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352 Cards in this Set

  • Front
  • Back
where is peptidoglycan found? what is its function?
- bacterial cell wall
- gives rigid support and protects against osmotic pressure
what is the major surface antigen in gram positive bacteria?
the cell wall
what portion of the gram positive cell wall induces TNF and IL-1?
teichoic acid
what is the major surface antigen in gram negative bacteria?
the outer membrane specifically lipopolysaccharide
what portion of the gram negative bacteria induces TNF and IL-1?
Lipid A portion of the lipopolysaccharide
what is the most toxic component of lipopolysaccharide?
Lipid A
what size ribosomes do bacteria have? how do they differ from human?
- 50s and 30s subunits
- humans have 40s and 60s subunits
a bacteria is resistant to beta-lactams. where is the most likely spot to find beta-lactamase?
the periplasm (the space between the outer membrane and the cytoplasmic membrane)
what is the role of a bacterial capsule? what is made out of? do all bacteria have them?
- to protect against phagocytosis
- polysaccharides
- no
what structure allows for bacterial sex?
pilus/fimbria
where is peptidoglycan found? what is its function?
- bacterial cell wall
- gives rigid support and protects against osmotic pressure
what is the major surface antigen in gram positive bacteria?
the cell wall
what portion of the gram positive cell wall induces TNF and IL-1?
teichoic acid
what is the major surface antigen in gram negative bacteria?
the outer membrane specifically lipopolysaccharide
what portion of the gram negative bacteria induces TNF and IL-1?
Lipid A portion of the lipopolysaccharide
what is the most toxic component of lipopolysaccharide?
Lipid A
what size ribosomes do bacteria have? how do they differ from human?
- 50s and 30s subunits
- humans have 40s and 60s subunits
a bacteria is resistant to beta-lactams. where is the most likely spot to find beta-lactamase?
the periplasm (the space between the outer membrane and the cytoplasmic membrane)
what is the role of a bacterial capsule? what is made out of? do all bacteria have them?
- to protect against phagocytosis
- polysaccharides
- no
what structure allows for bacterial sex?
pilus/fimbria
what is glycocalyx?
a polysaccharide that mediates bacterial adherence to surfaces
name the circular gram positive pathogens?
- staphylococcus
- streptococcus
name the rod shaped gram positive pathogens?
- clostridium
- corynebacterium
- bacillus
- listeria
name the branching filamentous gram positive bacteria?
- actinomyces
- nocardia
what bacteria stain with acid-fast stain (Ziehl-Neelsen)?
mycobacterium
what bacteria has no cell wall and does not stain?
mycoplasma
what bacteria are circular and gram negative?
neisseria
what bacteria are spiral and gram negative?
the spirochetes
- leptospira
- borrelia
- treponema
what bacteria uses the giemsa stain to be seen under light microscopy?
- borrelia
- chlamydiae
what bacteria are pleomorphic and gram negative?
- rickettsiae
- chlamydiae
what structure in mycobacteria make it impermeable to the gram stain?
mycolic acid
name the 6 bacteria that do not stain with a gram stain.
These Rascals May Microscopically Lack Color

- treponema
- rickettsia
- mycobacteria
- mycoplasma
- legionella pneumophila
- chlamydia
how do you stain for treponemes?
darkfield microscopy and fluorescent antibody staining
how do yo stain for legionella?
silver stain
what bacteria stain with giemsa stain?
- borrelia
- plasmodium
- trypanosomes
- chlamydia
what do you use the PAS (periodic acid-Schiff) stain for?
Tropheryma whippelii (Whipple's disease)
what is Ziehl-Neelsen stain?
acid fast stain
what do you use India Ink stain to stain for?
cryptococcus neoformans
what microbe requires chocolate agar with factor V (NAD) and factor X (hematin) to grow?
Hemophilus influenzae
what microbe requires Thayer-Martin media (VPN) to grow?
Neisseria gonorrhoeae
what is Thayer-Martin media (VPN)?
media with
- vancomycin: inhibits gram positive organisms
- polymyxin: inhibits gram negative organisms
- nystatin: inhibits fungi
what microbe requires Bordet-Gengou (potato) agar to grow?
bordetella pertussis
what is required to grow clostridium diphtheriae?
- tellurite plate
- loffler's media
what do you use Lowenstein-Jensen agar to culture?
Mycobacterium tuberculosis
what do you use Eaton's agar to culture?
mycoplasma pneumoniae
what media is required to culture legionella?
charcoal yeast extract agar buffered with cysteine
what media is used to culture fungi?
Sabouraud's agar
what is the definition of an obligate anaerobe? what are some examples?
- a bacteria the uses an O2-dependent system to produce ATP
- nocardia, pseudomonas aeruginosa, mycobacterium tuberculosis, bacillus
what part of the lungs does reactivated TB have a tendency to reappear? why?
- apices
- because this is where the highest O2 concentration is
name 3 conditions in which pseudomonas aeruginosa is likely to be seen?
- nosocomial pneuomnia
- burn wounds
- pneumonia in patients with cystic fibrosis
why are obligate anaerobes susceptible to oxidative damage?
they lack cataalse and/or superoxide dismutase
list 3 features of obligate anaerobes.
- generally foul smelling
- generally difficult to culture
- generally produce gas in the tissues (H2 and CO2)
where are anaerobes normally found?
normal part of the GI flora
which class of antibacterial agents are ineffective against obligate anaerobes? why?
- aminoglycosides
- because they requires O2 to enter the cell wall
which bacteria are obligate intracellular pathogens? why?
