatitis D in a patient with hepatitis B?
Superinfection leads to more severe illness

2010-172
The hepatitis A virus is primarily transmitted via what route?
The fecal-oral route

2010-172
What characteristics do hepatitis B and C have in common?
They are both transmitted by blood, they both have chronic carriers, and they both can cause chronic active hepatitis, cirrhosis, and hepatocellular carcinoma

2010-172
What are the signs and symptoms of hepatitis infection?
Episodic fevers, jaundice, and elevated aspartate aminotransferase and alanine aminotransferase levels

2010-172
How long is the incubation period of the hepatitis B virus?
3 months

2010-172
The clinical course of hepatitis E infection resembles that of what other hepatitis virus?
Hepatitis A

2010-172
The hepatitis E virus is primarily transmitted via what route?
The enteric route (causing water-borne epidemics)

2010-172
Does hepatitis A virus have a short or long incubation period?
Short (3 weeks); there are no chronic carriers of the infection

2010-172
Which hepatitis virus has a reverse transcription capability?
Hepatitis B virus; reverse transcription occurs (DNA from an RNA intermediate) but the virion enzyme is a DNA-dependent DNA polymerase

2010-172
Which patient populations are at high risk for hepatitis C?
Intravenous drug users and posttransfusion patients

2010-172
In the window phase of hepatitis B virus infection, hepatitis B surface antigen tests would be (+/-) _____, hepatitis B surface antibody would be (+/-) _____, and hepatitis B core antibody would be (+/-) _____.
Hepatitis B surface antigen negative; hepatitis B surface antibody negative; hepatitis B core antibody positive

2010-173
The presence of which hepatitis B serologic marker would be seen in an asymptomatic patient in the hepatitis B incubation period?
Hepatitis B surface antigen

2010-173
Which serologic marker detects active hepatitis A infection?
Immunoglobulin M hepatitis A virus antibody

2010-173
What is the significance of hepatitis B envelope antigen?
The level of the envelope antigen in serum is a marker of the infectivity of the patient because it indicates active viral replication

2010-173
What does the presence of hepatitis B e antibody indicate?
Presence of antibodies to the envelope antigen indicates lower transmissibility

2010-173
Which antibody is protective against hepatitis B infection?
Hepatitis B surface antibody

2010-173
What pattern of transaminase elevation is seen in viral hepatitis? In alcoholic hepatitis?
In viral hepatitis, alanine aminotransferase > aspartate aminotransferase; in alcoholic hepatitis, aspartate aminotransferase > alanine aminotransferase

2010-173
Which hepatitis serologic marker is positive during the "window period"?
Hepatitis B core antibody

2010-173
After complete recovery from hepatitis B virus infection, hepatitis B surface antigen tests would be (+/-) _____, hepatitis B surface antibody would be (+/-) _____, and hepatitis B core antibody would be (+/-) _____.
Hepatitis B surface antigen negative; hepatitis B surface antibody positive; hepatitis B core antibody positive

2010-173
Which serologic marker indicates prior infection with and is protective against reinfection with hepatitis A infection?
Immunoglobulin G hepatitis A virus antibody

2010-173
Why does hepatitis B surface antibody appear negative during the window period after hepatitis B virus infection?
Because all available hepatitis B surface antibody is bound to hepatitis B surface antigen, making it undetectable on assay

2010-173
In an individual immunized against hepatitis B virus infection, hepatitis B surface antigen tests would be (+/-) _____, hepatitis B surface antibody would be (+/-) _____ and hepatitis B core antigen would be (+/-) _____.
Hepatitis B surface antigen negative; hepatitis B surface antibody positive; hepatitis B core antibody negative

2010-173
Iin a chronic carrier of hepatitis B virus infection, hepatitis B surface antigen tests would be (+/-) _____, hepatitis B surface antibody would be (+/-) _____ and hepatitis B core antibody would be (+/-) _____.
Hepatitis B surface antigen positive; hepatitis B surface antibody negative; hepatitis B core antigen positive

2010-173
What is the significance of immunoglobulin M hepatitis B core antibody vs immunoglobulin G hepatitis B core antibody on serologic studies?
Regarding hepatitis B virus core antibodies, immunoglobulin M is a marker for recent disease whereas immunoglobulin G is a marker for chronic disease

2010-173
In acute hepatitis B virus infection, hepatitis B surface antigen tests would be (+/-) _____, hepatitis B surface antibody would be (+/-) _____, and hepatitis B core antibody would be (+/-) _____.
Positive; negative; positive (immunoglobulin M hepatitis B core antibody in acute stage, immunoglobulin G hepatitis B core antibody in chronic or recovered phase)

