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Function and chemical composition of bacterial structure: Peptidoglycan
Function:
1. Rigid support
2. Protects against osmotic pressure

Chemical composition:
Sugar backbone with cross-linked peptide side chains
Function and chemical composition of bacterial structure: Cell wall/cell membrane
Gram positives only

Function: Major surface antigen

Chemical composition: Teichoic acid, which induces TNF and IL-1
Function and chemical composition of bacterial structure: Outer membrane
Gram negatives only

Function: Site of endotoxin (lipopolysaccharide) and major surface antigen

Chemical composition: Lipid A induces TNF and IL-1, and polysaccharide is the antigen
Function and chemical composition of bacterial structure: Plasma membrane
Function: Site of oxidative and transport enzymes

Chemical composition: Lipoprotein bilayer
Function and chemical composition of bacterial structure: Ribosome
Function: Protein synthesis

Chemical composition: 50S and 30S subunits
Function and chemical composition of bacterial structure: Periplasm
Function: Space between the cytoplasmic membrane and outer membrane in gram-negative bacteria

Chemical composition: Contains many hydrolytic enzymes, including beta-lactamases
Function and chemical composition of bacterial structure: Capsule
Function: Protects against phagocytosis

Chemical composition: Polysaccharide (except Bacillus anthracis which contains D-glutamate)
Function and chemical composition of bacterial structure: Pilus/fimbria
Function: Mediates adherence of bacteria to cell surface; sex pilus forms attachment between 2 bacteria during conjugation

Chemical composition: Glycoprotein
Function and chemical composition of bacterial structure: Flagellum
Function: Motility

Chemical composition: Protein
Function and chemical composition of bacterial structure: Spore
Function: Provides resistance to dehydration, heat, and chemicals

Chemical composition: Keratin-like coat and dipicolinic acid
Function and chemical composition of bacterial structure: Plasmid
Function: Contains a variety of genes for antibiotic resistance, enzymes, and toxins

Chemical composition: DNA
Function and chemical composition of bacterial structure: Glycocalyx
Function: Mediates adherence to surfaces, especially foreign surfaces (eg indwelling catheters)

Chemical composition: Polysaccharide
Function of this structure: IgA proteases
Function: Allow some organisms to colonize mucosal surfaces
Which bacteria have IgA proteases?
1. Streptococcus pneumoniae
2. Neisseria meningitidis
3. Neisseria gonorrheae
4. Hemophilus influenzae
Which bacterial substances induce cytokines, and which are they?
Cytokines induced:
1. IL-1
2. TNF

Gram positive inducer: Teichoic acid

Gram negative inducer: Lipopolysaccharide (Endoxtoxin)
What does the capsule of Bacillus anthracis consist of?
D-glutamate
What bacterial structure contains D-glutamate?
Capsule of Bacillus anthracis
What are the main differences between gram negative and gram positive organisms?
Peptidoglycan cell wall: Gram positive has thick. Gram negative has thin.

Flagellar basal body rings: Gram positive has two. Gram negative has four.

Outer antigen: Gram positive: Teichoic acid. Gram negative: Lipidpolysaccharide

Periplasmic space: Gram positive does not have. Gram negative has.

Porin channel: Gram positive does not have. Gram negative has.

Lysozyme and penicillin attack: Gram positive are sensitive. Gram negative are resistant.
What bacteria do not gram stain well?
Mnemonic: These Rascals May Microscopically Lack Color

1. Treponema
2. Rickettsia
3. Mycobacteria
4. Mycoplasma
5. Legionella pneumophila
6. Chlamydia
Why does the following bug not gram stain well?: Treponema
Too thin to be visualized
Why does the following bug not gram stain well?: Rickettsia
Intracellular parasite
Why does the following bug not gram stain well?: Mycobacteria
high-lipid-content cell wall
Why does the following bug not gram stain well?: Mycoplasma
No cell wall
Why does the following bug not gram stain well?: Legionella pneumophila
Primarily intracellular
Why does the following bug not gram stain well?: Chlamydia
Intracellular parasite which lacks muramic acid in cell wall
How is the following bug visualized?: Treponema
1. Darkfield microscopy
2. Fluorescent antibody staining
3. silver stain
Why does the following bug not gram stain well?: Mycobacteria
Acid fast for high lipid content cell wall
What are the stages of bacterial growth and what are their relative lengths?
1. Lag phase: x
2. Log phase: 1.5x
3. Stationary phase: 2.5x
4. Death phase: 4x
What happens in the following phase of bacterial growth, and where does it fall in the order?: Lag
1st phase: Metabolic activity without division
What happens in the following phase of bacterial growth, and where does it fall in the order?: Log
2nd phase: Rapid cell division
What happens in the following phase of bacterial growth, and where does it fall in the order?: Stationary
3rd phase: Nutrient depletion slows growth
What happens in the following phase of bacterial growth, and where does it fall in the order?: Death
4th phase: Prolonged nutrient depletion and buildup of waste products leads to death
Bacterial endotoxins and exotoxins: Source?
Exotoxin: Certain species of gram positive and gram negative bacteria

Endotoxin: Cell wall of most gram-negative bacteria
Bacterial endotoxins and exotoxins: Secreted from cell?
Exotoxin: Yes

Endotoxin: No
Bacterial endotoxins and exotoxins: Chemistry
Exotoxin: Polypeptide

Endotoxin: Lipopolysaccharide
Bacterial endotoxins and exotoxins: Location of genes
Exotoxin: Plasmid or bacteriophage

Endotoxin: Bacterial chromosome
Bacterial endotoxins and exotoxins: Toxicity (fatal dosage)
Exotoxin: High (fatal dose on the order of 1 microgram)

Endotoxin: Low (fatal dose on the order of hundreds of micrograms)
Bacterial endotoxins and exotoxins: Clinical effects
Exotoxin: Toxin specific

Endotoxin: Fever and shock
Bacterial endotoxins and exotoxins: Mode of action
Exotoxin: Toxin specific

Endotoxin: Includes TNF and IL-1
Bacterial endotoxins and exotoxins: Antigenicity
Exotoxin: Induces high-titer antibodies called antitoxins

Endotoxin: Poorly antigenic
Bacterial endotoxins and exotoxins: Vaccines
Exotoxin: Toxoids used as vaccines

Endotoxin: No toxoids formed and no vaccine available
Bacterial endotoxins and exotoxins: Heat stability
Exotoxin: Destroyed rapidly at 60 degrees celsius (except Staphylococcal enterotoxin)

Endotoxin: Stable at 100 degrees celsius for 1 hour
Bacterial endotoxins and exotoxins: Typical diseases
Exotoxin: Tetanus, botulism, diphtheria

Endotoxin: Meningococcemia, sepsis by gram negative rods
Mechanism of superantigens
1. Bind directly to MHC II and T cell receptor
2. Large numbers of T cells are activated.
3. Stimulates release of IFN-gamma and IL-2
Mechanism of ADP ribosylating A-B toxins
Interfere with host cell function

1. B (binding) component binds to a receptor on surface of host cell.
2. The toxin is endocytosed.
3. A (active) component attaches an ADP-ribosyl to a host cell protein.
4. That protein's function is altered.
List of bugs that release superantigens
1. Staphylococcus aureus
2. Streptococcus pyogenes
List of bugs that release ADP ribosylating A-B toxins
1. Corynebacterium diphtheriae
2. Vibrio cholerae
3. E. coli
4. Bordetella pertussis
What to know about exotoxins released by Staphylococcus aureus
Superantigens
1. TSST-1 causes toxic shock syndrome (fever, rash, shock).
2. Enterotoxins cause food poisoning.
What to know about exotoxins released by Streptococcus pyogenes
Scarlet fever (superantigen)
1. Erythrogenic
2. Causes toxic shock-like syndrome

Streptolysin O (hemolysin). The antigen for ASO antibody is found in rheumatic fever
What to know about exotoxins released by Corynebacterium diphtheriae
ADP ribosylating A-B toxin (similar to Pseudomonas exotoxin A)

Encoded by beta-prophage

Disease: Pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy

Mechanism:
Inactivates elongation
factor 2 (EF-2)

Mnemonic: ABCDEFG
ADP ribosylation
Beta-prophage
Corynebacterium
Diphtheriae
Elongation Factor 2
Granules (metachromatic)
What to know about exotoxins released by Vibrio cholerae
1. A-B toxin ADP ribosylates Gs protein thus:
2. Permanently activates Gs protein
3. Constant stimulation of adenylyl cyclase which:
4. Increases pumping of Cl into gut
5. H2O follows it
6. Leads to rice water diarrhea
What to know about exotoxins released by E. coli
E.coli 0157:H7 produces Shiga toxin.

ADP ribosylating A-B toxins

Heat-labile: Permanent activation of adenylyl cyclase (cholera-like mechanism) leading to watery diarrhea

Heat-stabile: Stimulates guanylate cyclase

Mnemonic: Labile like the Air, Stabile like the Ground.
What to know about exotoxins released by Bordetella pertussis
1. ADP ribosylating A-B toxin
2. Permanently disables Gi
3. Constant stimulation of adenylate cyclase
4. Causes whooping cough
5. Also inhibits chemokine receptor causing lymphocytosis
What to know about exotoxins released by Clostridium perfringens
alpha toxin (aka lecithinase) causes:
1. gas gangrene
2. myonecrosis
3. hemolysis (See double zone of hemolysis on blood agar.)

PERFringens PERForates a gangrenous leg.
What to know about exotoxin released by Clostridium botulinum
Properties:
1. Preformed
2. Heat-labile

Mechanism:
Blocks the release of acetylcholine causing:
1. anticholinergic symptoms
2. CNS paralysis (especially cranial nerves)
3. Floppy baby syndrome

BOTulinum is from bad BOTtles of food and honey and sausage (causes flaccid paralysis)
What to know about exotoxins released by Clostridium tetani
Blocks the release of inhibitory neurotransmitter glycine from Renshaw cells in the spinal cord. Causes "lockjaw"
What to know about exotoxins released by Bacillus anthracis
1 toxin in the toxin complex is edema factor, an adenylate cyclase
What to know about exotoxins released by Shigella
Shiga toxin (also produced by E.coli 0157:H7).

Cleaves host cell rRNA. Also enhances cytokine release causing hemolytic uremic syndrome.
Endotoxin: What is it and where is it found?
Lipopolysaccharide found in the outer membrane of gram-negative bacteria. Heat stable.
Endotoxin: What does it activate and what do they release?
1. Macrophages (IL-1, TNF, Nitric oxide)
2. Alternative complement pathway (C3a, C5a)
3. Hageman factor (Coagulation cascade)
What mediators are released when endotoxin activates macrophages, and what do they do?
1. IL-1: Fever
2. TNF: Fever and Hemorrhagic tissue necrosis
3. Nitric Oxide: Hypotension (shock)
What mediators are released when endotoxin activates the alternative complement cascade, and what do they do?
1. C3a: Hypotension and edema
2. C5a: Neutrophil chemotaxis
What mediators are released when endotoxin activates Hageman factor, and what do they do?
Coagulation cascade: Disseminated intravascular coagulopathy
What method is used to differentiate Neisseria?
Sugar fermentation
What do meningococci ferment?
MeninGococci ferment Maltose and Glucose
What do gonococci ferment?
Gonococci ferments Glucose
What are the pigment producing bacteria and what pigments do they produce?
Staphylococcus aureus: Yellow pigment (Aureus means gold in Latin)

Pseudomonas aeruginosa: blue-green pigment

Serratia marcescens: red pigment (think red maraschino cherries)
Special culture requirements for: Hemophilus influenzae
Chocolate agar with factors V (NAD) and X (hematin)

