Term
| What are enterbacteriaceae, Vibronaceae, pseudomonadaceae, and Bacteroidaceae collectively called? |
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Definition
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Term
| Which enterics can and cannot ferment lactose? |
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Definition
can: E. coli, most enterobacteriaceae
cannot: Salmonella, Shigella, Pseudomonas aeruginosa |
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Term
| Which media can grow lactose-fermenting gram(-) bacteria? |
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Definition
* EMB agar: kills gram(+), turns deep purple/black. E. coli has metallic green sheen
* MacConkey agar: kills gram(+), turns pink-purple |
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Term
| What are 3 major surface antigens in the enterics? |
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Definition
* O antigen: most external component of LPS
* K antigen: capsule that covers O antigen
* H antigen: makes up the subunits of the bacterial flagella |
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Term
| What are virulence factors of Escherichia coli (family enterobacteriaceae)? |
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Definition
* mucosal interaction (pili, invade epithelial cells)
* exotoxin (heat-labile and stable toxin; shiga-like toxin)
* endotoxin (lipid A of LPS)
* iron-binding siderophore |
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Term
| What diseases are caused by E. coli? |
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Definition
* diarrhea
* UTI
* neonatal meningitis
* gram(-) sepsis |
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Term
| How do LT and ST of E. coli cause rice-water like diarrhea (cholera-like)? |
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Definition
| exotoxins inhibit the reabsorption of Na+ and Cl-, stimulate the secretion of Cl- and HCO3-. Water follows |
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Term
| How does Shiga-like toxin of E. coli cause hemorrhagic diarrhea? |
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Definition
| The toxin inhibits the 60S ribosome in the intestinal epithelial cell |
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Term
| What does enteroinvasive E. coli cause? |
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Definition
diarrhea with blood and WBCs, fever.
Shares plasmid with Shigella bacteria |
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Term
| With O antigen, w/o H antigen (nonmotile), causes sepsis, UTI, pneumonia with bloody sputum. Which bacteria? |
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Definition
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Term
| Motile, has cross-reacting antigens with rickettsia, alkaline urine (urea --> NH3 + CO2)... which bacteria? |
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Definition
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Term
| How do you distinguish Shigella from E. coli and Salmonella? |
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Definition
Shigella: nonmotile, doesn't metabolize lactose, doesn't produce H2S
E. coli: motile, metabolize lactose
Salmonella: motile, doesn't metabolize lactose, produce H2S |
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Term
| T/F: is Shigella part of normal flora? |
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Definition
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Term
| Where do Salmonella reside? |
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Definition
| Animals' GI tracts (except for Salmonella typhi) |
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Term
| Which 4 disease states do Salmonella cause? |
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Definition
* typhoid fever: Salmonella invade lymph nodes in addition to GI epithelial cells. Facultative intracellular parasite
* carrier state: Salmonella typhi in gallbladder
* sepsis
* gastroenteritis (diarrhea): watery or mucous. Antibiotics don't shorten the duration |
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Term
| Treatment of typhoid fever? |
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Definition
| Ciprofloxacin or ceftriaxone |
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Term
| Why are patients with sickle-cell anemia prone to Salmonella osteomyelitis (bone infection)? |
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Definition
| No spleen --> no macrophages/PMN to opsonize (Vi antigen) and phagocytose the bacteria |
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Term
| Which bacteria? Non-enterics, reside in animals, survive refrigerator, virulent factors (invasion of epithelium and lymph nodes, entertoxin ~ST) |
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Definition
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Term
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Definition
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Term
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Definition
| bacteria attach (not invade) GI epithelial cells and secrete cholera toxin, choleragen, which results in watery diarrhea. Dehydration causes death. |
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Term
| Choleragen has the same mechanism as E. coli's LT toxin. How are they encoded? |
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Definition
Choleragen: on the chromosome
E. coli's LT: plasmid |
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Term
| What is the mechanism of choleragen? |
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Definition
| A subunit activates G-protein. Increased cAMP stimulates secretion of Na+ and Cl-, inhibits reabsorption of Na+ and Cl- |
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Term
| What is the leading cause of diarrhea in Japan? |
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Definition
| Vibrio parahaemolyticus infection. From uncooked seafood, sushi. |
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Term
| Three most common causes of diarrhea in the world? |
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Definition
* Campylobacter jejuni
* E. coli
* Rotavirus |
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Term
| Symptoms of Campylobacter jejuni? |
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Definition
| fever, headache, abdominal cramps, and BLOODY, loose diarrhea |
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Term
| What is the most common cause of duodenal ulcers and chronic gastritis (inflamed stomach)? |
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Definition
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Term
| Which bacteria: obligate aerobic (non-lactose fermenter), green and blue pigment, grape-like scent, exotoxin A |
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Definition
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Term
| Why is it important to know Pseudomonas aeruginosa? |
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Definition
* Infects only sick, immunocompromised patients in the hospital
* Resistant to almost every antibiotic |
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Term
| Infections caused by Pseudomonas aeruginosa? |
|
Definition
Burns
Endocarditis
Pneumonia
Sepsis
External malignant otitis media
UTI
Diabetic osteomyelitis
cOrneal infections |
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Term
| Which bacteria: no endotoxin (no lipid A), with capsule, obligate anaerobic, gram(-) rod, resides in GI tract, causes abscesses in the peritoneal cavity |
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Definition
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Term
| gram(+) anaerobes, part of normal flora of the mouth, vagina, and intestines? |
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Definition
| Peptostreptococcus, Peptococcus |
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