2010-173
What does the continued presence of hepatitis B surface antigen in serum mean?
A chronic infection and carrier status for the patient

2010-173
What process must occur in order for HIV genetic material to be integrated into the host genome?
Reverse transcriptase converts RNA into double-stranded DNA and it is then integrated into the host genome

2010-174
What molecules does HIV bind to on T cells?
CXCR4 and CD4

2010-174
Glycoproteins 41 and 120 are located in the _____ (envelope/matrix/capsid) of HIV.
Envelope

2010-174
People homozygous for mutations of which receptor are immune to HIV infection?
CCR5; HIV cannot invade cells without the presence of CCR5; heterozygosity leads to a slower course of illness

2010-174
What molecules does HIV bind to on macrophages?
CCR5 and CD4

2010-174
The p17 protein is located in the _____ (envelope/matrix/capsid) of HIV.
Matrix

2010-174
The p24gag protein is located in the _____ (envelope/matrix/capsid) of HIV.
Capsid

2010-174
Both the enzyme-linked immunosorbent assay and the Western blot assay are falsely positive in which group of patients?
Babies born to infected mothers, because antibodies to anti-glycoprotein 120 can cross the placenta

2010-174
Which lab technique is used to screen for HIV infection?
Enzyme-linked immunosorbent assay

2010-174
The diagnosis of AIDS is made using what criteria?
Confirmed HIV infection; plus CD4+ cell count < 200/mm³, a CD4 to CD8 ratio < 1.5, or presence of an AIDS-defining illness such as Pneumocystis Jiroveci pneumonia

2010-174
Both the enzyme-linked immunosorbent assay and the Western blot assay for HIV detect the presence of what molecules in serum?
Antibodies

2010-174
Why is HIV diagnosis with enzyme-linked immunosorbent assay not considered conclusive evidence of HIV infection?
Enzyme-linked immunosorbent assay for HIV has a high false-positive rate and low threshold; ie, enzyme-linked immunosorbent assay is sensitive and can rule out disease

2010-174
Which lab technique is used to monitor response to therapy in patients who are HIV positive?
HIV polymerase chain reaction (viral load) tests allow for quantification of viral activity in the body

2010-174
Both the enzyme-linked immunosorbent assay and the Western blot assay are falsely negative in which group of patients?
Those who are newly infected (within first 2 months)

2010-174
In diagnosing HIV, if an enzyme-linked immunosorbent assay is positive, which test is used to confirm the diagnosis?
Western blot is highly specific with a high false-negative rate and a high threshold; it is used to rule in disease after a positive enzyme-linked immunosorbent assay test

2010-174
Opportunistic infections and malignancies usually occur how long after an individual is infected with HIV?
Between 3 and 10 or more years (the immunodeficiency phase)

2010-175
During what two time periods does the CD4+ cell count decrease after HIV infection?
There is a decrease in CD4+ cell count during the acute phase followed by recovery and then a slow decline as the illness progresses

2010-175
What are the four stages of HIV infection?
The Four Fs: Flulike (acute), Feeling fine (latent), Falling count, and Final crisis

2010-175
What is the clinical presentation of acute HIV infection?
Flu-like illness

2010-175
Which AIDS-related opportunistic infections affect the lungs?
Pneumocystis jiroveci pneumonia, tuberculosis, and histoplasmosis

2010-175
Which AIDS-related opportunistic infections affect the brain?
Cryptococcal meningitis, toxoplasmosis, cytomegalovirus encephalopathy, AIDS dementia, progressive multifocal leukoencephalopathy (JC virus)

2010-175
Which AIDS-related opportunistic infection affects the eyes?
Cytomegalovirus retinitis

2010-175
Which AIDS-related opportunistic infections affect the mouth and throat?
Thrush (Candida), herpes simplex virus, cytomegalovirus, and Epstein-Barr virus (oral hairy leukoplakia)

2010-175
Which AIDS-related opportunistic infections affect the skin?
Varicella zoster virus (shingles) and human herpes virus type 8 (Kaposi sarcoma)

2010-175
Which AIDS-related opportunistic infections affect the genitals?
Genital herpes and human papillomavirus (genital warts, and cervical cancer)

2010-175
Which AIDS-related opportunistic infections affect the gastrointestinal tract?
Cryptosporidiosis, Mycobacterium avium-intracellulare complex, cytomegalovirus colitis, Epstein-Barr virus (as gastrointestinal lymphoma), and Isospora belli