Mnemonic: When a child has "flu" mom goes to five (V) and dime (X) to buy some chocolate.
Special culture requirements for: Neisseria gonorrhoeae
Thayer-Martin media
Special culture requirements for: Bordetella pertussis
Bordet-Gengou (potato) agar
Special culture requirements for: M. tuberculosis
Lowenstein-Jensen agar
Special culture requirements for: Lactose-fermenting enteric bacteria
Pink colonies on MacConkey's agar
Special culture requirements for: Legionella
Charcoal yeast extract agar buffered with increased iron and cysteine
Special culture requirements for: Fungi
Sabouraud's agar
What microbes can be stained with: Congo red
Amyloid. Apple-green birefringence in polarized light (because of beta-pleated sheets)
What microbes can be stained with: Giemsa's
1. Borrelia
2. Plasmodium
3. Trypanosomes
4. Chlamydia
What microbes can be stained with: periodic acid-Schiff (PAS)
Glycogen and mucopolysaccharides. Used to diagnose Whipple's disease
What microbes can be stained with: Ziehl-Neelsen
Acid-fast bacteria.
What microbes can be stained with: India ink
Cryptococcus neoformans
What microbes can be stained with: Silver stain
1. Fungi
2. PCP (Pneumocystis Pneumonia)
3. Legionella
4. Treponema
For the following genetic transfer procedure, explain the process: Conjugation
Direct cell to cell DNA transfer
For the following genetic transfer procedure, explain the process: Transduction
Phage-mediated cell to cell DNA transfer
For the following genetic transfer procedure, explain the process: Transformation
Purified DNA taken up by a cell
For the following genetic transfer procedure, explain the processd: Transposition
DNA transfer to same or another chromosome or plasmid WITHIN a cell
For the following genetic transfer procedure, give the types of cells involved: Conjugation
Prokaryotic
For the following genetic transfer procedure, give the types of cells involved: Transduction
Prokaryotic
For the following genetic transfer procedure, give the types of cells involved: Transformation
Prokaryotic or eukaryotic
For the following genetic transfer procedure, give the types of cells involved: Transposition
Prokaryotic or eukaryotic
For the following genetic transfer procedure, give the nature of DNA transferred: Conjugation
Chromosomal or plasmid
For the following genetic transfer procedure, give the nature of DNA transferred: Transduction
Generalized transduction: Any gene

Specialized transduction: Only certain genes
For the following genetic transfer procedure, give the nature of DNA transferred: Transformation
Any DNA
For the following genetic transfer procedure, give the nature of DNA transferred: Transposition
DNA sequences "jumping genes"
What is lysogeny?
When the genetic code for a bacterial toxin is encoded in a lysogenic phage.
Name 4 lysogenic toxins.
BCDE

1. Botulinum
2. Cholera
3. Diphtheria
4. Erythrogenic toxin of Streptococcus Pyogenes
List four obligate aerobes.
Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Bacillus

Mnemonic: Nagging Pests Must Breathe
Where in the lung does M. tuberculosis prefer, and why?
Apices of the lung, as they have the highest PO2.
What conditions occur concurrently with P. Aeruginosa infection?
1. Burn wounds
2. Nosocomial pneumonia
3. Pneumonias in Cystic Fibrosis patients
List 3 obligate anaerobes
Clostridium, Bacteroides, and Actinomyces
What enzymes do obligate anaerobes lack?
Catalase (aka glutathione peroxidase)

AND/OR

Superoxide dismutase (converts O2-radical[ie superoxide] to H2O2)
Why are anaerobes foul-smelling?
They produce short-chain fatty acids.
What do anaerobes produce in tissue?
CO2 and H2 gases
Where are anaerobes normal flora?
1. GI tract
2. Between teeth and gums
What antibiotics are particularly ineffective against anaerobes?
AminO2glycosides, as they require O2 to enter the bacterial cell.
List the obligate intracellular bacteria.
Rickettsia and Chlamydia.

Mnemonic: Stay inside (cells) when it is Really Cold
What is the defining characteristic of obligate intracellular bacteria.
Can't make their own ATP.
List the facultative intracellular bacteria.
Mnemonic: Some Nasty Bugs May Live FacultativeLY

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia

OR

Mnemonic: My Liege, Your Niece Lists Frank, Bruce and Sam.

Mycobacterium, Leigonella, Yersinia, Neisseria, Listeria, Francisella, Brucella, Salmonella.
List four major examples of encapsulated bacteria
1. Streptococcus pneumoniae
2. Hemophilus influenzae (especially B serotype)
3. Neisseria meningitidis
4. Klebsiella pneumoniae
What does a positive quellung reaction indicate?
Positive quellung: If encapsulated bug is present, capsule swells when specific anticapsular antisera are added.

Mnemonic: Quellung = capsular "swellung"
In which vaccines does the capsule serve as an antigen?
Pneumovax, H influenzae B, Meningococcal vaccines
What does conjugation with protein do to vaccines that have a capsular antigen?
Increases the immunogenicity and T-cell dependent responce.
Which bacteria form spores?
Gram positive soil bugs (eg Bacillus anthracis, Clostridium perfringens, Clostridium tetani)
How can one destroy spores?
Autoclave (as is done to surgical equipment)
Which bacteria are alpha hemolytic?
Streptococcus (all catalase-negative)

If optochin sensitive, bile soluble, or quellung positive: Streptococcus Pneumoniae

If optochin resistant, bile insoluble, or quellung negative: Streptococcus Viridans (eg S. Mutans)
Which bacteria are beta-hemolytic?
Rods:
Listeria monocytogenes

Cocci:
If catalase positive and coagulase positive: Staphylococcus Aureus

If catalase negative, Streptococcus.
Then, if bacitracin sensitive, S. pyogenes. If bacitracin resistant, S. agalactiae.
What are the important points about Listeria monocytogenes?
1. Tumbling motility
2. Meningitis in newborns
3. Unpasteurized milk
Gram positive: Which are catalase positive and which are catalase negative?
Positive: Staph
Negative: Strep
Gram positive: Which are catalase positive bacteria make coagulase?
Staph aureus does.

Staph epidermidis and saprophyticus do not.
What is Protein A?
Virulence factor of Staphylococcus Aureus. Binds Fc-IgG, inhibiting complement fixation and phagocytosis.
What disease states does Staphylococcus Aureus cause?
Inflammatory:
1. Skin infections
2. Organ abscesses (acute bacterial endocarditis, osteomyelitis)
3. Pneumonia

Toxin-mediated:
1. Toxic shock syndrome (TSST-1)
2. Scalded skin syndrome (exfoliative toxin)
3. Rapid-onset food poisoning (ingestion of preformed enterotoxin)
What disease states does Streptococcus Pyogenes cause?
Pyogenic
1. Pharyngitis
2. Cellulitis
3. Impetigo

Toxigenic
1. Scarlet fever
2. Toxic shock syndrome

Immunologic
1. Rheumatic fever
2. Acute glomerulonephritis
What are two sequelae of Streptococcus Pyogenes pharyngitis?
Rheumatic fever and acute glomerulonephritis

Mnemonoic: PHaryngitis gives you rheumatic PHever and glomerulonePHritis
Which antibody enhances host defenses against Streptococcus Pyogenes?
Antibody to M protein
Antibody to M protein enhances host defenses against what?
Streptococcus Pyogenes
What does ASO titer detect?
Recent S. Pyogenes infection
How can one detect recent S. Pyogenes infection?
ASO titer
What are the signs and symptoms of rheumatic fever?
1. Subcutaneous nodules
2. Polyarthritis
3. Erythema marginatum
4. Chorea
5. Carditis (bacterial endocarditis)

Mnemonic: No "rheum" for SPECCulation
What is streptococcus pneumoniae the most common cause of?
1. Meningitis
2. Otitis media (in children)
3. Pneumonia
4. Sinusitis

S. pneumoniae MOPS are Most OPtochin Sensitive
What is the most common cause of meningitis?
Streptococcus pneumoniae
What is the most common cause of otitis media?
Streptococcus pneumoniae
What is the most common cause of pneumonia?
Streptococcus pneumoniae
What is the most common cause of sinusitis?
Streptococcus pneumoniae
What is indicated by "rusty" sputum?
Streptococcus pneumoniae infection
What are common associations with Pneumococcus?
Streptococcus Pneumoniae

1. "Rusty" sputum
2. Sepsis in sickle cell anemia 3. splenectomy
What does sepsin in sickle cell anemia indicate?
Streptococcus pneumoniae
What do Group B streptococci cause?
B for Baby

1. Pneumonia
2. Meningitis
3. Sepsis
3 most common causes of meningitis in infants younger than 3 months of age
1. E. coli
2. Listeria monocytogenes
3. Group B streptococcus
How do infants with meningitis present?
1. Fever
2. Vomiting
3. Poor feeding
4. Irritability
Name the Lancefield Group D bacterial categories and examples of each.
Enterococci:
1. Enterococcus faecalis
2. Enterococcus faecium

Non-enterococci
1. Streptococcus bovis
2. Streptococcus equinus
What is Streptococcus bovis infection a sign of?
Colonic malignancy
What kind of hemolysis do enterococci cause?
Variable

(CMMRS says alpha; FA says variable and gamma)
What drug resistances do the enterococci show?
1. Penicillin G
2. Ampicillin
3. Vancomycin
What is Lancefield grouping determined by?
Differences in the C carbohydrate on the bacterial cell wall
Which Group D bacteria are hardier?
Enterococci are hardier than nonenterococci. They can grow in 6.5% NaCl
A colony of bacteria grows in 6.5% NaCl. What is it?
Enterococcus
What disease states/problems does Staphylococcus epidermidis cause?
Infection of prosthetic devices and catheters. Contaminates blood cultures.
How is Streptococcus Viridans characterized?
1. Alpha hemolysis
2. Optochin resistant
3. Normal mouth flora

(Mnemonic: Viridans lives in the mouth because it is not afraid of-the-chin)
Where is Strep. Viridans part of the normal flora?
Oropharynx
What disease states/problems does Streptococcus Viridans cause?
1. Dental caries (Streptococcus mutans)
2. Subacute Bacterial endocarditis (Streptococcus Sanguis)
What disease states does Streptococcus mutans cause?
Dental caries
What disease states does Streptococcus sanguis cause?
Subacute bacterial endocarditis

Sanguis = blood, lots of blood in the heart.
How are clostridia characterized?
1. Gram positive rods
2. Spore forming
3. Obligate anaerobes
What disease state does Clostridium difficile cause, and what is its mechanism?
Disease state: pseudomembranous colitis secondary to clindamycin or ampicillin use. (Mnemonic: DIfficile causes DIarrhea)

Mechanism:
1. Antibiotic kills off protective flora
2. C. difficile takes hold and proliferates
3. Produces cytotoxin, an enterotoxin.
4. Cytotoxin kills enterocytes.
Treatment for C. difficile infection
Metronidazole
Lab diagnosis basis for Cornyebacterium diphtheriae
Gram positive rods with metachromatic granules, grown on tellurite agar (aka Loffler's coagulated serum medium)
How is Bacillus anthracis characterized?
1. Gram positive rod
2. Spore forming
3. Protein capsule
Which bacteria have a protein capsule?
Bacillus anthracis (the only one)
What are the mechanisms of anthrax infection and disease?
1. Non-inhalation contact with bacillus anthracis
2. Formation of malignant pustule (painless ulcer)
3. Progression to bacteremia
4. Death

1. Inhalation of spores
2. Development of flulike symptoms that rapidly progress to fever, pulmonary hemorrhage and shock.
What organism: Development of flulike symptoms followed by fever, pulmonary hemorrhage and shock.
Inhalation anthrax: Bacillus anthracis
What do skin lesions in anthrax look like?
Vesicular papules covered by black eschar
What is Woolsorter's disease
Inhalation of Bacillus anthracis spores from contaminated wool
What organism: Gram-positive rods forming long branching filaments resembling fungi
Actinomyces israelii or Nocardia asteroides
What organism: Oral or facial abscesses with yellow granules in sinus tracts
Actinomyces israelii
What disease state does Actinomyces israelii cause?
Oral or facial abscesses with yellow granules draining out skin through sinus tracts
How is Actinomyces israelii characterised?
Gram-positive anaerobic rods forming long branching filaments resembling fungi (Nocardia also has this description)

Causes oral or facial abscesses with yellow granules
How is Nocardia asteroides characterized?
Gram-positive (weakly acid fast) rods forming long branching filaments resembling fungi (Actinomyces also has this description)
What disease state does Nocardia asteroides cause?
Pulmonary infection in immunocompromised patients
What is the treatment for Actinomyces israelii?
Penicillin

Mnemonic: SNAP (Sulfa for Nocardia; Acintomyces use Penicillin)
What is the treatment for Nocardia Asteroides?
Sulfonamides

Mnemonic: SNAP (Sulfa for Nocardia; Acintomyces use Penicillin)
Penicillin G and Gram negative bugs
Gram-negatives are resistant to benzyl penicillin G. The gram-negative outer membrane layer inhibits entry of penicillin G and vancomycin.