- rickettsia and chlamydia
- they cannot make their own ATP
list the facultative intracellular pathogens?
Some Nasty Bugs May Live FacultativeLy

- salmonella
- neisseria
- brucella
- mycobacterium
- listeria
- francisella
- legionella
what would a positive quellung reaction indicate?
the microbe is encapsulated
list the encapsulated pathogens.
- Klebsiella pneumoniae
- Salmonella
- Streptococcus pneumoniae
- Haemophilus influenzae type B
- Neisseria meningitidis
what does a capsule do for a bacteria?
serves as an antiphagocytic virulence factor
what are the urease positive microbes?
Particular Kinds Have Urease

- Proteus
- Klebsiella
- Helicobacter pylori
- Ureaplasma
which microbe contains Protein A? what is Protein A?
- staphylococcus aureus
- it binds to the Fc region of Ig and prevents opsonization and phagocytosis
which microbes contain IgA protease? what does it do?
- S. pneumoniae, H. influenzae type B, Neisseria
- destroys IgA in order for these bacteria to colonize respiratory mucosa
which microbes have M protein? what does it do?
- group A streptococcus (Streptococcus pyogenes)
- helps prevent phagocytosis
which is secreted from the bacteria: exotoxin or endotoxin?
exotoxin; endotoxin is part of the outer cell membrane
where on the bacterial genome are exotoxins encoded?
plasmids or bacteriophages
where on the bacterial genome are endotoxins encoded?
bacterial DNA
which type of bacterial toxin has a higher toxicity, endotoxin or exotoxin?
exotoxin has a high toxicity while endotoxin has a low toxicity
what are superantigens? how do they work?
- bacterial antigens that cause massive host immune system response
- they bind directly to MHC II and T-cell receptors simultaneously, activating large numbers of T cell to stimulate the release of IFN-gamma and IL-2
which microbes have superantigens?
- staphylococcus aureus
- streptococcus pyogenes (GAS)
which S. aureus superantigen causes toxic shock syndrome?
TSST-1
which S. aureus exotoxin causes staphylococcus scalded skin syndrome?
exfoliatin
which S. aureus exotoxin causes food poisoning?
enterotoxin
which S. pyogenes (GAS) superantigen causes toxic shock-like syndrome?
scarlet fever-erthrogenic toxin
what are ADP-riboslyating toxins? how do they work?
- these are A-B toxins
- the B component binds to a receptor on the surface of the host cell enabling endocytosis and the A component then attaches an ADP-ribosyl to a host cell protein (ADP-ribosylation) which alters cell function
which microbes have AB toxins?
- Corynebacterium diphtheriae
- Vibrio cholerae
- E. coli
- Bordetella pertussis
how does the corynebacterium diphtheriae AB toxin work?
it inactivates elongation factor, EF2, and causes pharyngitis and pseudomembrane formation in the throat
how does the vibrio cholerae AB toxin work?
it causes ADP ribosylation of a G-protein that stimulates adenylyl cyclase causing an increase in Cl- pumped into the lumen of the intestine and a decrease in Na+ absorption. as a result H2O moves into the lumen causing voluminous "rice-water diarrhea"
how does the E. coli AB toxin work?
there is a heat-labile toxin that stimulates adenylate cyclase and a heat-stabile toxin that stimulates guanylate cyclase both causing watery diarrhea
how does the B. pertussis toxin work?
it increases cAMP by inhibiting Galpha1. this causes a whooping cough and it inhibits chemokine receptor causing lymphocytosis
how does clostridium perfringes cause disease?
it releases an alpha toxin which causes gas gangrene
which bacteria causes a double zone of hemolysis on blood agar?
clostridium perfringes
how does clostridium tetani cause disease?
it releases a toxin that blocks the release of the inhibitory neurotransmitters GABA and glycine resulting in muscle tetani
how does clostridium botulinum cause disease?
it releases a toxin that blocks the release of acetylcholine causing anticholinergic symptoms
how does bacillus anthracis cause disease?
it releases a toxin part of which is an adenylate cyclase which is an edema factor
how does shigella cause disease?
it releases shiga toxin which cleaves host cell rRNA (inactivates the 60s ribosome) and enhances cytokine release resulting in HUS
what toxin on strep pyogenes (GAS) is the antigen for the ASO antibody test?
streptolysin O
which bacteria act as cAMP inducers?
- Vibrio cholerae
- Bordetella pertussis
- E. coli
- Bacillus anthracis
how does vibrio cholerae act on G-protein?
it permanently activates the Gs (turns on the on)
how does bordetella pertussis act on G-protein?
it permanently disables the Gi (turns off the off)
what is the only gram positive bacteria that has endotoxin (lipopolysaccharide)?
Listeria monocytogenes
what is bacterial transformation?
when a bacteria takes free DNA up from the environment
what is bacterial conjugation?
this is bacterial sex; 2 bacteria exchange a plasmid via pili
what is bacterial transduction?
when a bacteriophage accidentally cleaves bacterial DNA when synthesizes its own viral proteins and the bacterial DNA gets package into the new virus with the viral proteins. this bacteriophage then infects another bacteria spreading the accidentally packaged bacterial DNA
what is bacterial transposition?
when a segment of DNA moves from one location on the chromosome to another or to a plasmid
which bacterial toxins are endoced in a lysogenic phage?