2010-175
An HIV-positive patient with a CD4+ count < 50/mm³ is at increased risk for which infections?
Cytomegalovirus retinitis and esophagitis, disseminated Mycobacterium avium intracellulare infection, and cryptococcal meningoencephalitis

2010-175
An HIV-positive patient with a CD4+ cell count < 200/mm³ is at increased risk for which infections?
Pneumocystic pneumonia, reactivation of herpes simplex virus infection, cryptosporidiosis, Isospora infection, and disseminated coccidioidomycosis

2010-175
An HIV-positive patient with a CD4+ cell count < 400/mm³ is at increased risk for which infections?
Oral thrush, tinea pedis, reactivation of zoster, reactivation of tuberculosis, and other bacterial infections

2010-175
An HIV-positive patient with a CD4+ cell count <100/mm³ is at increased risk for which infections?
Candidal esophagitis, toxoplasmosis, and histoplasmosis

2010-175
What four malignancies are associated with HIV?
Kaposi sarcoma, invasive cervical carcinoma, primary central nervous system lymphoma and non-hodgkins lymphoma

2010-175
Kaposi sarcoma is caused by _____, while invasive cervical carcinoma is caused by _____.
Human herpesvirus type 8; human papillomavirus

2010-175
In HIV encephalitis, how does the virus gain access to the central nervous system?
Via infected macrophages

2010-175
What are the histopathologic findings of HIV encephalitis?
Microglial nodules with multinucleated giant cells

2010-175
Why does the β-pleated form of Prion protein cause encephalopathy?
Because it is resistant to degradation and facilitates conversion of more prion protein to the β-pleated (pathologic) form

2010-176
What clinical manifestations does prion accumulation cause?
Spongiform encephalopathy, ataxia, dementia, and death

2010-176
What causes Prion diseases?
Prion protein (PrPc: a normal cellular protein) gets converted into a β-pleated form (PrPsc), which destroys normal tissue

2010-176
_____ is an example of an inherited prion disease; _____ is an example of an acquired prion disease; _____ is an example of a sporadic prion disease.
Gerstmann-Sträussler-Scheinker syndrome; kuru; Creutzfeldt-Jakob disease

2010-176
Which three bacteria are considered dominant flora in the vagina?
Lactobacillus, Escherichia coli, and group B Streptococcus

2010-176
Staphylococcus aureus normally colonizes what part of the body?
The nose

2010-176
In which part of the body are viridans streptococci considered normal flora?
The oropharynx

2010-176
Where in the body is Streptococcus mutans part of the normal dominant flora?
The dental plaque

2010-176
Staphylococcus epidermidis is considered normal flora of what parts of the body?
The skin and nose

2010-176
Which bacteria are considered part of the normal dominant flora of the colon?
Bacteroides fragilis and to a lesser extent, Escherichia coli

2010-176
What two organisms that causes food poisoning are found in contaminated seafood?
Vibrio parahaemolyticus and Vibrio vulnificus

2010-176
Which two organisms cause food poisoning that starts quickly and ends quickly?
Staphylococcus aureus and Bacillus cereus

2010-176
Which gram-negative rod causes food poisoning in undercooked meat?
Escherichia coli

2010-176
Given that symptoms of Staphylococcus aureus food poisoning can begin within an hour, symptoms are caused by what?
Preformed toxins

2010-176
What bacteria cause food poisoning that is associated with contaminated poultry, meat, and eggs?
Salmonella

2010-176
Staphylococcus aureus preformed toxin is found in what types of foods?
Meats, mayonnaise, and custard

2010-176
In addition to causing food poisoning, what other type of infection can Vibrio vulnificus cause?
Wound infections (after contact with shellfish or contaminated water)

2010-176
Which bacteria are associated with food poisoning after consumption of improperly canned foods (ie, bulging cans)?
Clostridium botulinum

2010-176
What gram-positive rod causes food poisoning associated with reheated rice?
Bacillus cereus (remember: Food poisoning from reheated rice? Be serious!)