May be susceptible to penicillin derivatives such as ampicillin.
What bacteria genus can live in neutrophils?
Neisseria
How are neisseria characterized?
Gram-negative cocci that resemble paired coffee beans
Gonococcus and meningococcus: Polysaccharide capsule
G: No
M: Yes
Gonococcus and meningococcus: Maltose fermentation
G: No (Gonococcus ferments Glucose)
M: Yes (MeninGococcus ferments Maltose and Glucose)
Gonococcus and meningococcus: Vaccine availability
G: No
M: Yes
What disease states does Gonococcus cause?
1. Gonorrhea
2. septic arthritis
3. neonatal conjunctivitis
4. PID
What disease states does Meningococcus cause?
1. Meningococcemia
2. Meningitis
3. Waterhouse-Friderichsen syndrome
What is Waterhouse-Friderichsen syndrome?
massive, usually bilateral, hemorrhage into the adrenal glands caused by fulminant meningococcemia.

Characterised by overwhelming bacterial infection, rapidly progressive hypotension leading to shock, disseminated intravascular coagulation (DIC) with widespread purpura, particularly of the skin, and rapidly developing adrenocortical insufficiency associated with massive bilateral adrenal hemorrhage.
What disease states does Haemophilus Influenzae cause?
HaEMOPhilus causes
1. Epiglottitis
2. Meningitis
3. Otitis media
4. Pneumonia

Does not cause flu (that's a virus)!
How is Haemophilus Influenzae characterized?
Small gram-negative coccoid rod.
How is Haemophilus Influenzae transmitted?
Aerosol
Which type of Haemophilus Influenzae is most pathogenic?
capsular type B
Treatment for Haemophilus Influenzae meningitis
Ceftriaxone
Prophylaxis for Hemophilus Influenzae
Vaccine: Type B polysaccharide conjugated to diphtheria toxoid or other protein. Given between 2 and 18 months of age.

Close contacts of infected person: Rifampin
How are enterobacteriaceae characterized?
Gram negative diverse group

Mnemonic: COFFEe

3. Capsule (K [kapsular] antigen related to virulence of the bug)
2. O antigen (somatic antigen which is the polysaccharide of endotoxin)
4. Flagella (H antigen found in motile species)
5. Ferment glucose
6. Enterobacteriaceae (woo!)
Enterobacteriaceae list
1. Escherichia coli
2. Klebsiella pneumoniae
3. Proteus mirablis
4. Enterobacter sp.
5. Serratia
6. Shigella
7. Salmonella
8. Yersinia enterocolitica
What disease states does Klebsiella cause?
1. Pneumonia in alcoholics and diabetics (In the name: Klebsiella pneumoniae)
2. Nosocomial UTIs (large mucoid capsule and viscous colonies)

Mnemonic: AAA (Aspiration pneumonia, Abscess in lungs, Alcoholics)
Signs and symptoms of Klebsiella infection
1. Red currant jelly sputum
2. Abscess in lungs
Orange sputum: What bugs?
1. Pneumococcus
2. Klebsiella (or described as "red currant jelly sputum")
Red currant jelly sputum: What bug?
Klebsiella
Lactose-fermenting enteric bacteria
Mnemonic: Test lactose with MacConKEE’S.

1. Citrobacter
2. Klebsiella
3. E. coli
4. Enterobacter
5. Serratia
Salmonella vs. Shigella: Lactose fermenter?
Neither
Salmonella vs. Shigella: Motile
Both (Though, the evidence that shigella is motile is recent.)

Can invade and disseminate hematogenously.
Salmonella vs. Shigella: Animal reservoir
Salmonella: Yes
Shigella: No
Shigella transmission
4 Fs:
1. Food
2. Fingers
3. Feces
4. Flies
Salmonella vs. Shigella: Virulence
Salmonella: 100,000 organisms
Shigella: 10 organisms
True or False: Salmonellosis symptoms may be prolonged with antibiotic treatments
True
What type of inflammatory response is seen in Salmonellosis?
Monocytes
Transmission of Yersinia enterocolitica
1. Pet feces (eg puppies)
2. Contaminated milk or pork
Yersinia enterocolitica infection: Clinical presentation
1. Outbreaks are common in day-care centers
2. Can mimic Crohn's or appendicitis
What bug causes contamination of this food: Seafood
Vibrio:
1. parahaemolyticus
2. vulnificus
What bug causes contamination of this food: Reheated rice
Bacillus cereus

Mnem: "Food poisoning from reheated rice? Be serious!"
What bug causes contamination of this food: Meat
1. Staphylococcus Aureus (starts quickly and ends quickly)
2. Salmonella (including poultry)
3. Clostridium perfringens (reheated meat dishes)
4. Vibrio (parahaemolyticus, vulnificus) (in seafood)
5. E. coli O157:H7 (undercooked meat)
6. Clostridium Botulinum (in sausage)
What bug causes contamination of this food: Mayonnaise
Staphylococcus Aureus (starts quickly and ends quickly)
What bug causes contamination of this food: Custard
Staphylococcus Aureus (starts quickly and ends quickly)
What bug causes contamination of this food: Reheated meat
Clostridium perfringens

Mnem: "Food poisoning from reheated meat? Clostridium perfringens!"
What bug causes contamination of this food: Bulging cans
Clostridium botulinum

(BOTulinum is from bad BOTtles of food and honey and sausage)
What bug causes contamination of this food: Sausage
Clostridium botulinum

(BOTulinum is from bad BOTtles of food and honey and sausage)
What bug causes contamination of this food: Honey
Clostridium botulinum

(BOTulinum is from bad BOTtles of food and honey and sausage)
What bug causes contamination of this food: Poultry
Salmonella
What bug causes contamination of this food: Eggs
Salmonella
Bloody or watery diarrhea: Vibrio parahaemolyticus
Either bloody or watery
Bloody or watery diarrhea: Campylobacter
Bloody
Bloody or watery diarrhea: Salmonella
Bloody
Bloody or watery diarrhea: Shigella
Bloody
Bloody or watery diarrhea: Enterohemorrhagic E. coli
Bloody
Bloody or watery diarrhea: Enteroinvasive E. coli
Bloody
Bloody or watery diarrhea: Yersinia enterocolitica
Bloody
Bloody or watery diarrhea: C. difficile
Bloody
Bloody or watery diarrhea: Entamoeba histolytica
Bloody
Bloody or watery diarrhea: Enterotoxigenic E. coli
Watery
Bloody or watery diarrhea: Vibrio cholerae
Watery
Bloody or watery diarrhea: C. perfringens
Watery
Bloody or watery diarrhea: Protozoa
Watery
Bloody or watery diarrhea: Viruses
Watery
Diagnosis: Bloody diarrhea with oxidase-positive comma or S-shaped organisms grown at 42 degrees celsius
Campylobacter
Diagnosis: Bloody diarrhea with motile, lactose negative gram negative bugs
Salmonella or Shigella

Shigella have a very low ID50 and cause dysentery
Diagnosis: Bloody diarrhea with schistocytes and azotemia
Enterohemorrhagic E coli (eg O157:H7)

Caused by shiga-like toxin
Diagnosis: Bloody diarrhea with hemolytic uremic syndrome
Enterohemorrhagic E coli (eg O157:H7)

Caused by shiga-like toxin
Diagnosis: Bloody diarrhea with pathologic section revealing bacteria invading colonic mucosa
Enteroinvasive E. coli
Diagnosis: Bloody diarrhea with symptoms of appendicitis
Yersinia enterocolitica
Diagnosis: Bloody diarrhea in a day care center
Yersinia enterocolitica
Diagnosis: Bloody diarrhea with pseudomembranous colitis
Clostridium dificile
Diagnosis: Bloody diarrhea with protozoans
Entamoeba histolytica
Diagnosis: Watery diarrhea in someone who just visited Mexico
Enterotoxigenic E coli (no preformed toxin)
Diagnosis: Watery diarrhea with comma-shaped organisms
Vibrio cholerae
Diagnosis: Watery diarrhea with appearance of rice water
Vibrio cholerae
Diagnosis: Watery diarrhea with gangrenous leg
Clostridium perfringens
Diagnosis: Watery diarrhea in an immunocompromised patient
Protozoa (eg Giardia or Cryptosporidium)
Diagnosis: Watery diarrhea
Think viruses first.

Rotavirus
Adenovirus
Norwalk virus
Difference between mechanisms of cholera and pertussis toxins
Cholera: Permanently activates Gs (turns the "on" on)

Pertussis: Permanently disables Gi (turns the "off" off)
What is edema factor?
A toxin in the Bacillus Anthracis exotoxin complex that functions as adenylyl cyclase
Disease states caused by Legionella (list only)
1. Asymptomatic infection
2. Pontiac fever
3. Legionnaires disease
Describe Pontiac fever
Caused by Legionella. Presents like influenza. Strikes suddenly and completely resolves in one week. Originally described in the Pontiac Michigan government AC.
Describe Legionnaires' disease
Very high fever with severe pneumonia
Treatment for Legionella
Has a beta-lacatamase (penicillin-resistant)

1. Erythromycin
2. Rifampin
Diagnosis: Pneumonia in a smoker >50 years of age. Gram stain of pus shows many neutrophils with few microbes.
Legionella
Special culture requirements for: Legionella
Grows on charcoal yeast extract culture with iron and cysteine
Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with a canteen of water (water transmission) and his iron dagger-he is no sissy (cysteine).
Legionella: Gram stain
Gram negative. Gram stains poorly (use silver stain)


Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with his iron dagger-he is no sissy (cysteine).
Legionella: How transmitted?
Aerosol transmission from environmental water sources (AC, Showers, whirlpools, cooling towers, supermarket produce mist)

Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with a canteen of water (water transmission) and his iron dagger-he is no sissy (cysteine).
Pseudomonas: Disease states
PSEUDDOburnnas
1. Pneumonia (especially in CF)
2. Sepsis (black lesions on skin)
3. External otitis (swimmer's ear)
4. UTI (nosocomial and drug-resistant)
5. Drug use
6. Diabetic Osteomyelitis
7. Burns and wound infections
8. Hot tub folliculitis
Pseudomonas: Organism characterization
1. Gram-negative rod
2. non-lactose fermenting
3. Aerobic (think AERuginosa) and oxidase positive (cytochrome c oxidase for oxidative phosphorylation)
4. Produces pyocyanin (blue-green) pigment
5. Fruity odor
What to know about exotoxins produced by: Pseudomonas aeruginosa
Exotoxin A is an ADP ribosylating A-B toxin (similar to Diphtheria toxin)

Mechanism:
Inactivates elongation
factor 2 (EF-2)

Also has endotoxin (as it is gram negative) which produces fever and shock.
Diagnosis: Sepsis in burn victim
Most likely Pseudomonas
Treatment for pseudomonas
Aminoglycoside

plus

Extended-spectrum penicillin (eg piperacillin, ticarcillin)
Helicobacter pylori: Disease states
Causes:
1. Gastritis
2. 90% of duodenal ulcers

Risk factor for:
1. Peptic ulcer
2. Gastric carcinoma
Helicobacter pylori: Characterization
1. Gram negative rod
2. Urease-positive
3. Creates alkaline environment
Treatment for Helicobacter Pylori
Triple treatment

1. Metronidazole with one of the two combos below

$:
2. Bismuth (eg Pepto-Bismol)
3. Either Tetracycline or Amoxicillin

$$:
2. Omeprazole
3. Clarithromycin
What bug?: Urease-positive gram-negative bacteria
Proteus and H. Pylori
Zoonotic bacteria
1. Borrelia burdorferi
2. Francisella tularensis
3. Yersinia pestis
4. Pasteurella multocida
5. Brucella spp. (Undulant fever from dairy/contact with animals)

Mnemonic: Bugs From Your Pet Undulate and Unpasteurized dairy gives you Undulant fever
Borrelia burgdorferi: Disease states
Lyme disease
Brucella: Disease states
Undulant fever/Brucellosis. Temperature slowly rises during day, peaks in the evening, and slowly declines to normal by morning.