- Shiga-like toxin
- Botulinum toxin
- Cholera toxin
- Diphtheria toxin
- Erythrogenic toxin of GAS (Strep. pyogenes)
name the bacteria: gram positive, cocci in clusters, catalase positive.
staphylococcus
name the bacteria: gram positive, cocci in chains, catalase negative.
streptococcus
name the bacteria: gram positive, cocci in clusters, catalase positive, coagulase positive.
staphylococcus aureus
name the bacteria: gram positive, cocci in clusters, catalase positive, coagulase negative, novobiocin sensitive.
staphylococcus epidermidis
name the bacteria: gram positive, cocci in clusters, catalase positive, coagulase negative, novobiocin resistant.
staphylococcus saprophyticus
name the bacteria: gram positive, bacilli. (hint there are 4 pathogens that fit this)
- clostridium
- corynebacterium
- listeria
- bacillus
name the bacteria: gram positive, cocci in chains, catalase negative, gamma hemolysis.
- enterococcus (E. faecalis or Group D strep)
- peptostreptococcus
name the bacteria: gram positive, cocci in chains, catalase negative, beta hemolysis, bacitracin resistant.
- Group B strep (Streptococcus agalactiae)
name the bacteria: gram positive, cocci in chains, catalase negative, beta hemolysis, bacitracin sensitive.
Group A strep (streptococcus pyogenes)
name the bacteria: gram positive, cocci in chains, catalase negative, alpha hemolysis, optochin sensitive, bile soluble.
streptococcus pneumoniae
name the bacteria: gram positive, cocci in chains, catalase negative, alpha hemolysis, optochin resistant, not bile soluble.
viridans streptococci (streptococcus mutans)
what is alpha hemolysis?
when the bacteria turn a blood agar green

remember Algea are green (A for alpha)
what is beta hemolysis?
when the bacteria cause complete clearing of the section of blood agar they are on
which organisms cause alpha hemolysis?
- strep pneumoniae (optochin sensitive)
- viridans streptococci (optochin resistant)

differentiate between they with a optochin sensitivity test
which organisms cause beta hemolysis?
- staph aureus
- strep pyogenes (GAS)
- strep agalactiae (GBS)
- listeria monocytogenes
what is gamma hemolysis?
where there is no clearing or color change in a blood agar

remember - Grandma does not work
what microbe is likely to cause recurrent infections in patients with chronic granulomatous disease (NADPH deficiency)? why?
- staphylococcus species (S. aureus, S. epidermidis, S. saprophyticus)
- they contain catalase which can break down what little H2O2 these people make
what microbe's virulence factor is Protein A? how does it work?
- staphlococcus aureus
- it binds to Fc-IgG inhibiting complement fixation and phagocytosis
what diseases are caused by toxins released by s. aureus?
- Toxic shock syndrome (TSST-1)
- scalded skin syndrome (exfolative toxin)
- rapid onset food poisoning (enterotoxins)
how does a person get food poisoning caused by s. aureus?
they ingest preformed enterotoxins
what is special about methicillin resistant staphylococcus aureus?
it is resistant to all beta-lactams
what staphylococcus species infects prosthetic devices and intravenous catheters? how?
- staphylococcus epidermidis
- they produce biofilms which allows them to adhere to things
what does streptococcus pneumoniae the most common cause of?
- meningitis in adults
- otitis media in children
- pneumonia
- sinusitis
what are the virulence factors in strep pneumoniae?
- capsule
- IgA protease
who most commonly gets infected with strep pneumoniae (pneumococcus)?
old people (>80 years old) and infants (<2 years old)
what will the sputum of someone with pneumococcus (strep pneumoniae) look like?
rusty or brown colored sputum
where is viridans streptococci specifically strep mutans normally found?
they are a normal part of the oropharynx
what is the most common lesion associated with strep mutans?
dental caries
what viridans streptococci species commonly causes bacterial endocarditis?
streptococcus sangius
what is another name for streptococcus pyogenes?
group A strep
what is the virulence factor of GAS (strep pyogenes) that can cause rheumatic fever?
M protein; body makes antibodies against the M protein on GAS. these antibodies can then cross react with self-antigens
what is the most common cause of meningitis in neonates?
streptococcus agalactiae (GBS)

remember B is for Babies
where are group B streptococci (Enterococci) normally found?
they are a normal part of the colonic flora
will penicillin treat a Enterococcus infection?
no, they are resistant to penicillin G
how is Lancefield group D streptococci differ from other group D streptococci?
they have differences in the C carbohydrate on the bacterial cell wall
what type of patient would you be worried about a streptococcus bovis infection? what would it cause?
- it can colonize the gut in patients with colon cancer
- this can cause subacute endocarditis and/or bacteremia
what will microscopy show when looking at corynebacterium diphtheriae?
gram positive rods with metachromatic (blue and red) granules
how does corynebacterium diphtheriae cause disease?
they have an exotoxin encoded by a beta-prophage. this exotoxin inhibits protein synthesis via ADP-ribosylation of EF-2
what will c. diphtheriae cause?
pseudomembranous pharyngitis with lymphadenopathy
is there a vaccine for c. diphtheriae?
yes, a toxoid vaccine
which bacteria can make spores under adverse conditions?
- bacillus anthracis
- clostridium perfringes
- clostridium tetani
- bacillus cereus
- clostridium botulinum
T or F: bacterial spores are metabolically active.
false, they are metabolically inactive
T or F: bacterial spores are resistant to destruction by chemicals and heat.
true
what is the only way to kill bacterial spores?
autoclave
how does clostridium tetani cause paralysis?
it produces a exotoxin called tetanospasmin which blocks glycine release from Renshaw cells in the spinal cord leading to spastic paralysis, trismus (lockjaw), and risus sardonicus
how does clostridium botulinum cause disease?
it produces a preformed heat-labile toxin that inhibits acetylcholine release at the neuromuscular junction
how do you get infected by clostridium botulinum?