2010-176
Which bacteria are associated with food poisoning after consumption of reheated meat dishes?
Clostridium perfringens

2010-176
Name eight organisms that can cause bloody diarrhea.
Campylobacter jejuni, Salmonella, Shigella, enterohemorrhagic Escherichia coli, enteroinvasive Escherichia coli, Yersinia enterocolitica, Clostridium difficile, and Entamoeba histolytica

2010-177
Which protozoan causes blood diarrhea as well as liver abscesses?
Entamoeba histolytica

2010-177
What comma- or S-shaped organisms cause bloody diarrhea, grow at 42°C, and are oxidase positive?
Campylobacter jejuni

2010-177
Name eight organisms (bacteria, protozoa and viruses) that can cause watery diarrhea.
Enterotoxigenic Escherichia coli, Vibrio cholerae, Clostridium perfringens, Giardia, Cryptosporidium (in immunocompromised patients), rotavirus, adenovirus, and Norwalk virus

2010-177
What nonlactose-fermenting, motile, gram-negative rod causes bloody diarrhea?
Salmonella

2010-177
Pseudomembranous colitis is caused by which organism?
Clostridium difficile

2010-177
How does enterohemorrhagic Escherichia coli cause bloody diarrhea?
By the invasion of the colonic mucosa

2010-177
Which two protozoa cause significant diarrhea in immunocompetent individuals?
Giardia and Cryptosporidium

2010-177
What comma-shaped organisms cause watery diarrhea characterized by "rice-water" stools?
Vibrio cholerae

2010-177
What organism causes bloody diarrhea and pseudoappendicitis and is associated with outbreaks in day-care centers?
Yersinia enterocolitica

2010-177
What nonlactose-fermenting, nonmotile, gram-negative rod has a low ID50 and causes dysentery?
Shigella

2010-177
Which protozoan can cause significant watery diarrhea in immunocompromised patients but mild disease in immunocompetent hosts?
Cryptosporidium

2010-177
Infection with what organism can cause hemolytic uremic syndrome and a bloody diarrhea that is caused by a Shiga-like toxin?
Enterohemorrhagic Escherichia coli

2010-177
Which viruses can cause watery diarrhea?
Rotavirus, adenovirus, and Norwalk virus

2010-177
Enterotoxigenic Escherichia coli causes traveler's diarrhea by producing what two toxins?
Labile toxins and stabile toxins

2010-177
Which gram-positive bacillus that causes gas gangrene also causes watery diarrhea?
Clostridium perfringens

2010-177
What are the three most common causes of pneumonia in adults 18-40 years of age?
Mycoplasma, Chlamydia pneumoniae, and Streptococcus pneumoniae

2010-177
In aspiration pneumonia, one would expect to see what type of organisms?
Anaerobes

2010-177
Which three pathogens commonly cause atypical pneumonia?
Mycoplasma, Legionella, and Chlamydia

2010-177
What are the five most common causes of pneumonia in adults 40-65 years of age?
Streptococcus pneumoniae, Haemophilus influenzae, anaerobes, viruses and Mycoplasma

2010-177
Which pathogens are usually acquired as a nosocomial pneumonia?
Staphylococci and enteric gram-negative rods, which are rarely acquired in the community

2010-177
What are the two most common causes of pneumonia in neonates?
Group B streptococci and Escherichia coli

2010-177
What are the four most common causes of pneumonia in children 4 weeks to 18 years old?
Viruses (Respiratory syncytial virus), Mycoplasma, Chlamydia pneumoniae, and Streptococcus pneumoniae (remember: Runts May Cough Sputum)

2010-177
Which three pathogens commonly cause pneumonia among alcoholics and intravenous drug users?
Streptococcus pneumoniae, Klebsiella, and Staphylococcus

2010-177
What are the most common causes of pneumonia among the elderly?
Streptococcus pneumoniae, Haemophilus influenzae, gram-negative rods, anaerobes, and viruses

2010-177
Postviral pneumonia is commonly caused by what pathogens?
Staphylococcus and Haemophilus influenzae

2010-177
In addition to common causes, which organisms should be considered in immunocompromised patients with pneumonia?
Staphylococci, gram-negative rods, fungi, viruses, and (in patients with HIV infection) Pneumocystis jiroveci

2010-177
Which bacterium often causes pneumonia in patients with cystic fibrosis?
Pseudomonas

2010-177
What four pathogens commonly cause central nervous system disease in HIV-positive patients?
Cryptococcus, cytomegalovirus, toxoplasmosis (brain abscess), and JC virus (progressive multifocal leukoencephalopathy)

2010-178
In people 6 to 60 years old, what four pathogens are most commonly responsible for causing meningitis?
Neisseria meningitidis, enteroviruses, Streptococcus pneumoniae, and herpes simplex virus