Accompanied by other systemic symptoms.
Brucella: Transmission
from animal contact (meat worker, farmer, veterinarian) or unpasteurized milk
Gross mechanism of brucellosis
1. Penetration of skin (but no buboes or primary skin ulcer), conjunctiva, lungs, GI tract
2. Lymphatic spread
3. Facultative intracellular growth in macrophages, and blood and organ invasion
Francisella Tularensis: Disease states (list)
Tularemia, either:
1. Pneumonic
2. Oculoglandular
3. Ulceroglandular
4. Typhoidal

(Don't POUT when you've got tularemia.)
Describe Ulceroglandular tularemia
a. Well-demarcated hole in the skin with a black base
b. Fever and systemic symptoms
c. Swollen/red/painful purulent lymph nodes

Similar to plague, but with skin ulcer, and low mortality.
Francisella tularensis: Transmission
Most common: Handling of infected rabbits or from bites of ticks and deer flies

Hundred creatures in total all over US.

Mnemonic: Francis the rabbit is playing in the TULips, with a deerfly on one ear and a tick on the other.
Virulence of Francisella tularensis
Very. (10 organisms cause disease.)
Diagnosis of Francisella tularensis
Clinical picture, PPD-like skin test, and titers of Francisella Ig
Yersinia pestis: Transmission
PESTS like rats harbor the disease and fleas are the vector, biting the skin of humans. Found in campers, hunters, and hikers.

Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
Fraction 1 (F1) antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)

Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
V antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)

Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
W antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)

Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
Yersinia pestis: Presentation in humans
1. Lymph node (usually inguinal [boubon is Greek for groin]) becomes inflamed (all four signs).
2. Fever, and headache.
3. Blackish discoloration under skin ("Black death")
Disease states caused by Yersinia pestis
Bubonic plague/pneumonic plague
Pasteurella Multocida: Transmission
Cat, dog, and animal bites. Also infects birds.

Mnemonic: Cat and dog chasing a bird in a "Pasteur".
T/F: All Zoonotic Gram negative bugs are facultative intracellular.
False. Pasteurella is not.
Pasteurella: Treatment
Do not suture wound after dog or cat bite/scratch. (Best breeding ground for Pasteurella)

Treat with penicillin or doxycycline.
Gardnerella: Characterization
Pleomorphic, gram-variable rod.
What disease states does Gardnernella cause?
Vaginosis
1. Greenish vaginal discharge with fishy smell
2. Noninflammatory (nonpainful)
3. Mobiluncus (anaerobe) is also seen
4. Clue cells are visible (vaginal epithelium covered with bacteria)
5. Positive Whiff test
Clue cell, indicative of Gardnerella vaginosis
What is this?
What does a positive PPD indicate?
1. Current infection
2. Past exposure
3. BCG vaccination
What does a negative PPD indicate?
1. No infection
2. Anergy (due to: steroids, immunocompromise, malnutrition), inject candida/mumps vaccine into other arm. If still negative, anergic.
Fast-fermenting lactose bacteria
Fast fermenters: (EEK! Too fast!)
1. E.coli
2. Enterobacter sp.
3. Klebsiella
Slow fermenting lactose bacteria
Slow fermenters:
1. Serratia
2. Citrobacter
3. "Others"
Tuberculosis infection: Gross mechanism
1. Inhaled aerosols from infected adults
2. Land in middle or lower lobes of lung (highest airflow) leading to small area of pneumonitis.
3. Bacteria enter macrophages, multiply, and spread hematogenously.
Mechanism of asymptomatic primary TB
1. Cell-mediated defense walls off foci of bacteria in caseous granulomas
2. Granulomas heal with fibrosis, calcification and scar formation
Difference between Ghon focus and Ghon complex
Ghon focus: Calcified tubercle in the middle or lower lung

Ghon complex: Ghon focus accompanied by perihilar or lobar lymph node calcified granulomas
What is a Ranke complex?
Same as a Ghon complex: Ghon focus accompanied by perihilar or lobar lymph node calcified granulomas
Mechanism of symptomatic primary TB
1. Large caseous granulomas develop in the lungs/other organs.
2. In the lungs, caseous material liquifies, is extruded out the bronchi and leaves cavitary lesions behind.
Mechanism of secondary Pulmonary TB
1. Infection occurs at apical areas of lung around the clavicles due to highest oxygen tension caused by decreased pulmonary circulation.
2. Infected areas grow, caseate, liquify and cavitate.
TB reactivation sites
1. Pulmonary (Lung parenchyma)
2. Pleura
3. Pericardium
4. Scrofula (Cervical lymph nodes: most common extrapulmonary site worldwide)
5. Kidney (Sterile pyuria)
6. Thoracic and lumbar spine (Pott's disease)
7. Chronic monoarthritis
8. CNS (subacute meningitis or parenchymal tuberculoma)
9. Miliary TB (Millet sized tubercles all over the body)
Tuberculosis rule of 5s
1. Droplet nuclei are 5 micrometers and contain 5 mycobacteria
2. 5% risk of reactivation in first 2 years and then 5% lifetime risk
3. Patients with HIV ("High five") have 5+5% yearly reactivation risk.
4. Induration measurements
a. HIV: >5 mm
b. High risk: >5+5 mm
c. Everyone else: >5+5+5 mm
Cause of Miliary tuberculosis
Severe bacteremia
Types of Mycobacteria and what they cause
Mnemonic: Identifying mycobacteria is no Light TASK

Mycobacterium
1. Leprae
2. Tuberculosis
3. Avium-intracellulare
4. Scrofulaceum
5. Kansasii
What disease state does Mycobacterium Avium-intracellulare cause?
bugs are multiple drug resistant and cause disseminated disease in AIDS
Symptoms of tuberculosis
1. Fever
2. Night sweats
3. Weight loss
4. Hemoptysis
Two Langhans type giant cells in which the nuclei are lined up around the periphery of the cell in a horseshoe pattern.

Seen in granulomatous conditions like TB
What is this?
What is Hansen's disease?
leprosy
What is leprosy caused by?
Mycobacterium leprae
Characterization and reservoir of Mycobacterium Leprae
1. Acid fast bacillus
2. Likes cool temperatures
3. Infects skin and superficial nerves
4. Cannot be grown invitro
5. Reservoir: Armadillos
Presentation of lepromatous leprosy
"Leonine facies"
1. Loss of eyebrows
2. Nasal collapse
3. Lumpy earlobe
Treatment for leprosy
Long-term oral dapsone

Alternative: Rifampin, clofazimine, and dapsone
Toxicity of longterm oral dapsone
1. Hemolysis
2. Methemoglobinemia
2 forms of leprosy
1. Lepromatous (Due to failed cell-mediated immunity. Lep. is Lethal)
2. Tuberculoid (self=limiting)
Rickettsiae: Characterization
Obligate intracellular parasites. Need CoA and NAD.
Rickettsiae: Transmission and presentation
Coxiella: Atypical. Transmitted by aerosol and causes pneumonia

All others: Arthropod vector causes classic triad of headache, fever and rash (vasculitis)
Treatment of Rickettsiae
Tetracycline
Difference between spread of rash in typhus and spotted fever
tyPHus is centriPHugal (moves outwards)

sPotted fever is centriPetal (moves inwards)

Both are caused by Rickettsiae
Which bug causes Rocky Mountain spotted fever?
Rickettsia rickettsii, transmitted by tick
Which bug causes endemic typhus?
Rickettsia typhi, transmitted by fleas
Which bug causes epidemic typhus?
Rickettsia prowazekii, transmitted by human body louse
Which bug causes typhus?
Endemic: Rickettsia typhi, transmitted by fleas

Epidemic: Rickettsia prowazekii, transmitted by human body louse
Which bug causes Q fever?
Coxiella burnetii, by inhaled aerosols from cowhide and placentas.

Remember: Carol Burnett coughing "Q" after inhaling spores from cowhide.
What separates Q fever from other rickettsial diseases?
Q fever is Queer. Rickettsial, but has an endospore, thus:

1. Caused by Coxiella burnetii (not called Rickettsia)
2. No rash
3. No vector (inhaled aerosols)
4. Negative Weil-Felix
5. Causative organism can survive outside for a long time.
Difference in tropism between Chlamydia and Rickettsia
Rickettsia: Endothelial cells of blood vessels

Chlamydia: Columnar epithelium
Where is the rash in Rocky Mountain spotted fever found?
Palms and soles, migrating to wrists, ankles, then trunk.
Where can rashes on the palms and soles of feet be seen?
1. Rocky mountain spotted fever
2. Syphilis
3. Coxsackie virus A infection (hand, foot, and mouth disease)
Weil-Felix reaction
Assays for antirickettsial antibodies, which cross-react with Proteus antigen
Typhus: positive or negative Weil-Felix
positive
Rocky mountain spotted fever: positive or negative Weil-Felix
positive
Q fever: positive or negative Weil-Felix
negative
What bug: Atypical walking pneumonia in prisoner or military recruit younger than 30
Mycoplasma pneumoniae
Describe mycoplasma pneumoniae pneumonia
1. Atypical walking pneumonia (insidious onset, headache, non productive cough, diffuse interstitial infiltrate)
2. X-ray looks worse than patient
3. High titer of cold agglutinins (IgM)
Special culture requirements for: Mycoplasma pneumoniae
Eaton's agar
Treatment for mycoplasma pneumoniae
Tetracycline or erythromycin.

Pencillin resistant because they have no cell wall.
Characterization of Mycoplasma pneumoniae
1. Facultative anaerobe with no cell wall (hence no gram stain)
2. Only bacterial membrane with cholesterol
3. High titer of cold agglutinins
4. Grown on Eaton's agar
True or False: No Gram-positive bugs have endotoxin.
False. Listeria monocytogenes has it.
Characterize Chlamydia
Obligate intracellular parasites
2 forms of chlamydia
1. Elementary body (small, dense) which Enters cell via endocytosis

2. Initial or Reticulate body, which Replicates In cell by fission
Disease states caused by Chlamydia trachomatis
1. Reactive arthritis (aka Reiter's syndrome)
2. Conjunctivitis
3. Non-gonococcal urethritis, cervicitis, and PID
Disease states caused by Chlamydia pneumoniae
Atypical pneumonia
Disease states caused by Chlamydia psittaci
Atypical pneumonia
Chlamydia species
1. Trachomatis
2. Pneumoniae
3. Psittaci
What is unusual about the chlamydial wall?
It lacks muramic acid.
Treatment of Chlamydia
Erythromycin or tetracycline
Reservoir for Chlamydia psittaci
Avian
Which chlamydia has an animal reservoir?
Psittaci: Avian
Lab diagnosis of chlamydia
Cytoplasmic inclusions seen on Giemsa or fluorescent-antibody stained smear
What disease is caused by Chlamydia Trachomatis serotypes A-C
1. Chronic infection
2. Blindness in Africa

Mnemonic: ABC: Africa, Blindness, Chronic infection
What disease is caused by Chlamydia Trachomatis serotypes D-K
1. Urethritis/PID
2. Ectopic pregnancy
3. Neonatal pneumonia
4. Neonatal conjunctivitis
What disease is caused by Chlamydia Trachomatis serotypes L1-L3
Lymphogranuloma venereum
1. acute lymphadenitis with a positive Frei test
2. ulcers
3. rectal strictures

Mnemonic: L1-3: Lymphogranuloma
Positive Frei test
Chlamydia Trachomatis serotypes L1-L3
Acquisition and treatment of neonatal conjunctivitis
Chlamydia trachomatis serotypes D-K acquired by passage through infected birth canal. Treat with erythromycin eye drops.
Characterization of spirochetes
Spiral-shaped bacteria with axial filaments
List of spirochetes
Mnemonic: BLT with spiral bacon

1. Borrelia (Big!)
2. Leptospira
3. Treponema
Visualization of Borrelia
Light microscopy with choice of aniline dye:
1. Wright's stain
2. Giemsa's stain
Stages of Lyme disease
1. Erythema chronicum migrans and flu-like symptoms
2. Neurologic and cardiac manifestations
3. Autoimmune migratory polyarthritis
Signs and symptoms of Lyme disease
Mnemonic: BAKE a Key Lime pie

1. Bell's palsy (and other CNS manifestations in Stage 2)
2. Arthritis (Autoimmune migratory in Stage 3)
3. Kardiac block (Stage 2)
4. Erythema chronicum migrans (Stage 1)
What species transmits Borrelia burgdorferi to humans?
Ixodes tick. Live o
Classic symptom of Lyme disease and which stage is it in?
Erythema chronicum migrans, an expanding "bull's eye" red rash with central clearing. Stage 1.
Animal reservoirs for borrelia burgdorferi
White-footed mouse and other small rodens, and the white-tailed deer. Ixodes tick picks up bugs from these animals and transmits them.
Most common setting for Borrelia burgdorferi infection
In the summer months in northeastern US (Lyme, CT)
What disease states does Treponema cause?
Treponema Pallidum causes syphilis.