- adults ingest the preformed toxin most commonly from improperly canned foods
- children ingest the bacterial spores most commonly from honey (floppy baby syndrome)
how does clostridium botulinum infection kill people?
paralysis of the diaphragm
how does clostridium perfringes cause disease?
it produces an alpha toxin called lecithinase which breaks down phospholipase in the cell membrane causing myonecrosis (gas gangrene) and hemolysis
how does clostridium difficile cause disease?
it produces a cytotoxin that kills enterocytes causing pseudomembranous colitis
who gets infections with clostridium difficile?
people who were on antibiotics especially if they were on clindamycin or ampicillin
what is the major symptom of clostridium difficile? how do you treat it?
- diarrhea
- metronidazole
what is the only bacteria with a polypeptide capsule?
bacillus anthracis
what is Woolsorters' disease?
inhalation of anthrax spores from contaminated wool
a patient comes in with black eschar (painless ulcers) surrounded by an edematous ring on his skin. he develops bacteremia and then dies. autopsy shows a gram positive spore forming rod. what is the most likely diagnosis? what caused the black eschar?
- bacillus anthracis
- lethal factor and edema factor, 2 toxins that anthrax produces
a women comes in with symptoms of the flu. she states that while at work sheering sheep she suddenly developed a fever and felt sick. you admit her to the hospital. she quickly develops pulmonary hemorrhage, mediastinitis, and goes into shock. what is the most likely diagnosis? how did she get this disease?
- woolsorter's disease (pulmonary anthrax)
- she inhaled the spores from contaminated wool
what are the 3 ways you can get listeria monocytogenes?
- ingestion of unpasteurized milk/cheese
- deli meats
- or vaginal transmission during birth
what is the purpose of listeria monocytogenes forming "actin rockets"?
they allow them to be intracellular microbes and move from cell to cell
what is the only gram positive bacteria with an endotoxin?
listeria monocytogenes
what is the major characteristic of listeria monocytogenes when visualized under microscopy?
tumbling motility
which fungi will gram stain? what will the gram stain result be?
- actinomyces and nocardia
- they both gram stain positive
where are actinomyces israelii normally found? what do they cause?
- they are a normal part of the oral flora
- they cause oral/facial abscesses that may drain through sinus tracts in the skin
where is nocardia asteroides found? what do they cause and in whom?
- found in the soil
- cause pulmonary infection in immunocompromised patients
how would you treat nocardia infections?
sulfa drugs
how would you treat actinomyces?
penicillin
what is the microbe that causes tuberculosis? how does it gram stain?
- mycobacterium tuberculosis
- it doesn't gram stain, you must use an acid-fast (Niehl-Zeelsen) stain
what is a primary complex in TB?
a primary exudative lesion + enlarged draining hilar lymph nodes
what is a gohn complex?
a TB granuloma with lobar and perihilar lymph node involvement
a patient comes in with fever, night sweat, weight loss, and hemoptysis. he admits to drinking about 12 "tall boys" of beer per day. what is the most likely diagnosis?
TB; the patient is an alcholic and the population at highest risk for TB is alcoholics
where are the most common extrapulmonary sites for TB to attack? which one is the most common?
- lymph nodes (most common)
- CNS
- vertebral bodies (Potts disease)
- renal
- GI
what part of the lungs is primary TB most commonly found?
usually the lower lobes
what part of the lungs is secondary TB most commonly found?
usually the upper lobes
who gets infected with mycobacterium avium complex?
immunocompromised people most commonly people with AIDS (this is an AIDS defining illness)
what is the second most common mycobacterium infection? what parts of the country is the commonly found?
- mycobacterium kansasii
- chicago, dallas, new orleans, and houston
what is the definition of multi-drug resistant TB?
resistance to isoniazid and rifampicin
what is the definition of extremely drug resistant TB?
resistance to isoniazid and rifampicin and second line drugs especially quinolones
what is catheliciden?
a potent, antimicrobial peptide made endogenously from vitamin D that helps to stem off TB
what organism causes leprosy (Hansen's disease)?
mycobacterium leprae
what are the 2 forms of leprosy?
- lepromatous
- tuberculoid
how does someone with lepromatous leprosy present?
- leonine facies
- diffuse lesions all over the body

this is the bad one
how does someone with tuberculoid leprosy present?
a few hypoesthetic nodules

this is the not so bad one
what causes the difference between tuberculoid leprosy and lepromatous leprosy?
- tuberculoid leprosy the patient has a good cell mediated response to the infection and for the most part can keep it under control
- lepromatous leprosy the patient has a failed cell mediated immune response and the bacteria can spread all over the body
what parts of the body does m. leprae preferentially infect?
skin and superficial nerves
what type of agar or media do you need to grow m. leprae?
it cannot be grown in any agar or media. the only hosts are humans and armadillos
what is the treatment for leprosy? what are the major side effects?
- long term oral dapsone
- hemolysis and methemoglobinemia
name the bacteria: gram negative, cocci, maltose fermenter.
Neisseria meningitidis
name the bacteria: gram negative, cocci, maltose nonfermenter.