2010-178
In newborns up to 6 months of age, what three pathogens are most commonly responsible for meningitis?
Group B streptococcus, Escherichia coli, and Listeria monocytogenes

2010-178
In people 60 years of age and older, what three pathogens are most commonly responsible for causing meningitis?
Streptococcus pneumoniae, Listeria, and gram-negative rods

2010-178
In children between 6 months and 6 years of age, what four pathogens are most commonly responsible for meningitis?
Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type B, and enteroviruses

2010-178
How has the incidence of bacterial meningitis changed in the past 20 years?
It has decreased due to the use of the Haemophilus influenzae vaccine

2010-178
What five viruses are common causes of meningitis?
Enteroviruses (especially coxsackievirus), herpes simplex virus, HIV, West Nile virus, and varicella zoster virus

2010-178
What cerebrospinal fluid findings are indicative of bacterial meningitis?
Increased pressure, polymorphonuclear leukocyte predominance, increased protein, and decreased sugar

2010-178
What cerebrospinal findings are indicative of viral meningitis?
Normal or increased pressure, lymphocyte predominance, normal or elevated protein and normal sugar

2010-178
What is the difference in cerebrospinal fluid findings between bacterial and fungal/tubercular meningitides?
Both show increased pressure and protein and decreased sugar; however, polymorphonuclear leukocytes are found with bacterial causes, whereas lymphocytes are found with fungal/tubercular causes

2010-178
What cerebrospinal findings are indicative of fungal or tubercular meningitis?
Increased pressure, lymphocyte predominance, increased protein, and decreased sugar

2010-178
Which otherwise unlikely organism can cause osteomyelitis in patients with prosthetic replacement?
Staphylococcus aureus and Staphylococcus epidermidis

2010-178
In general, what is the most common cause of osteomyelitis?
Staphylococcus aureus (assume this cause if there is no other information)

2010-178
What is vertebral osteomyelitis caused by tuberculosis called?
Pott's disease

2010-178
What organism is implicated in osteomyelitis resulting from dog bites or cat scratches?
Pasteurella multocida

2010-178
Osteomyelitis in diabetic and drug-addicted individuals may be caused by what organism?
Pseudomonas aeruginosa

2010-178
What two nonspecific laboratory findings are classically found in osteomyelitis?
Elevated erythrocyte sedimentation rate and C-reactive protein

2010-178
In sexually active people, what pathogen can rarely cause osteomyelitis and, more commonly, septic arthritis?
Neisseria gonorrhoeae

2010-178
In what age group does osteomyelitis most frequently occur?
Children

2010-178
Which otherwise unlikely organism can cause osteomyelitis in patients with sickle cell disease?
Salmonella

2010-178
What is the most common route of urinary tract infection?
Ascent of bacteria from the urethra to the bladder

2010-178
Name seven factors that can predispose patients to urinary tract infections.
Flow obstruction, kidney surgery, catheterization, genitourinary abnormalities, diabetes, and pregnancy

2010-178
What are the symptoms of urinary tract infection?
Dysuria, frequency, urgency and suprapubic pain

2010-178
What are the symptoms of pyelonephritis?
Fever, chills, flank pain, and costovertebral angle tenderness

2010-178
What does a positive leukocyte esterase test indicate on urinalysis?
Bacterial urinary tract infection

2010-178
What is found on urinalysis of a patient with pyelonephritis?
White blood cell casts and red blood cells (hematuria)

2010-178
What is found on urinalysis of a patient with cystitis?
White blood cells but not white blood cell casts, which would indicate kidney pathology

2010-178
Infants with what conditions are more prone to urinary tract infections?
Vesicoureteral reflux and other congenital anomalies of the urinary tract

2010-178
What does a positive nitrite test indicate on urinalysis?
Gram-negative bacterial urinary tract infection

2010-178
How does pyelonephritis develop from a lower urinary tract infection?
Further ascent of bacteria from the bladder to the kidneys

2010-178
Elderly males with what condition are predisposed to urinary tract infections?
Enlarged prostate

2010-178
Why are urinary tract infections 10 times more likely to occur in women than in men?
Women have a short urethra that can be colonized by fecal flora

2010-178
Name seven bacteria that cause UTIs.
Serratia marcescens, Staphlococcus saprophyticus, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa (remember: SSEEK PP)

2010-179
The production of what enzyme by Proteus mirabilis is associated with struvite stones?
Urease; the enzyme makes urine more basic, which promotes struvite stone formation

2010-179
Blue-green pigment and fruity odor characterize which organism that causes urinary tract infection?
Pseudomonas aeruginosa