Treponema Pertenue causes yaws (a non-STD tropical infection with positive VDRL)
What is yaws?
Treponema Pertenue causes yaws (a non-STD tropical infection with positive VDRL)
Presentation of primary syphilis
Painless chancre (localized disease)
What stage of syphilis: Painless chancre (localized disease)
Primary
Presentation of secondary syphilis
Disseminated disease with:
1. constitutional symptoms (fever, lymphadenopathy)
2. maculopapular rash (palms and soles)
3. condylomata lata

Mnemonic: Secondary means Systemic
What stage of syphilis: Disseminated disease with constitutional symptoms
Secondary syphilis
Presentation of tertiary syphilis
1. Gummas
2. Aortitis
3. Neurosyphilis (tabes dorsalis, general paresis)
4. Argyll Robertson pupil
What stage of syphilis: Gummas
tertiary syphilis
What stage of syphilis: Aortitis
tertiary syphilis
What stage of syphilis: Neurosyphilis (tabes dorsalis)
tertiary syphilis
What stage of syphilis: Argyll Robertson pupil
tertiary syphilis
What stage of syphilis: maculopapular rash (palms and soles)
Secondary syphilis
What stage of syphilis: condylomata lata
Secondary syphilis
Presentation of Congenital syphilis
1. Saber shins
2. Saddle nose
3. Deafness
What stage of syphilis: Saber shins
Congenital syphilis (not a stage)
What stage of syphilis: Saddle nose
Congenital syphilis (not a stage)
What stage of syphilis: Deafness
Congenital syphilis (not a stage)
Treatment for Syphilis
Penicillin G
Signs and symptoms of tertiary syphilis
1. Broad-based ataxia
2. Positive Romberg sign
3. Charcot joints
4. Stroke without hypertension
What is an Argyll-Robertson pupil?
Same as prostitute's pupil. Constricts with accommodation but is not reactive to light. Pathognomonic for tertiary syphilis.
What is the prostitute's pupil.
Same as Argyll-Robertson pupil. Constricts with accommodation but is not reactive to light. Pathognomonic for tertiary syphilis.
What is FTA-ABS used for?
FTA-ABS: Find the Antibody-Absolutely
1. Most specific for treponemes
2. Positive the earliest
3. Remains positive the longest
Interpret: Positive VDRL, Positive FTA
Active treponemal infection
Interpret: Positive VDRL, Negative FTA
Probably false positive

VDRL
1. Viruses (mono, hepatitis)
2. Drugs
3. Rheumatic fever and rheumatoid arthritis
4. Lupus and leprosy
Interpret: Negative VDRL, Positive FTA
Successfully treated treponemal infection
Sexuality of fungal spores
Asexual (mostly)
Which fungal infections are transmitted by inhalation of asexual spores?
1. Coccidioidomycosis
2. Histoplasmosis
What are conidia?
Asexual fungal spores
What disease states does Candida albicans cause?
1. Thrush esophagitis in immunocompromised patients (neonates, steroids, diabetes, AIDS)
2. endocarditis in IV drug users
3. vaginitis post-antibiotic use
4. diaper rash
5. Disseminated candidiasis to any organ
6. Chronic mucocutaneous candidiasis
Treatment for Candida Albicans infection
Superficial: Nystatin

Serious systemic: Amphotericin B
Histologic appearance of Candida Albicans
Budding yeast with pseudohyphae in culture at 20 degrees celsius

Germ tube formation at 37 degrees celsius
Candida albicans: Germ tube formation at 37 degrees celsius
What is this?
Candida albicans: Budding yeast with pseudohyphae in culture at 20 degrees celsius
What is this?
Which fungus causes thrush in immunocompromised
Candida albicans
Which fungus causes vulvovaginitis?
Candida albicans (high pH, diabetes, use of antibiotics)
Which fungus is endemic to Southwestern US?
Coccidioidomycosis
Which fungus is endemic to Mississippi and Ohio river valleys
Histoplasmosis
What fungus is this area known for: Southern Ohio
Histoplasmosis
What fungus is this area known for: Southern Illinois
Histoplasmosis
What fungus is this area known for: Missouri
Histoplasmosis
What fungus is this area known for: Kentucky
Histoplasmosis
What fungus is this area known for: Tennessee
Histoplasmosis
What fungus is this area known for: Arkansas
Histoplasmosis
What fungus is this area known for: Southern California
Coccidiomycosis
What fungus is this area known for: Southern Arizona
Coccidiomycosis
What fungus is this area known for: Mississippi river valley
Histoplasmosis (also Blastomycosis)
What fungus is this area known for: Ohio river valley
Histoplasmosis (also Blastomycosis)
What fungus is this area known for: Southwestern US
Coccidiomycosis
What fungus is this area known for: Rural Latin America
Paracoccidioidomycosis
What fungus is this area known for: Wisconsin
Blastomycosis
What fungus is this area known for: Minnesota
Blastomycosis
Spherule filled with endospores in coccidioidomycosis
What is this?
Characterize histoplasmosis histologically
Tiny yeast inside macrophages. Thin cell wall with no true capsule.
What is the vector for histoplasmosis?
Bird or bat droppings
What do bird and bat droppings carry?
Histoplasmosis
histoplasmosis showing intracellular organisms in bone marrow macrophages
What is this?
Paracoccidioidomycosis (captain's wheel appearance)
What is this?
Blastomycosis (Big, Broad-Based Budding)
What is this?
What characterizes dimorphic fungi?
Mold in soil (lower temperature) and yeast in tissue (body temperature)

Mnemonic: Cold is mold, heat is yeast
List the dimorphic fungi
Histoplasmosis, Blastomycosis, and Paracoccidioidomycosis (but not coccidioidomycosis which is a spherule in tissue)
Treatment for coccidiomycosis
Local: Fluconazole or ketoconazole

Systemic: Amphotericin B
Treatment for paracoccidiomycosis
Local: Fluconazole or ketoconazole

Systemic: Amphotericin B
Treatment for Histoplasmosis
Local: Fluconazole or ketoconazole

Systemic: Amphotericin B
Treatment for Blastomycosis
Local: Fluconazole or ketoconazole

Systemic: Amphotericin B
What is cultured on Sabouraud's agar?
Fungi (specifically dimorphic fungi)
What disease state does Malassezia furfur cause?
Tinea versicolor: Hypopigmented skin lesions which occur in hot humid weather.
Treatment for Tinea versicolor
Topical miconazole or selenium sulfide (Selsun)
What resembles spaghetti and meatballs histologically?
combination of mycelium strands and numerous spores of Malassezia furfur in KOH prep
What disease state does Cladosporium werneckii cause?
Tinea nigra: Infection of keratinized layer of skin. Appears as brownish spot.
What causes Tinea versicolor?
Malassezia furfur
What causes Tinea nigra?
Cladosporium werneckii
Treatment for Tinea nigra
topical salicylic acid
What are the common dermatophytes and what do they cause?
Microsporum, Trichophyton, and Epidermophyton

cause all the tineas except for versicolor and nigra
What causes Tinea corporis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
What causes Tinea cruris?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
What causes Tinea pedis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
What causes Tinea capitis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
What causes Tinea unguium?
AKA Tinea onychomycosis.

Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
What causes Tinea onychomycosis?
AKA Tinea unguium.

Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
How does Tinea corporis present?
Ring shape with a red raised border
How does Tinea cruris present?
AKA jock itch

Itchy red patches on groin and scrotum
How does Tinea capitis present?
Scaling on the scalp
How does Tinea unguium/onychomycosis present?
Nails are thickened discolored and brittle
Lab diagnosis of dermatophyte infection
1. Dissolve skin scrapings in KOH, which digests the keratin. Microscopic examination reveals branched hyphae.

2. Direct examination of skin with Wood's light (UV light at 365 nm wavelength) will fuoresce green if Microsporum.
Treatment for dermatophyte infection
1. Topical imidazoles
2. Oral griseofulvin (Tinea capitus and tinea unguium)
What causes a fungus ball?
Aspergillus
What disease states does Aspergillus cause?
1. Allergic bronchopulmonary aspergillosis
2. Lung cavity aspergilloma
3. Invasive aspergillosis
Histologic appearance of aspergillus
Mold (not dimorphic) with septate hyphae that branch at a V-shaped (45 degree) angle). Rare fruiting bodies.
Aspergillus (septate hyphae branching at 45 degrees with fruiting bodies)
What is this?
What disease states does cryptococcus neoformans cause?
1. Cryptococcal meningitis
2. Cryptococcosis
Histologic appearance of cryptococcus neoformans
5-10 micrometer yeasts with wide capsular halo. Narrow based unequal budding.
How is cryptococcus neoformans stained?
1. India ink
2. Latex agglutination test for polysaccharide capsular antigen
Where is cryptococcus neoformans found?
Soil and pigeon droppings.
What is the histologic appearance of Mucor?
Just like Rhizopus

Mold with irregular, broad, empty looking, nonseptate hyphae branching at wide angles (over 90 degrees)
What is the histologic appearance of Rhizopus?
Just like Mucor

Mold with irregular, broad, empty looking, nonseptate hyphae branching at wide angles (over 90 degrees)
Which patients are likely to have Mucor/Rhizopus?
1. Ketoacidotic diabetics
2. Leukemics
Where in the body does Mucor/Rhizopus proliferate?
1. Walls of blood vessels, causing infarction of distal tissue
2. Rhinocerebral frontal lobe abscesses
What is pneumocystis jirovecii?
Formerly pneumocystis carinii. Yeast (originally classified as a protozoan)
What disease states does Pneumocystis cause?
Most infection sasymptomatic. Immunosuppresion predisposes to disease.
How is pneumocystis diagnosed?
Lung biopsy or lavage. Methenamine silver stain of lung tissue.
Treatment for pneumocystis
Combination of TMP-SMX, Pentamidine, and Dapsone.
Characterization of sporotrix schenckii
Dimorphic fungus that lives on vegetation.
Presentation of sporotrichosis
1. Traumatically introduced into the skin by a thorn
2. Local pustule/ulcer with nodules along draining lymphatics (ascending lymphangitis)
3. Little systemic illness
What is rose gardener's disease?
Sporotrichosis
Histologic appearance of sporotrix schenckii
Cigar-shaped yeast visible in pus with unequal budding
Treatment for sporotrichosis
Itraconazole or potassium iodide
What disease states does Entamoeba histolytica cause?
1. Amebiasis
2. Bloody diarrhea (dysentery)
3. liver abscess
4. RUQ pain
What disease states does Giardia lamblia cause?
1. Giardiasis
2. Bloating
3. Flatulence
4. Foul-smelling diarrhea
What diseases are found in campers and hikers?
Yersinia pestis and Giardia lamblia
What disease states does Cryptosporidium cause?
Diarrhea