Neisseria gonorrhoeae
name the bacteria: gram negative, coccoid rod. (hint: there are 4)
- Haemophilus influenzae
- Pasteurella
- Brucella
- Bordetella pertussis
name the bacteria: gram negative, rod, fast lactose fermenter. (there are 3)
- Klebsiella
- E. coli
- Enterobacter
name the bacteria: gram negative, rod, slow lactose fermenter. (there are 2)
- Citrobacter
- Serratia
name the bacteria: gram negative, rod, lactose nonfermenter, oxidase negative. (there are 3)
- Shigella
- Salmonella
- Proteus
name the bacteria: gram negative, rod, lactose nonfermenter, oxidase positive.
Pseudomonas
what agar is needed to grow lactose-fermenting bacteria? how will they appear on this agar?
- MacConkey's agar
- pink colonies
name the 5 lactose fermenting enteric bacteria.
- E. coli
- Klebsiella
- Enterobacter
- Serratia
- Citrobacter
what disease can be caused by gonococci?
- gonorrhea
- septic arthritis
- neonatal conjunctivitis
- pelvic inflammatory disease
- Fitz-Hugh-Curtis syndrome
how is gonococci spread?
it is a sexually transmitted infection
how is meningococci spread?
respiratory and oral secretions
what diseases does meningococci cause?
- meningococcemia
- meningitis
- Waterhouse-Friderichsen syndrome
what agar is needed to grow H. influenzae? what specifically does this agar have in it?
- chocolate agar
- factor V and factor X
how do you treat meningitis caused by H. influenzae?
ceftriaxone
what diseases are caused by H. influenzae?
- epiglottitis
- otitis media
- pneumonia
how is H. influenzae transmitted?
aerosol transmission
what is the vaccine against H. influenzae made from?
the vaccine contains the type B polysaccharide from the capsule conjugated with the diphtheria toxoid to cause an improve immune system response
how do you grow legionella pneumophila?
on charcoal yeast extract with iron and cysteine
what diseases are caused by legionella pneumophila?
- legionnaire's disease
- pontiac fever
what differentiates legionnaire's disease from pontiac fever?
legionnaire's disease is severe pneumonia and fever while pontiac disease is mild flu-like syndrome
how does legionella pneumonia stain?
weakly gram negative; use a silver stain
how is legionella pneumonia clinically detected?
presence of the antigen in the urine
how is legionella pneumonia transmitted?
aerosol transmission from environmental water source habitat; there is no person to person transmission
what is the treatment for legionella pneumonia?
erythromycin
name the 7 disease states that Pseudomonas aeruginosa can cause?
- wound and burn infections
- pneumonia in patients with CF
- sepsis
- external otitis (swimmer's ear)
- UTI
- Drug use and diabetic osteomyelitis
- hot tub folliculitis
what are the 3 major virulence factors produced by Pseudomonas aeruginosa?
- endotoxin which leads to fever and shock
- exotoxin A which inactivates EF2
you begin to take care of a patient on the burn unit. he was brought in a few days ago after suffering third degree burns to his arms while trying to light his grill. you notice that he has a blue-green color to part of his forearm and there is a grape-like smell. what is causing the color and smell of his arm? what will you do for this patient?
- the patient's burn wounds are infected with P. aeruginosa. the blue-green color is caused by pyocyanin a pigment produced by P. aeruginosa. the grape-like smell is also from the bacteria.
- aminoglycoside plus an extended-spectrum penicillin
which species are included in the enterobacteriaceae family?
- E. coli
- Salmonella
- Shigella
- Klebsiella
- Enterobacter
- Serratia
- Proteus
what toxin is produced by enteroinvasive E. coli? what does it cause?
- shiga like toxin
- dysentery; the microbe invades the colonic mucosa and the toxin causes necrosis and inflammation
what toxin is produced by enterohemorrhagic E. coli? what does it cause?
- shiga like toxin
- dysentery; the toxin alone causes necrosis and inflammation of the colonic mucosa
what toxin is produced by enterotoxigenic E. coli. what does it cause?
- labile and stable toxins
- traveler's diarrhea
how does enteropathogenic E. coli cause disease? what does it cause?
- it adheres to the apical surface of enterocytes, flattens the villi of enterocytes, and prevents absorption
- diarrhea usually in children
what are the 4 A's of Klebsiella?
- aspiration pneumonia
- abescess in the lungs
- alcoholics
- diAbetics
where is Klebsiella normally found? how does it cause disease, specifically pneumonia?
- it is a normal part of the intestinal flora
- causes pneumonia in alcoholics and diabetics when aspirated
what is the most pathognomic symptom of Klebsiella?
red currant jelly sputum
which has flagella: salmonella or shigella?
salmonella
which is more virulent: salmonella or shigella?
shigella
how are salmonella and shigella transmitted?
- food
- fingers
- feces
- flies
what do salmonella and shigella cause?
both invade the intestinal mucosa and cause bloody diarrhea
which can disseminate hematogenously: salmonella or shigella?
salmonella
how would a person with salmonella typhii (typhoid fever) present? how do you rid the body of the bacteria?
- fever, diarrhea, headache, rose spots on abdomen
- remove the gallbladder; salmonella typhii can remain in the gallbladder chronically
how is Yersinia enterocolitica usually transmitted?
- pet feces
- contaminated milk
- contaminated pork
where do you commonly see outbreaks of Yersinia enterocolitica? what does it cause?
- day care centers
- mimics Crohns or appendicitis
what causes the majority, 90% of duodenal ulcers?
helicobacter pylori
what does H. pylori infection put the patient at an increased risk for?