2010-179
What organism causes nosocomial, drug-resistant urinary tract infection and produces a red pigment?
Serratia marcescens

2010-179
Enterobacter cloacae often causes _____ (community-acquired/nosocomial) urinary tract infection, and it is often _____ (drug susceptible/drug resistant).
Nosocomial; drug resistant

2010-179
The colonies of what leading cause of urinary tract infection show a metallic sheen in eosin methylene blue agar?
Escherichia coli

2010-179
What organism, which is characterized by a large mucoid capsule and viscous colonies, causes urinary tract infection and pneumonia in humans?
Klebsiella pneumoniae

2010-179
In sexually active women, what is the second leading cause of community acquired urinary tract infections?
Staphlococus saphrophyticus

2010-179
If a neonate survives in utero infection of syphilis, how does s/he commonly present?
Notched teeth, saddle nose, short maxilla, and saber shins

2010-179
What rash is commonly associated with neonatal rubella?
A "blueberry muffin" rash

2010-179
An infant presents with encephalitis and vesicular skin lesions. What infection did this infant likely contract during vaginal birth?
Herpes simplex virus type 2

2010-179
What are the ToRCHeS infections?
Toxoplasmosis, Rubella, Cytomegalovirus, Herpes simplex virus and HIV, and Syphilis

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How does HIV commonly present in neonates?
Chronic diarrhea, recurrent infections, and failure to thrive

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How does a pregnant woman with rubella infection commonly present?
With rash, arthritis, and lymphadenopathy

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What are the three congenitally acquired infections in which the mother is usually asymptomatic with the infectious agent?
Cytomegalovirus, toxoplasmosis, and herpes simplex virus type 2

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How does a pregnant woman with syphilis commonly present?
If primary, with chancres; if secondary, with disseminated rash; if tertiary, with cardiac and neurologic symptoms

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An neonate is found to have deafness, cataracts, a patent ductus arteriosus, and pulmonary artery stenosis. What infection did his mother most likely have while the neonate was in utero?
Rubella

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What is the classic triad found in many neonatal Toxoplasma gondii infections?
Chorioretinitis, intracranial calcifications, and hydrocephalus

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What physical findings of the neonate are common to most ToRCHeS infections?
Jaundice, hepatosplenomegaly, growth retardation, and thrombocytopenia

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Aside from the infections in the ToRCHeS mnemonic, what are three other important infectious agents that can pass from mother to fetus?
Streptococcus agalactiae (group B strep), Escherichia coli and Listeria monocytogenes; all are common causes of meningitis in neonates

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What is hand-foot-and-mouth disease?
Vesicular lesions on the extremities and oral mucosa caused by coxsackie A virus

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Describe the rash associated with scarlet fever.
Red and sandpaper-like (accompanied by fever and sore throat)

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Name eight diseases that can cause red rashes in childhood.
Measles, mumps, rubella, roseola (human herpesvirus type 6), scarlet fever (group A strep), parvovirus B19, varicella zoster virus, Coxsackie A

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What are the findings of secondary syphilis?
Fever, lymphadenopathy, condyloma lata, and skin rashes

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What are the findings of lymphogranuloma venereum?
Ulcers, lymphadenopathy, and rectal strictures

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What are the clinical findings in tertiary syphilis?
Tabes dorsalis, gummas, aortitis, Argyll Robertson pupil

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What disease is caused by Haemophilus ducreyi?
Chancroid, characterized by painful, genital ulcers and inguinal lymphadenopathy (remember: Haemophilus ducreyi so painful, you do cry)

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Trichomonas vaginaliscauses what condition in women?
Vaginitis; unlike other etiologies of vaginitis, trichomonas is sexually transmitted

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How does the presentation of measles differ from that of rubella?
Measles is preceded by cough, coryza, conjunctivitis and Koplik's spots whereas rubella has a notable postauricular lymphadenopathy

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What organism causes lymphogranuloma venereum?
Chlamydia trachomatis serotypes L1 through L3

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What spirochete causes a painless chancre?
Treponema pallidum (primary stage)

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Characterize the disease caused by Chlamydia trachomatis (serotypes D-K).
Urethritis, cervicitis, pelvic inflammatory disease; neonates can develop conjunctivitis; susceptible individuals can develop reactive arthritis (Reiter syndrome)

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A 2-year-old patient has a high fever for 3 days. On the fourth day, the temperature returns to normal, but the child develops a body-wide red rash. What is the diagnosis?
Human herpesvirus type 6