1. AIDS: Severe
2. Non-HIV: Mild watery
What disease states does Toxoplasma cause?
1. HIV: Brain abscess
2. Birth defects (ring-enhancing brain lesions)
What disease states does Plasmodium cause?
Malaria:
1. Cyclic fever
2. Headache
3. Anemia
4. Splenomegaly
5. Severe cerebral malaria (with Plasmodium falciparum)
What disease states does Trichomonas cause?
Trichomonas vaginalis causes vaginitis with foul-smelling greenish discharge, strawberry-colored mucosa, and itching and burning. Motile on wet prep.
What disease states does Trypanosoma cruzi cause?
Chagas' disease:
1. Dilated cardiomyopathy
2. Megacolon
3. Megaesophagus
What disease states does Trypanosoma gambiense cause?
African sleeping sickness
What disease states does Trypanosoma rhodesiense cause?
African sleeping sickness
What disease states does Leishmania donovani cause?
Visceral leishmaniasis (kala-azar or black fever):
fever, weight loss, anaemia and substantial swelling of the liver and spleen
What disease states does Naegleria cause?
Rapidly fatal meningoencephalitis
What disease states does Babesia cause?
Babesiosis: Fever and anemia
Which protozoa are transmitted by cysts?
1. Entamoeba histolytica
2. Giardia lamblia
3. Cryptosporidium
4. Toxoplasma

All water cysts except Toxo (cysts in meat or cat feces)
Which protozoa are transmitted by insect?
1. Plasmodium (Anophales mosquitoes)
2. Trypanosoma cruzi (Reduviid bug)
3. Other trypanosomas (Tsetse fly)
4. Leishmania (Sandfly)
5. Babesia (Ixodes tick)
Which protozoa are transmitted by swimming in freshwater lakes?
Naeglaria (via cribriform plate)
Which protozoa are transmitted sexually?
Trichomonas vaginalis
Which protozoa are transmitted by mosquito?
Plasmodium
Which protozoa are transmitted by reduviid bug?
Trypanosoma cruzi (the enses are transmitted by the tsetses, cruzii by reduviid))
Which protozoa are transmitted by tsetse fly?
Trypanosoma gambiense and rhodesiense (the enses are transmitted by the tsetses, cruzii by reduviid))
Which protozoa are transmitted by sandfly?
Leishmania
Which protozoa are transmitted by ixodes tick?
Babesia
How do you diagnose: Giardia lamblia
Trophozoites or cysts in stool (classic pair shaped organism with double nuclei like owl eyes)
How do you diagnose: Entamoeba histolytica
1. Trophozoites or cysts in stool

AND/OR

2. Serology
How do you diagnose: Cryptosporidium
Cysts on acid-fast stain
How do you diagnose: Toxoplasma
Serology, biopsy
How do you diagnose: Plasmodium
Blood smear
How do you diagnose: Trypanosoma
Blood smear
How do you diagnose: Babesia
Blood smear, no RBC pigment, appears as "maltese cross"
How do you diagnose: Leishmania
Macrophages containing amastigotes
How do you diagnose: Naegleria
Amebas in spinal fluid
Treatment for: Entameba histolytica
Metronidazole and iodoquinol
Treatment for: Giardia lamblia
Metronidazole
Treatment for: Trichomonas vaginalis
Metronidazole
Treatment for: Cryptosporidium
None
Treatment for: Naegleria
None
Treatment for: Plasmodium
1. Choloroquine
2. additonal Primaquine (for P. vivax and P. ovale to prevent relapse or liver damage)
3. sulfadoxine plus pyrimethamine
4. Mefloquine
5. Quinine
Treatment for: Trypanosoma cruzi
Nifurtimox
Treatment for: Trypanosoma gambiense and rhodesiense
If blood-borne, suramin.

If CNS penetration, melarsoprol.
Treatment for: Leishmania
Sodium stibogluconate
Treatment for: Babesia
Qunine, clindamycin
Treatment for: Toxoplasma
Sulfadiazine plus pyrimethamine
Type of bug: Candida albicans
Dimorphic fungus, cutaneous OR systemic infection
Type of bug: Coccidioides immitis
Monomorphic fungus, systemic infection
Type of bug: Histoplasma capsulatum
Dimorphic fungus, systemic infection
Type of bug: Blastomyces dermatidis
Dimorphic fungus, systemic infection
Type of bug: Paracoccidioides brasiliensis
Dimorphic fungus, systemic infection
Type of bug: Malassezia furfur
Monomorphic fungus, superficial infection
Type of bug: Cladosporium werneckii
Monomorphic fungus, superficial infection
Type of bug: Microsporum
Monomorphic fungus, cutaneous infection
Type of bug: Trichophyton
Monomorphic fungus, cutaneous infection
Type of bug: Epidermophyton
Monomorphic fungus, cutaneous infection
Type of bug: Aspergillus fumigatus
Monomorphic fungus, opportunistic systemic infection
Type of bug: Cryptococcus neoformans
Monomorphic fungus, opportunistic systemic infection
Type of bug: Mucor
Monomorphic fungus, opportunistic systemic infection
Type of bug: Rhizopus
Monomorphic fungus, opportunistic systemic infection
Type of bug: Pneumocystis jirovecii
Monomorphic fungus, opportunistic systemic infection
Type of bug: Sporothrix schenckii
Dimorphic fungus, subcutaneous infection with some lymphatic spread
Type of bug: Entamoeba histolytica
Protozoan
Type of bug: Giardia lamblia
Protozoan
Type of bug: Naegleria
Protozoan
Type of bug: Plasmodium
Protozoan
Type of bug: Cryptosporidium
Protozoan
Type of bug: Toxoplasma
Protozoan
Type of bug: Trichomonas
Protozoan
Type of bug: Trypanosoma
Protozoan
Type of bug: Leishmania
Protozoan
Type of bug: Babesia
Protozoan
Type of bug: Taenia solium
Helminth: Cestode (Tapeworm)
Type of bug: Echinococcus granulosus
Helminth: Cestode (Tapeworm)
Type of bug: Schistosoma
Helminth: Trematode (fluke)
Type of bug: Clonorchis sinensis
Helminth: Trematode (fluke)
Type of bug: Paragonimus westermani
Helminth: Trematode (fluke)
Type of bug: Ancylostoma duodenale
Helminth: Nematode (roundworm)
Type of bug: Ascaris lumbricoides
Helminth: Nematode (roundworm)
Type of bug: Enterobius vermicularis
Helminth: Nematode (roundworm)
Type of bug: Strongyloides stercolaris
Helminth: Nematode (roundworm)
Type of bug: Trichinella spiralis
Helminth: Nematode (roundworm)
Type of bug: Dracunculus medinensis
Helminth: Nematode (roundworm)
Type of bug: Loa loa
Helminth: Nematode (roundworm)
Type of bug: Onchocera volvulus
Helminth: Nematode (roundworm)
Type of bug: Toxocara canis
Helminth: Nematode (roundworm)
Type of bug: Wuchereria bancrofti
Helminth: Nematode (roundworm)
Type of bug: Treponema
Spirochete
Which worm: Undercooked pork
1. Taenia solium (tapeworm)
2. Trichinella spiralis (roundworm)
Which worm: Brain cysts
Taenia solium (tapeworm)
Which worm: Liver cysts
Echniococcus granulosus (tapeworm)
Important points about echinococcus granulosus
Tapeworm (Cestode)
1. Ingested eggs from dog feces
2. Liver cysts
3. Cysts release antigens and cause anaphylaxis
Taenia solium: Treatment
Praziquantel/niclosamide. Albendazole for cysticercosis
Echinococcus granulosus: Treatment
Albendazole
Characterization of Schistosoma
Fluke (Trematode)
1. Hosted by snails
2. Penetrate skin of humans
Presentation of Schistosoma
Spleen and liver:
1. Granulomas
2. Fibrosis
3. Inflammation
Schistosoma: Treatment
Praziquantel
Which worm: Portal hypertension
Schistosoma mansoni
Which worm: Hematuria
Schistosoma haematobium
Which worm: Bladder cancer
Schistosoma haematobium
Important points about Clonorchis sinensis
Fluke (trematode)
1. Undercooked fish
2. Inflammation of biliary tract
Which worm: Undercooked fish
Clonorchis sinensis
Clonorchis sinensis: Treatment
Praziquantel
Which worm: B12 deficiency
Diphyllobothrium latum (tapeworm)
Which worm: Undercooked crab meat
Paragonimus westermani (fluke)
Important points about Pargonimus westermani
Trematode (fluke)
1. Undercooked crabmeat
2. Inflammation and secondary bacterial infection of the lung
3. Hemoptysis
Which worm: Hemoptysis
Paragonimus westermani (fluke)
Paragonimus westermani: Treatment
Praziquantel
Which worm: Microcytic anemia
Ancylostoma (aka hookworm) and Necator (both roundworms)
Which worm: Perianal pruritus
Enterobius vermicularis (aka pinworm, a roundworm)
Important points about Ancylostoma duodenale
Nematode (roundworm)
1. Aka hookworm
2. Larvae penetrate skin of feet
3. Intestinal infection can cause anemia
Ancylostoma duodenale: Treatment
Mebendazole/pyrantel pamoate
Important points about Ascaris lumbricoides
Nematode (roundworm)
1. Aka giant roundworm (Up to 1 foot in length!)
2. Eggs are visible in feces.
3. Intestinal infection
Ascaris lumbricoides: Treatment
Mebendazole/pyrantel pamoate
Important points about Enterobius vermicularis
Nematode (roundworm)
1. Aka pinworm
2. Food contaminated with eggs
3. Intestinal infection
4. Anal pruritus (scotch tape test)
Enterobius vermicularis: Treatment
Mebendazole/pyrantel pamoate
Important points about Strongyloides stercoralis
Nematode (roundworm)
1. Larvae in soil penetrate the skin
2. Intestinal infection
Strongyloides stercoralis: treatment
Ivermectin/thiabendazole
Important points about Trichinella spiralis
Roundworm (nematode)
1. Undercooked meat, usually pork
2. Inflammation of muscle
3. Periorbital edema
Trichinella spiralis: Treatment
Thiabendazole
Important points about Dracunculus medinensis
Nematode (roundworm)
1. In drinking water
2. Skin inflammation and ulceration
Dracunculus medinensis: Treatment
Niridazole
Important points about Loa loa
Nematode (roundworm)
1. Transmitted by deer fly
2. Causes swelling in skin
3. Can see worm crawling in conjunctiva
Loa loa: Treatment
Diethylcarbamazine
Important points about Onchocerca volvulus
Nematode (roundworm)
1. Transmitted by female blackflies
2. Causes river blindness
Onchocerca volvulus: Treatment
Ivermectin
Important points about Toxocara canis
Nematode (roundworm)
1. Food contaminated with eggs
2. Causes granulomas (if in retina, blindness)
3. Visceral larva migrans
Toxocara canis: Treatment
Diethylcarbamazine
Important points about Wuchereria bancrofti
Nematode (roundworm)
1. Female mosquito
2. Causes blockage of lymphatic vessels (elephantiasis)
Wuchereria bancrofti: Treatment
Diethylcarbamazine
Which DNA viruses are double stranded?
All DNA viruses except for Parvoviridae

Mnemonic: All are dsDNA like ours, except "Part-of-a-virus" which is ss.
Which DNA viruses are single stranded?
Parvoviridae
Which DNA viruses have linear genomes?
All except papova virus and hepadna which are circular
Which DNA viruses have circular genomes?
papova virus and hepadna which are circular
Which RNA viruses are single stranded?
All except Reovirus (ds)

Mnemonic: All are ssRNA like ours, except "RepatO-virus" which is ds.
Which RNA viruses are double stranded?
Reovirus (ds)

Mnemonic: All are ssRNA like ours, except "RepatO-virus" which is ds.
Which DNA viruses have infectious naked nucleic acids?
Most dsDNA (except poxvirus and HBV)
Which DNA viruses have non-infectious naked nucleic acids?
poxvirus and HBV
Which RNA viruses have infectious naked nucleic acids?
+ strand ssRNA (almost the same as mRNA)
Which RNA viruses have noninfectious naked nucleic acids?
- strand ssRNA