- peptic ulcers
- gastric adenocarcinoma
- lymphoma (MALToma)
how do you treat H. pylori infections?
triple therapy
- a proton pump inhibitor
- clarithromycin
- amoxicillin or metronidazole
name the spirochetes. (there are 3)
- Borrelia
- Leptospira
- Treponema
how do you visualize the spirochetes?
- Borrelia can be seen using Wright's or Giemsa stains (analine dyes)
- Treponema can be seen using darkfield microscopy
where would i find Leptospira interrogans? what is it shaped like?
- water contaminated with animal urine
- a question marked shaped bacteria
What is Weil's disease?
also called icterohemorrhagic leptospirosis, it is caused by leptospira interrogans and presents with severe jaundice and azotemia from liver and kidney dysfunction, fever, hemorrhage, and anemia
where is Leptospira interrogans most prevelant (what part of the world)?
the tropics
what are the 3 stages of lyme disease?
1. erythema chronicum migrans (target rash) and flu
2. neurologic manifestations (Bell's palsy) and cardiac manifestations (AV nodal block)
3. chronic monoarthritis and migratory polyarthritis
what causes lyme disease? how is it transmitted?
- Borrelia burgdoferi
- Ixodes ticks
what 2 animals are required for the entire life cycle of Borrelia burgdorferi? how do humans get this infection?
- mice (reservior) and deer
- Ixodes ticks
what is the treatment for lyme disease?
doxycycline or ceftriaxone
how does a Treponema pertenue infection present?
- yaws, an infections of the skin, bone and joints leading to healing keloids and severe limb deformities and characteristic facial disfigurement (destruction of the nasal bone and cartilage) after 5-10 years
where is Treponema pertenue found?
the tropics
what bacteria causes syphilis?
Treponema pallidum
what is the treatment for T. pallidum?
penicillin G
how does primary syphilis present?
painless chancre on the genitals
how does secondary syphilis present?
disseminated disease with constitutional symptoms, maculopapular rash on the palms and soles, alopecia areata, and condylomata lata
how does tertiary syphilis clinically present?
- broad based ataxia
- positive Romberg sign
- Charcot joints
- stroke without hypertension
what pathologic lesions does tertiary syphilis cause?
- chronic granulomas
- aortitis due to vasa vasorum (tree barking appearance)
- neurosyphilis (tabes dorsalis)
- argyll robertson pupil
what are the manifestations of congenital syphilis?
- saber shins
- saddle nose
- Hutchinson's teeth
- CN VIII deafness
- snuffles
- argyll robertson pupils
what are argyll robertson pupils?
- the pupil constricts to accommodation but is not reactive to light
- also called Prostitute's Pupil
which test for syphilis is the most specific, is positive earliest, and remains positive the longest?
FTA- Antibody
VDRL is a test for syphilis. what can cause a false positive VDRL test for syphilis?
- Viruses (mono & hepatitis)
- some drugs
- Rheumatic fever
- Lupus
- Leprosy
what infection is associated with cat scratches?
Bartonella (Cat Scratch Fever)
what infection is associated with the Ixodes tick?
Borrelia burgdorferi (Lyme disease)
what infection is associated with eating rabbits?
Francisella tularensis (Tularemia)
what infection is associated with rodents and flea bites?
Yersinia pestis (Plague)
what infection is associated with dog and cat bites?
Pasteurella multicoda
a woman comes in with a gray vaginal discharge that has a foul fish smell. what is the diagnosis?
Bacterial vaginosis caused by Gardnerella vaginalis
in what disease do you see Clue cells?
Gardnerella vaginalis (bacterial vaginosis)
how do you treat bacterial vaginosis?
metronidazole
why are Rickettsiae obligate intracellular organisms?
they lack CoA and NAD
how do you treat Rickettsiae infections?
doxycycline
what cause Rocky Mountain spotted fever? how is this pathogen transmitted?
- Rickettsiae rickettsii
- ticks
what causes endemic typhus? how is this pathogen transmitted?
- Rickettsiae typhi
- fleas
what causes epidemic typhus? how is this pathogen transmitted?
- Rickettsiae prowazekii
- human body louse
what causes Ehrlichiosis? how is this pathogen transmitted?
- Ehrlichia
- tick
what causes Q fever? how is this pathogen transmitted?
- Coxiella burnetii
- inhaled aerosols
a liverstock farmer comes in with interstitial pneumonia. what is the most likely diagnosis?
- Q fever (Coxiella burnetii)
a patient from New Hampshire comes in to the ER with a rash on the palms and soles, headache and fever. what is the most likely diagnosis? what is the causative agent? how did this patient acquire this disease?
- Rocky Mountain Spotted Fever
- Rickettsiae rickettsii
- a tick bite
what is the Weil-Felix Reaction?
a test for Rickettsiae infection. a positive test is when a patient's serum is mixed with Proteus antigens and anti-rickettsial antibodies cross-react and agglutinate
why is Chlamydiae an obligate intracellular organism?
they cannot make their own ATP
how do you treat Chlamydiae infections?
erythromycin, azithromycin, or tetracycline
what disease does Chlamydiae pneumoniae and Chlamydiae psittaci cause?
atypical pneumonia
what do Chlamydia trachomatis serotypes A, B, and C cause?
chronic infection and blindness in Africa
what do Chlamydia trachomatis serotypes D-K cause?