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How does gonorrhea present in men and women?
In both, urethritis with creamy purulent discharge; in women, cervicitis, pelvic inflammatory disease; in men, prostatitis, epididymitis; disseminated disease can cause migratory arthritis and skin pustules

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Which viral hepatitis can be sexually transmitted?
Hepatitis B

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How do the lesions of chickenpox differ from those of smallpox?
In chickenpox the lesions are in various stages of healing; in smallpox all lesions are of the same age

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What causes condyloma acuminata?
Human papillomavirus types 6 and 11

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In addition to painful genital lesions, herpes simplex virus type 2 commonly causes what systemic symptoms?
Headaches, fevers, myalgias

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What three findings are indicative of bacterial vaginosis?
Noninflammatory discharge, fishy odor (positive whiff test), and clue cells on microscopy

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Name four possible sequelae of pelvic inflammatory disease.
Salpingitis, endometritis, hydrosalpinx, and tubo-ovarian abscess

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Cervical motion tenderness is most commonly associated with what disease?
Pelvic inflammatory disease due to ascending chlamydial or gonorrheal infection

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What is Fitz-Hugh-Curtis syndrome?
Ascending gonorrheal or chlamydial infection causing inflammation of the liver capsule and "violin string" adhesions of the parietal peritoneum to the liver

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What cause of vaginitis shows motile organisms on wet preparations?
Trichomonas vaginalis

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What is the chandelier sign?
Cervical motion tenderness; said to be so painful that the patient jumps up to the ceiling (the chandelier)

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Salpingitis is a risk factor for which complications?
Adhesions, which lead to ectopic pregnancy, infertility, and chronic pelvic pain

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Pelvic inflammatory disease is most often caused by what two organisms?
Chlamydia trachomatis and Neisseria gonorrhoeae

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What is the most common sexually transmitted disease in the United States?
Chlamydia trachomatis; unlike gonorrhea it can be an asymptomatic infection and therefore has higher prevalence

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How does the presentation of urethritis due to gonorrhea differ from that due to chlamydia?
Neisseria gonorrhoeae often causes acute disease with high fevers

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Which nosocomial infection can cause blue-green pus to develop in burn wounds?
Pseudomonas aeruginosa (remember: presume Pseudomonas AIRuginosa when AIR or burns are involved)

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What are the two most common causes of nosocomial infections?
Escherichia coli (urinary tract infection) and Staphylococcus aureus (wound infections)

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Water aerosols that lead to nosocomial infections often involve which organism?
Legionella (remember: think Legionella when water sources are mentioned)

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Hepatitis B virus is associated with nosocomial infections in what setting?
The renal dialysis unit, due to the frequency of venipuncture in that setting

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What etiology of pneumonia, uncommon outside of cystic fibrosis patients, can be acquired from respiratory therapy equipment?
Pseudomonas aeruginosa (remember: presume Pseudomonas AIRuginosa when AIR or burns are involved)

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Which two pathogens are most likely to cause nosocomial infections associated with urinary catheterization?
Escherichia coli and Proteus mirabilis

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What organism is associated with infection of intravenous lines used for hyperalimentation?
Candida albicans

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Cytomegalovirus and respiratory syncytial virus are often associated with transmission in what nosocomial setting?
The newborn nursery

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How do HIV-positive adults with invasive aspergillosis (caused by Aspergillus fumigatus) commonly present?
With pleuritic chest pain, hemoptysis, and an abnormal chest x-ray

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What organism causes tuberculosis-like disease in patients with CD4+ cell count < 50 cells/mm³?
Mycobacterium avium-intracellulare

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What is Kaposi sarcoma?
A malignant neoplasm of superficial vascular endothelial cells caused by human herpesvirus type 8 in HIV-positive individuals

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Which HIV-positive patients are susceptible to pneumonia caused by Pneumocystis jiroveci?
Those with a CD4+ cell count < 200 cells/mm³

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How do HIV-positive adults with Histoplasma capsulatum infection present?
Low-grade fever, cough and hepatosplenomegaly; immunocompetent individuals would have only pulmonary symptoms, if any

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What finding in the stool suggests Cryptosporidium infection?
Acid-fast cysts

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Which virus, which is usually not significant in healthy individuals, causes interstitial pneumonia in AIDS patients?
Cytomegalovirus

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How does the superficial vascular proliferation of Kaposi sarcoma differ from bacillary angiomatosis histologically?
Bacillary angiomatosis is marked by neutrophilic inflammation whereas Kaposi sarcoma is a malignant neoplasm with lymphocytic inflammation