Mnemonic: Always Bring Polymerase Or Fail Replication
1. Arena
2. Bunya
3. Paramyxo
4. Orthomyxo
5. Filo
6. Rhabdo
Which enveloped viruses acquire their envelopes from the plasma membrane?
All except herpesviruses (nuclear membrane)
Which enveloped viruses acquire their envelopes from the nuclear membrane?
Only herpesviruses
Which viruses are haploid?
All except retroviruses (diploid)
Which viruses are diploid?
Retroviruses
Where do DNA viruses replicate?
In the nucleus (except pox)
Where do RNA viruses replicate?
Cytoplasm (except influenza and retroviruses)
DNA virus families
Mnemonic: DNA viruses are HHAPPPy

1. Hepadna
2. Herpesviruses
3. Adenovirus
4. Parvovirus
5. Papovavirus
6. Poxvirus
Which DNA viruses are icosahedral?
All except pox (complex)
Which DNA viruses replicate in the nucleus?
All except pox (carries own DNA-dependent RNA polymerases)
Which DNA viruses are naked?
Mnem: Get naked for your PAP
1. Parvo
2. Adeno
3. Papova
Which DNA viruses are enveloped?
HPH
1. Hepadna
2. Pox
3. Herpes
Humoral or Cell-mediated immunity: Live attenuated vaccines
Both (with a few cases of reversion to virulence)
Humoral or Cell-mediated immunity: Killed vaccines
Humoral immunity (stable)
Live/Killed and Egg-based/Recombinant: MMR vaccine
Live attenuated, egg-based

Mnemonic: FRY an egg (Flu, mmR, Yellow fever)
Live/Killed and Egg-based/Recombinant: Sabin polio vaccine
Live attenuated
Live/Killed and Egg-based/Recombinant: VZV vaccine
Live attenuated
Live/Killed and Egg-based/Recombinant: Yellow fever vaccine
Live attenuated, egg-based

Mnemonic: FRY an egg (Flu, mmR, Yellow fever)
Live/Killed and Egg-based/Recombinant: Smallpox vaccine
Live attenuated
Live/Killed and Egg-based/Recombinant: Adenovirus vaccine
Live attenuated
Live/Killed and Egg-based/Recombinant: Rabies vaccine
Killed

Mnemonic: RIP Always (Rabies, Influenza, salk Polio, hAv)
Live/Killed and Egg-based/Recombinant: Influenza vaccine
Killed, egg-based

Mnemonic: FRY an egg (Flu, mmR, Yellow fever)

Mnemonic: RIP Always (Rabies, Influenza, salk Polio, hAv)
Live/Killed and Egg-based/Recombinant: Salk polio vaccine
Killed

Mnemonic: RIP Always (Rabies, Influenza, salk Polio, hAv)
Live/Killed and Egg-based/Recombinant: HAV vaccine
Killed

Mnemonic: RIP Always (Rabies, Influenza, salk Polio, hAv)
Live/Killed and Egg-based/Recombinant: HBV vaccine
Recombinant (antigen is recombinant HBsAg)
Definition: Viral recombination
Exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology
What is this viral process: Exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology
Viral recombination
Definition: Viral Reassortment
Viruses with segmented genomes exchange segments. Same as high frequency recombination. Cause of worldwide pandemics.
What is this viral process: Viruses with segmented genomes exchange segments.
Viral Reassortment

Same as high frequency recombination. Cause of worldwide pandemics.
Definition: Viral Complementation
When 1 of 2 viruses that infect the cell has a mutation that results in nonfunctional protein and the non-mutated virus "complements" the mutated one by making a functional protein that serves both viruses.
What is this viral process: When 1 of 2 viruses that infect the cell has a mutation that results in nonfunctional protein and the non-mutated virus makes a functional protein that serves both viruses.
Viral Complementation
Definition: Viral Phenotypic Mixing
Genome of virus A can be coated with the surface proteins of virus B. Type B protein coat determines the infectivity of the phenotypically mixed virus. Progeny of type A however have type A coat from type A genes.
What is this viral process: Genome of virus A can be coated with the surface proteins of virus B. Type B protein coat determines the infectivity of the phenotypically mixed virus.
Viral Phenotypic Mixing

Progeny of type A however have type A coat from type A genes.
What does it mean for a virus to be naked?
It has only a nucleocapsid, and no envelope.
Which RNA viruses are enveloped?
1. Measles
2. Mumps
3. Rubella
4. RSV
5. Rabies
6. HTLV
7. HIV
8. Influenza
9. Parainfluenza

Mnem: MMRRHHflu
Which RNA viruses are naked?
Mnemonic: Naked CPR

1. Calicivirus
2. Picornavirus [Enteroviruses (polio, coxsackie, echo, HAV), Rhino]
3. Reovirus
What does it mean for viruses to be negative stranded?
Must transcribe negative strand to positive, using RNA polymerase.
Negative stranded viruses
Mnem: Always Bring Polymerase or Fail Replication

1. Arenaviruses
2. Bunyaviruses
3. Paramyxoviruses
4. Orthomyxoviruses
5. Filoviruses
6. Rhabdoviruses
Segmented viruses
Mnem: BOAR

1. Bunyaviruses
2. Orthomyxoviruses (flu)
3. Arenaviruses
4. Reovirus
How many segments in influenza?
8
Which RNA viruses are linear?
All except the BAD seeds (Bunyavirus, Arenavirus, Deltavirus)
Which RNA viruses are circular?
the BAD seeds
1. Bunya
2. Arena
3. Delta
Which RNA viruses are icosahedral?
Naked (CPR) FaRT
1.Calici
2.Picorna
3.Reo
4.Flavi
5.Retro
6.Toga
Which RNA viruses are helical?
Mnemonic: The COP BARFeD up a helix.

1. Corona
2. Orthomyxo
3. Paramyxo
4. Bunya
5. Arena
6. Rhabdo
7. Filo
8. Delta
Which viruses have reverse transcriptase?
Retro and HBV
Medical importance of HSV-1
1. Oral (and some genital) lesions (Gingivostomatitis)
2. Keratoconjunctivitis
3. Temporal lobe encephalitis
Medical importance of HSV-2
Genital (and some oral) lesions
Medical importance of VZV
1. Chickenpox
2. Shingles
3. Encephalitis
4. Pneumonia
Medical importance of EBV
1. Mononucleosis
2. Burkitt's lymphoma
Medical importance of CMV
1. Infection in immunosuppressed (especially transplant)
2. Congenital defects
3. Mononucleosis (negativie Monospot)
4. Pneumonia
Medical importance of HHV-6
Roseola (exanthem subitum):
1. High fever lasting 3 to 5 days which resolves and is followed by a...
2. Rash: mostly on trunk, lasting a day or two
Medical importance of HHV-8
Kaposi's sarcoma-associated herpesvirus
List of important Herpesviruses
HSV 1 and 2, VZV, EBV, CMV, HHV 6 and 8
Medical importance of Adenovirus
1. Febrile pharyngitis (sore throat)
2. Pneumonia
3. Conjunctivitis (pink eye)
Medical importance of Parvovirus
B19 virus causes:
1. Aplastic crises in sickle cell disease
2. "slapped cheeks" rash---erythema infectiosum (fifth disease)
3. Hydrops fetalis
List of Papova viruses
1. PApilloma
2. POlyoma (human BK and JC)
3. Simian VAcuolating virus (does not affect humans)
Medical importance of Papilloma virus
causes warts and cervical cancer, including CIN (cervical intraepithelial neoplasia)
Medical importance of JC virus
Progressive multifocal leukoencephalopathy in HIV
List of Pox viruses
1. Smallpox
2. Vaccinia (cowpox "milkmaid's blisters")
3. Molluscum contagiosum
List of Picornaviruses
Mnemonic: PERCH on a "peak"

1. Poliovirus
2. Echovirus
3. Rhinovirus
4. Coxsackievirus
5. HAV
Medical importance of Poliovirus
Fecal-oral transmission
What is IPV?
Inactivated polio vaccine (Salk)
What is OPV?
Oral Polio vaccine (Sabin)
Medical importance of Echovirus
Aseptic meningitis
Medical importance of Rhinovirus
"common cold"
Medical importance of Coxsackie virus
1. Aseptic meningitis
2. herpangina-febrile pharyngitis
3. hand, foot, and mouth disease
4. myocarditis
List of Caliciviruses
HEV, Norwalk virus
Medical importance of Norwalk virus
viral gastroenteritis
List of Reoviruses
Reovirus, Rotavirus
Medical importance of Reovirus sp.
Colorado tick fever
Medical importance of Rotavirus
#1 cause of fatal diarrhea in children
Medical importance of Flavivirus
1. HCV
2. Yellow fever
3. Dengue
4. St. Louis encephalitis
5. West Nile virus
List of Arboviruses
Arboviruses are ARthropod BOrne viruses
1. Togaviridae
2. Flaviviridae
3. Bunyaviridae
Medical importance of Togaviruses
1. Rubella (German measles)
2. Eastern equine encephalitis
3. Western equine encephalitis
List of Retroviruses
1. HIV
2. HTLV
Medical importance of Coronavirus
1. common cold
2. SARS
Medical importance of Orthomyxovirus
Influenza
List of Paramyxoviruses
PaRaMyxovirus
1. Parainfluenza
2. RSV
3. Measles
4. Mumps
Medical importance of Parainfluenza
croup
Medical importance of RSV
Bronchiolitis in babies. Treat with Ribavirin.
Medical importance of Rhabdoviruses
Rabies
Medical importance of Filoviruses
Ebola or Marburg hemorrhagic fever, both are often fatal
Medical importance of Arenaviruses
1. LCV (lymphocytic choriomeningitis)
2. Meningitis (spread by mice)
Medical importance of LCV
lymphocytic choriomeningitis
Medical importance of Hantavirus
hemorrhagic fever, pneumonia
Medical importance of Bunyaviruses
1. California encephalitis
2. Sandfly/Rift Valley fevers
3. Crimean-Congo hemorrhagic fever
4. Hantavirus
Characterize Picornaviruses
1. 1 large polypeptide that is cleaved by proteases into functional viral proteins
2. All except Rhino and HAV can cause aseptic meningitis
How many serotypes of Rhinovirus?
100
Mechanism of rotavirus diarrhea
Villous destruction with atrophy leads to decreased absorption of Na and water
How many serotypes of Paramyxovirus?
all viruses have 1 except parainfluenza which has 4
Signs and symptoms of mumps
Mnemonic: Mumps make your parotid glands and testes as big as POM-poms

1. Parotitis
2. Orchitis (inflammation of testes, can cause sterility especially after puberty)
3. Meningitis
Signs and symptoms of measles
1. Koplik spots (bluish-gray spots on buccal mucosa) diagnostic
2. Subacute sclerosing panencephalitis (child, many years after measles infection, slowly progressing)
3. Encephalitis
4. Giant cell pneumonia (in immunosuppressed)
5. 3 Cs: (Cough, coryza, conjunctivitis)
6. Head to toe rash lasting 6 days (slowly dripping bucket of paint)
Antigens in influenza virus
Hemaglutinin and Neuraminidase
Difference between genetic drift and shift
Drift: Minor changes based on random mutation

Shift: Reassortment of viral genome (such as when flu A virus recombines with swine flu A virus)

Sudden Shift is more deadly than graDual Drift
Treatment for influenza
A only: Amantadine and rimantadine

A and B: Zanamivir and Oseltamivir (neuraminidase inhibitors) for both influenza A and B
What are negri bodies?
Characteristic cytoplasmic inclusions in neurons infected by rabies virus.
What shape is the rabies capsid?
Bullet shaped.
Mechanism of rabies disease
1. Animal bite
2. Virus travels to CNS in retrograde fashion up nerve axons
3. Incubates for weeks to 3 months
What does rabies cause?
Fatal enchephalitis with seizures and hydrophobia
How is rabies acquired?
US: Skunk, raccoon and bat bites