- urethritis/PID
- neonatal pneumonia
- neonatal conjunctivitis
what do Chlamydia trachomatis serotypes L1, L2, and L3 cause?
lymphogranuloma venereum
what causes granuloma inguinale? what is this disease often confused with?
- Calymmatobacterium granulomatis
- Lymphogranuloma venereum
a 22 year old college student presents with headache and a non-productive cough. CXR shows diffuse interstitial infiltrate. what is the most likely diagnosis? what caused this disease?
- Walking pneumonia
- Mycoplasma pneumoniae
how does Mycoplasma pneumoniae gram stain?
it doesn't. it has no cell wall
how do you treat Walking Pneumonia (Mycoplasma pneumoniae)?
tetracycline or erythromycin
where in the US would you find histoplasma capsulatum?
Mississippi and Ohio River Valleys
a 55 year old man presents with pneumonia. his wife says that he is in good health and as a matter of fact he just went on a cave tour 2 days ago. what is the most likely diagnosis?
Histoplasmosis (Histoplasma capsulatum)
where would I find Blastomyces dermatitidis?
states east of the Mississippi River
where would I find Coccidiodes immitis?
Southwestern US (specifically California)
where would I find Paracoccidiodes brasiliensis?
Latin America
a patient comes in with an inflammatory lung disease. you admit her to the hospital the infection disseminates to the skin and bones forming granulomatous nodules. microscopic examination of the nodules shows an organism with broad based budding. what is the most likely diagnosis?
Blastomycosis
a patient comes in and says he needs a physical. he admits that he hasnt been to the doctor in several years. you do a chest x ray and notice a diffuse infiltrate. the patient claims he has no symptoms and you don't notice any. what is most likely in this patient's lungs?
Blastomyces dermatitidis (it can cause a chronic infection that shows no symptoms
what causes Desert Fever? how do people get it?
- Coccidiodes immitis
- anything that throws the spherules into the air (earthquakes, dust storms, etc) and then the person inhales the spherules
what infectious pathogen has multiple budding that is sometimes called a captain's wheel formation?
Paracoccidiodes brasiliensis
name the systemic mycoses.
- Histoplasma capsulatum
- Blastomyces dermatitidis
- Coccidiodes immitis
- Paracoccidiodes brasilensis
what is a dimorphic fungus? which fungal infections are dimorphic?
- a fungus that exists as a mold in cold temperatures and a yeast in warm temperatures
- Histo, Blasto, Paracoccidiodes
a patient comes in with new, hypopigmented patches of skin. microscopic examination shows a fungal infection. what is the most likely diagnosis?
Tinea versicolor caused by Malassezia furfur
how do you treat superficial Candida albicans? how do you treat systemic Candida albicans?
- nystatin
- amphoteracin B
how can you tell the difference between diaper rash from irritation and diaper rash from Candida?
Candida will cause satellite lesions where as an irritant rash will not
how can you tell the difference between Aspergillus and Mucor?
Aspergillus has Acute angle branching (45 degrees) while Mucor has wide angle branching ( >90 degrees)
a patient comes in with symptoms of meningitis. he tells you that he has been using pigeon poop as fertilizer for his garden because it is free. he quickly gets worse and dies. during autopsy, a sample of his brain is stained with India Ink stain and it shows a soap bubble appearance under the microscope. what is the most likely diagnosis?
Cryptococcus neoformans
a patient comes in with a cough. chest x ray shows a diffuse bilateral lung infiltrate. his history is positive for HIV infection. what is your diagnosis? (hint there are 2)
- he has a pneumonia caused by Pneumocystis jiroveci
- you can also now diagnose him with AIDS because pneumocystis jiroveci is an AIDS defining illness
how do you treat a patient that has pneumocystis jiroveci.
trimethoprim and sulfamethoxazole
a woman comes in to your office because of a large pustule on her finger. she says that she was working in her rose garden 2 days ago and got pricked by a rose thorn. physical exam reveals nodules along the lymphatics that drain the finger. what is the most likely diagnosis? what is the treatment?
- Sporotrichosis or Rose Gardener's disease cause by Sporothrix schenckii
- treatment is itraconazole or potassium iodine
a group of campers have foul-smelling, fatty diarrhea after drinking some creek water during their camping trip. what is the most likely diagnosis?
Giardia lamblia
how will Giardia lamblia appear under the microscope?
a protozoa with owl's eye appearance
how do you treat Giardia lamblia?
metronidazole
patient has RUQ pain and dysentery. CT reveals liver abscess. you aspirate the liver abscess and it looks like anchovie paste. what is the most likely diagnosis?
Entamoeba histolytica
how do you treat Entamoeba histolytica?
metronidazole and iodoquinol
what do you see in the cytoplasm of the trophozoite of Entamoeba histolytica?
red blood cells
how do you get Entamoeba histolytica infections?
ingests the cysts from water
what does Cryptosporidium cause?
severe diarrhea in AIDS patients, mild, watery diarrhea in patients with intact immune systems
how do you acquire Toxoplasma gondii?
- in meat
- from cat poop
- congenital by crossing the placenta
what is the classic triad of congenital toxoplasmosis?
- chorioretinits
- hydrocephalus
- intracranial calcifications
how do you treat toxoplasmosis?
sulfadiazine plus pyrimethamine
what is the classic finding in a HIV patient with Toxoplasmosis?
ring enhancing lesions on CT/MRI
how do you get Naegleria fowleri? what is the treatment?
- swimming in fresh water lakes
- no treatment; you just die rapidly
how is Trypanosoma gambiense and Trypanosoma rhodesiense transmitted to people? what disease do they cause?