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What diagnosis should be considered in an HIV-positive patient found to have cotton wool spots on fundoscopic exam?
Cytomegalovirus retinitis

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What type of lymphoma is caused by Epstein-Barr virus in patients who are HIV positive?
Non-Hodgkin's lymphoma (large cell)

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What is bacillary angiomatosis?
Vascular proliferation with neutrophilic inflammation seen in HIV-positive individuals infected with Bartonella

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What is Waldeyer's ring?
An area where non-Hodkin's lymphoma caused by Epstein-Barr virus commonly occurs in patients who are HIV positive

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How do HIV-positive adults with Candida albicans infection commonly present?
With fluffy, cottage-cheese lesions on the buccal mucosa (thrush)

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What does biopsy of interstitial pneumonia caused by cytomegalovirus reveal on histology?
Cells with inclusion bodies both in the cytoplasm and nucleus

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Which oral premalignant lesion is caused by Epstein-Barr virus in HIV-positive individuals?
Oral hairy leukoplakia (found on the lateral tongue)

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What causes progressive multifocal leukoencephalopathy?
In AIDS patients, latent JC virus reactivates and causes demyelination

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How does an HIV-positive adult with Cryptosporidium infection commonly present?
With chronic, watery diarrhea

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What male patient population gets squamous cell carcinoma caused by human papillomavirus? Where does it often occur?
Anal squamous cell cancer is more common in HIV-positive men who have sex with men

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Which yeast commonly causes meningitis and encephalitis in adults who are HIV positive?
Cryptococcus neoformans

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Which cause of bacterial meningitis is much more common in unvaccinated children?
Haemophilus influenzae

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What type of diseases does poliovirus cause in unimmunized children?
Meningitis, myalgia, and paralysis

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An unvaccinated child presents with grey exudate in the throat and subsequently develops cardiac and neurologic symptoms. What is your diagnosis?
Corynebacterium diphtheriae infection

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An unvaccinated child presents to the emergency department appearing very ill. He refuses to swallow, drools, and has difficulty breathing. What is your diagnosis?
Epiglottitis caused by Haemophilus influenzae

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In an unvaccinated child with a rash progressing from head to toe, what further information is needed to make a diagnosis?
If the child has lymphadenopathy, it is more likely rubella; if the patient has cough, conjunctivitis, and coryza, it is more likely measles

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What kind of disease does Haemophilus influenzae cause in unimmunized children?
Epiglottis most commonly

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If all else fails, what organism is most likey to be found in a dog or cat bite?
Pasteurella multocida

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If all else fails, what organism is most likely involved in a traumatic open wound infection?
Clostridium perfringens

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If all else fails, what infection is characterized by currant jelly sputum?
Klebsiella

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If all else fails, what organism is most likely when pus, empyema, or abscess is present?
Staphylococcus aureus

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If all else fails, what organism is most likely to be involved in an infection in a patient with chronic granulomatous disease?
Catalase-positive microbes: Staphylococcus aureus, Nocardia, Serratia, Pseudomonas, Aspergillus

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If all else fails, what organism is most likely to be involved in a fungal infection in a diabetic?
Mucor or Rhizopus

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If all else fails, what organism most likely causes bilateral Bell's palsy?
Borrelia burgdorferi in Lyme disease

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If all else fails, what organism is most likely in pediatric infection, including epiglottitis?
Haemophilus influenzae

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If all else fails, what organism is most likely in an infected surgical wound?
Staphylococcus aureus

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If all else fails, what organism is most likely to be involved in burn wound infection?
Pseudomonas aeruginosa

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If all else fails, what organism is most likely to be involved in a needle-stick injury to a healthcare provider?
Hepatitis B virus, which is much more transmissible than HIV or hepatitis C virus via needle stick

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If all else fails, what organism is most likely when a patient with cystic fibrosis develops pneumonia?
Pseudomonas aeruginosa

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If all else fails, what organism is most likely to be involved in an oral infection with "sulfur granules" or branching rods on microscopy?
Actinomyces israelii

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If all else fails, what organism is most likely to be involved in newborn sepsis or meningitis?
Group B Streptococcus

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If all else fails, what organism is most likely to be involved in an infection in an asplenic patient?
Any of the encapsulated bacteria, especially Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitides (remember: SHiN)

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If all else fails, what organism causes systemic disease in neutropenic patients?
Candida albicans

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