Abroad: Dog bites
What is dengue fever?
break-bone fever, caused by flaviviruses. A variant in Southeast Asia is hemorrhagic shock syndrome.
How is yellow fever transmitted?
Arbovirus, by Aedes mosquitos, from monkey or human reservoir
Signs and symptoms of yellow fever
1. High fever
2. Black vomitus
3. Jaundice
4. Councilman bodies in liver (nonspecific)
How is HSV-1 transmitted?
Respiratory secretions and saliva
How is HSV-2 transmitted?
Sexual contact and perinatally
How is VZV transmitted?
Respiratory secretions
How is EBV transmitted?
Respiratory secretions, saliva
How is CMV transmitted?
1. Congenital
2. Transfusion
3. Sexual contact
4. Saliva
5. Urine
6. Transplant
How is HHV-8 transmitted?
Sexual contact
Treatment for CMV
Ganciclovir or Foscarnet
What kind of cell does Epstein Barr virus infect?
B cells
How does mononucleosis present?
1. Fever
2. Hepatosplenomegaly
3. Pharyngitis
4. Lymphadenopathy (especially posterior auricular nodes)
Peak incidence of mononucleosis
15-20 years old (peak kissing years)
Laboratory diagnosis of mononucleosis
1. Monospot test: Heterophil antibodies detected by agglutination of sheep RBCs. In EBV, positive. In CMV, negative.
2. Abnormal circulating CD8 cells.
Tzanck test
Smear of opened skin vesicle to detect multinucleated giant cells. Used to assay for HSV-1, HSV-2, VZV

Mnem: Tzanck heavens I do not have herpes. (helps if you do it in an eastern european accent)
HAV: Virus family, nucleic acid type, envelope, incubation period, transmission, carriers
Virus family: ssRNA picornavirus
Envelope: no
Incubation period: Short (3 weeks)
Transmission: Fecal-oral
Carriers: No
HBV: Virus family, nucleic acid type, envelope, incubation period, transmission, carriers
Virus family: dsDNA hepadna virus
Envelope: yes
Incubation period: Long (3 months)
Transmission: Parenteral, sexual, in utero
Carriers: Yes
HCV: Virus family, nucleic acid type, envelope, incubation period, transmission, carriers
Virus family: ssRNA flavivirus
Envelope: yes
Incubation period: Variable (2 weeks to 5 months)
Transmission: Blood
Carriers: Yes
HDV: Virus family, nucleic acid type, envelope, incubation period, transmission, carriers
Virus family: ssRNA deltavirus
Envelope: yes
Incubation period: Variable (2 weeks to 2 months)
Transmission: Parenteral, sexual, in utero
Carriers: Yes
HEV: Virus family, nucleic acid type, envelope, incubation period, transmission, carriers
Virus family: ssRNA calicivirus
Envelope: no
Incubation period: Variable (2 weeks to 2 months)
Transmission: Fecal-oral
Carriers: No
Characterize Hepatitis A
1. Asymptomatic (usually)
2. Acute
3. Alone (no carriers; naked ssRNA)
Characterize Hepatitis B
Blood borne
Characterize Hepatitis C
1. Chronic
2. Cirrhosis
3. Carcinoma
4. Carriers
Characterize Hepatitis D
1. Defective
2. Dependent on HBV
Characterize Hepatitis E
1. Enteric
2. Expectant mothers (high mortality rate)
3. Epidemics
What does IgM HAVAb measure?
IgM antibody to HAV. Best test to detect active Hepatitis A.
What does HBsAg measure?
HBV surface antigen. Continued presence indicates carrier state.
What does HBsAb measure?
Antibody to HBsAg. Provides immunity to hepatitis B.
What does HBcAg measure?
Antigen associated with core of HBV, doesn't seem to be measured.
What does HBcAb measure?
Antibody to core antigen. Positive during window period (no HBsAg or HBsAb detected). IgM HBcAb is an indicator of recent disease.
What does HBeAg measure?
A second different antigenic determinant in the HBV core. Important indicator of transmissibility. (BEware!)
What does HBeAb measure?
Antibody to e antigen; indicates low transmissibility.
Characterize this patient:
HBsAg is positive;
HBsAb is negative;
HBcAb is positive;
Acute disease. (HBcAb is IgM in acute stage, and IgG in chronic or recovered stage.)
Characterize this patient:
HBsAg is negative;
HBsAb is negative;
HBcAb is positive;
Window phase, follows acute infection.
Characterize this patient:
HBsAg is negative;
HBsAb is positive;
HBcAb is positive;
Complete recovery.
Characterize this patient:
HBsAg is positive;
HBsAb is negative;
HBcAb is positive;
Chronic carrier. (Surface antibody is present, but bound to surface antigen.)
What is gag?
Gene that encodes for p24 capsid, the nucleocapsid in HIV
What is env?
Gene that encodes for gp41 and gp120 proteins, the envelope proteins in HIV.
What is p17?
Interior envelope protein in HIV
What is p24?
Nucleocapsid protein in HIV, coded for by gag gene.
What is gp41?
Envelope protein which traverses bilayer. If it is a mushroom stalk, then gp120 is the head. Both coded for by env.
What is gp120?
Envelope protein that serves as mushroom cap to gp41 stalk. Both coded for by env.
What is pol?
Gene which codes for HIV reverse transcriptase
HIV diagnostic tests
Presumptive diagnosis: ELISA (sensitive, high false-positive rate, and low threshhold)

Confirmation: Western blot assay (specific, high false-negative rate, and high threshold)

PCR viral load used to monitor drug therapy on viral load
Timeframe for HIV diagnosis
ELISA/Western blot often:

Falsely negative in first 1-2 months of HIV infection
Falsely positive initially in babies born to infected mothers (anti-gp120 crosses placenta)
AIDS diagnosis
One of the following:
1. less than 200 CD4 cells
2. HIV positive with AIDS indicator condition (eg pneumocystis infection)
3. CD4/CD8 ratio less than 1.5
CCR5 mutation: What does it mean?
HIV susceptibility.

Homozygous means immunity, heterozygous means slower course (long-term non production)
CXCR1 mutation
HIV susceptibility. Rapid progression to AIDS.
What is the likelihood of CCR5 mutation?
% of US caucasians
Homozygous: 1
Heterozygous: 20
Relative HIV-related levels aproximately 1.5 months after infection
In descending order:
1. CD4 lymphocytes (initial trough)
2. Virus p24 antigen (initial peak)
3. Anti-p24 Ab
4. Anti-gp120 Abs

Highest period of acute symptoms
Relative HIV-related levels aproximately 2 months after infection
In descending order:
1. CD4 lymphocytes (rise from initial trough back to near pre-infection levels before leveling out [the mark of end of acute symptoms])
2. Anti-p24 Ab (Reaching peak [not reached until approximately 3 years])
3. Anti-gp120 Abs (Reaching peak [not reached until approximately 3 years])
4. Virus p24 antigen (very low levels)
Relative HIV-related levels more than 3 years after infection: Early phase
In descending order:
1. CD4 lymphocytes (begins linear descent)
2. Anti-p24 Ab (descent begins at faster rate than CD4)
3. Anti-gp120 Abs (slow descent begins)
4. Virus p24 antigen (slow rise)
Relative HIV-related levels more than 3 years after infection: First middle phase
In descending order:
1. CD4 lymphocytes (continues linear descent)
2. Anti-gp120 Abs (slow descent continues)
3. Anti-p24 Ab (having dropped below Anti-gp120, descent continues at slower rate)
4. Virus p24 antigen (fast rise begins)
Relative HIV-related levels more than 3 years after infection: Second middle phase
In descending order:
1. CD4 lymphocytes (continues linear descent)
AND
1. Virus p24 antigen (already passed gp-120 Abs and about to pass CD4 lymphocytes)
3. Anti-gp120 Abs (slow descent continues)
3. Anti-p24 Ab (approximately 1/3 amount of p24 antigen, slow descent continues)
Relative HIV-related levels more than 3 years after infection: Third middle phase
In descending order:
1. Virus p24 antigen (already passed gp-120 Abs and about to pass CD4 lymphocytes)
2. CD4 lymphocytes (continues linear descent, about to drop below anti-g120 Abs)
3. Anti-gp120 Abs (slow descent continues)
4. Anti-p24 Ab (approximately 1/3 to 1/4 amount of p24 antigen, slow descent continues)
Relative HIV-related levels more than 3 years after infection: Late phase
In descending order:
1. Virus p24 antigen (leveled out at nearly 20x anti-p24 antibody)
2. Anti-gp120 Abs (little less than half p24 antigen)
3. Anti-p24 Ab (1/20 amount of p24 antigen)
AND
3. CD4 lymphocytes
Opportunistic infections and disease in AIDS attacking the brain
1. Cryptococcal meningitis
2. Toxoplasmosis
3. CMV encephalopathy
4. AIDS dementia
5. PML (JC virus)
Opportunistic infections and disease in AIDS attacking the eyes
CMV retinitis
Opportunistic infections and disease in AIDS attacking the mouth and throat
1. Thrush (Candida albicans)
2. HSV
3. CMV
4. Oral hairy leukoplakia (EBV)
Opportunistic infections and disease in AIDS attacking the lungs
1. Pneumocystis pneumonia (PCP)
2. TB
3. Histoplasmosis
Opportunistic infections and disease in AIDS attacking the GI tract
1. Cryptosporidiosis
2. Mycobacterium avium-intracellulare complex
3. CMV colitis
4. non-Hodgkin's lymphoma (EBV)
Opportunistic infections and disease in AIDS attacking the skin
1. Shingles (VZV)
2. Kaposi's sarcoma (HHV-8)
Opportunistic infections and disease in AIDS attacking the genitals
1. Genital herpes
2. Genital warts
3. Cervical cancer (HPV)
When does HIV encephalitis occur?
Late in the course of HIV infection
Mechanism of HIV encephalitis
Virus gains CNS access via infected macrophages
Pathologic presentation of HIV encephalitis
Microglial nodules with multinucleated giant cells
What are prions?
Infectious agents that do not contain RNA or DNA, only proteins, that are encoded by cellular genes.
Diseases caused by prions
1. Creutzfeldt-Jakob disease
2. Kuru
3. Scrapie (in sheep)
4. Mad cow disease (association with human spongiform encephalopathy)
5. Fatal familial insomnia
What is Creutzfeldt-Jakob disease
Prion caused disease with rapid progressive dementia
Mechanism of prion pathology
Normal proteins (alpha-helices) become pathologic (beta-pleated sheets)
Dominant normal flora of dental plaque
Streptococcus mutans
Dominant normal flora of the skin
Staphylococcus epidermidis
Dominant normal flora of the nose
Staphylococcus aureus
Dominant normal flora of the colon
1. Bacteroides fragilis
2. E. coli
Dominant normal flora of the vagina
1. Lactobacillus
2. E. coli
3. Group B strep
Dominant normal flora in neonates
When delivered by cesarean section, none, but are rapidly colonized after birth.
Most common causes of pneumonia in people 6 weeks to 18 years old.
1. Viruses (RSV)
2. Mycoplasma
3. Chlamydia pneumoniae
4. Streptococcus pneumoniae
Most common causes of pneumonia in people 18 to 40 years old.
1. Mycoplasma
2. Chlamydia pneumoniae
3. Streptococcus pneumoniae
Most common causes of pneumonia in people 40 to 65 years old.
1. Streptococcus pneumoniae
2. Haemophilus influenzae
3. Anaerobes
4. Viruses
5. Mycoplasma
Most common causes of pneumonia in people over 65 years old.
1. Streptococcus pneumoniae
2. Anaerobes
3. Viruses
4. Haemophilus influenzae
5. Gram negative rods
Most common causes of nosocomial pneumonia
1. Staphylococcus
2. Gram negative rods
Most common causes of immunocompromised pneumonia
1. Staphylococcus
2. Gram negative rods
3. Fungi
4. Viruses
5. Pneumocystis jirovecii (with HIV)
Most common causes of aspiration pneumonia
Anaerobes
Most common causes of pneumonia in alcoholics or IV drug users
1. Streptococcus pneumoniae
2. Klebsiella
3. Staphylococcus
Most common causes of postviral pneumonia
1. Staphylococcus
2. Haemophilus influenzae
Most common causes of neonatal pneumonia
1. Group B streptococci
2. E. coli
Most common causes of atypical pneumonia