- Tsetse fly
- African Sleeping Sickness
how do you treat African Sleeping Sickness?
- Suramin for the blood borne Trypanosomas
- Melarsoprol for the CNS Trypanosomas
a 55 year old woman from Brazil comes to your office with dilated cardiomyopathy, megacolon, and megaesophagus. what is the most likely diagnosis?
Chagas Disease caused by Trypanosoma cruzi
how is Trypanosoma cruzi transmitted?
Reduviid bug (kissing bug)
how do you treat Trypanosoma cruzi?
nifurtimox
a patient comes in with spiking fevers, hepatosplenomegaly, and pancytopenia. he says that he was recently in the middle east. blood smear shows macrophages containing amastigotes. what is the most likely diagnosis?
Visceral leishmaniasis caused by Leishmania donovani
how do you treat Leishmania donovani?
sodium stibogluconate
how is malaria acquired?
Anopheles mosquito
what are the pathogens that cause malaria? which are the most common?
- Plasmodium vivax, ovale, malariae, falciparum
- P. vivax and P. falciparum are the most common
a patient comes in with a cyclic spiking fever, headache, anemia, and splenomegaly. examination of his blood shows RBCs with merozoites inside. you diagnose malaria. what is the mechanism behind the cyclic spiking fevers?
once every 24 hours the merozoites cause rupture of the RBCs causing the fever
what is the most severe cause of malaria? how do you treat it?
- P. falciparum
- chloroquine or quinine
how do you treat P. vivax or P. ovale malaria? why are these treated different than other forms of Plasmodium?
- chloroquine plus primaquine
- because vivax and ovale have dormant forms in the liver that primaquine will eliminate but chloroquine will not
what infections are transmitted by the Ixodes tick?
- Borrelia burgderfori (Lyme disease)
- Babesia
a patient has fever and hemolytic anemia. examination of his RBCs shows a maltese cross pattern. what is the most likely diagnosis? how did this patient get this disease? what is the treatment?
- Babesiosis caused by the protozoa Babesia
- bite from the Ixodes tick
- Quinine and clindamycin
woman comes in to the OBGYN office. she says she has vaginal itching and burning and a foul smelling, greenish discharge. speculum exam shows a strawberry cervix. what is the most likely diagnosis? how do you treat this?
- vaginitits caused by Trichomonas vaginalis
- Metronidazole
what is the most common protozoal infection in the US?
Entamoeba histolytica
what is the most common helminthic infection in the US?
Enterobius vermicularis (pin worms)
who gets pin worms? how do they get them? what are the signs/symptoms? how do you treat them?
- kids. most kids in the US will have a Enterobius vermicularis infection
- poor hygiene. pick up the eggs on their hands while playing and then eat without washing hands
- itchy butt
- Bendazoles or pyrantel pamoate
what is Loffler's Syndrome?
Eosinophilic pneumonitis due to a Ascaris lumbricoides infection
how do you treat giant round worm infection (Ascaris lumbricoides)?
bendazoles or pyrantel pamoate
how do you get Trichinella spiralis infections?
eating under cooked meat especially pork
how do you treat Trichinella spiralis?
bendazoles
how do you get a Strongyloides stercoralis infection?
the larvae penetrate the skin
what kind of symptoms do Strongyloides stercoralis cause?
this is an intestinal infection
- diarrhea
- vomiting
- anemia (decreases absorption of B12)
how do you treat Strongyloides stercoralis?
bendazoles or ivermectin
what are the 2 types of hookworms? how do you get infected by them?
- Ancylostoma duodenale and Necator americanus
- the larvae penetrate the skin of the feet
how do you treat hookworm infections?
bendazoles or pyrantel pamoate
list the nematodes that cause infections?
- Enterobius vermicularis
- Ascaris lumbrioides
- Trichinella spiralis
- Strongyloides stercoralis
- Ancylostoma duodenale
- Necator americanus
list the cestodes that cause infections?
- Taenia solium
- Diphyllobothrium latum
- Echinococcus granulosus
how do you get intestinal Taenia solium tapeworms?
ingestion of the larvae from under cooked pork
what does ingestion of eggs of Taenia solium cause?
- cysticercosis (a type of myositis)
- neurocysticercosis (life threatening and causes seizures)
- mass lesions in the brain (have a swiss cheese appearance)
how do you treat Taenia solium infections?
- Praziquantel
- bendazoles for neurocysticercosis
how do you get infected with Diphyllobothrium latum? what does it cause?
- ingestion of larvae from fresh water fish
- this is an intestinal tape worm that causes vitamin B12 deficiency resulting in anemia
how do you treat Diphyllobothrium latum?
Praziquantel
how do you get Echinococcus granulosus?
eggs in dog feces
how do you treat Echinococcus granulosus?
bendazoles
list the trematodes that cause infections.
- Schistosoma
- Clonorchis sinensis
- Paragonimus westermani
how do humans get infected with Schistosoma?
fresh water snails are the host and release them into the water where the cercariae penetrate human skin
how do you treat Schistosoma?
Praziquantel
What does chronic infection increase the risk for?
squamous cell carcinoma of the bladder
how do you get infected with Clonorchis sinensis?
eating under cooked fish
what does infection with Clonorchis sinensis cause?
- causes inflammation of the biliary tract which leads to pigmented gallstones
- also associated with cholangiocarcinoma
how do you treat Clonorchis sinensis?
Praziquantel
what infection do you get from eating under cooked crab meat?
Paragonimus westermani