Quiz 3 GI Bugs Flashcards
Gram negative rod, found in Asia, Haiti, Africa. Large volume watery diarrhea, small bowel. Hypovolemic shock death. IV fluids and ORS. Azithro can shorten duration. Vibrio species are oxidase positive. Use TCBS agar, hardly anything grows on it but Vibrio. Vibrio like salt water and salt on plate helps it grow. Cholera does sucrose fermentation will turn colonies yellow.
Vibrio cholerae
-Gram positive rod, aerobic, spore-forming, enterotoxin causes diarrhea, cereulide toxin causes vomiting, goes away within 24 hours. Food poisoning, reheated fried rice.
Bacillus cereus
Food poisoning, gram positive cocci, has heat-stable toxin, goes away within 12 hours, cause from food prepared and left at room temp. Causes vomiting.
Staph aureus
Gram negative rod. Food poisoning from contaminated shellfish. Doesn’t ferment sucrose, stays green on TCBS agar. Oxidase positive.
Vibrio parahaemolyticus
Gram negative rod. Known as travelers diarrhea. Similar symptoms to Cholera but lower volume. Has watery diarrhea, cramps, malaise. Has heat labile toxin and heat stable toxins. ORS is huge, along with Azithro. Remember this is a small bowel, non-inflammatory. Also think galactosemia with regular E. Coli Sepsis. Use Cefotaxime for normal E. Coli in newborns.
Enterotoxigenic E. Coli (ETEC)
SSCYEC - Salmonella, Shigella, Campylobacter, Yersinia, EHEC, C. Diff.
What is the acronym for inflammatory diarrhea pathogens?
Gram negative rod, facultative anaerobe, motile. Found in eggs, poultry, water, reptiles and amphibians. Fever, abdominal pain, watery diarrhea. Less bloody than Shigella. Can cause endocarditis, mycotic aneurysm, osteomyelitis. Manage with ORS. Salmonella typhi is similar but is a bloodstream invasion without diarrhea. Green and Black on HE agar. Non-lactose fermenting on MacConkey. Produces H2S (black in tube).
Salmonella
Gram negative rod, facultative anaerobe, non-motile. Has a small inoculum, 10-100 organisms, doesn’t need much to cause disease. Can invade colon cells. Causes dysentery: bloody diarrhea, fever, abdominal pain. Treat with ORS. Green on HE agar. Non-lactose fermenting on MacConkey.
Shigella
Gram negative rod, “gull” shaped rod. Microaerophilic, needs oxygen, but not too much. Found in retail poultry. Watery/blood diarrhea similar to salmonella symptoms. Kept at 42 C because that is body temp of birds and that is where they come from. Post-infectious problems are reactive arthritis, paralysis. Catalase and oxidase positive.
Campylobacter
Gram negative rod, facultative anaerobe. Found in undercooked pork, similar symptoms to other inflammatory diarrheas. Has longer onset, and longer duration. Gives pseudoappendicitis and rheumatoid arthritis. CIN agar helps identify. Has bull’s eye on CIN agar.
Yersinia enterocolitica
Gram negative rod. Found in hamburger meat. Produces shiga toxin. 3-4 days after ingestion symptoms occur, bloody diarrhea, no fever though. Abdominal pain. Hemolytic Uremia Syndrome happens in 10% of patients. Also called STEC, shiga-toxin producing E. Coli. STEC does not ferment sorbitol, while other E. Colis do. Also, it is lactose-fermenting on MacConkey.
Enterohemorrhagic E. Coli (EHEC)
Gram positive rod. Anaerobic. Spore-forming and Toxic A and B. Is antibiotic associated, and fecal-oral. Diarrhea, fever, nausea, pseudomembranous colitis and toxic megacolon are key. Treated with metronizadole, fecal transplant, or colectomy. PCR may help detect asymptomatic carriers.
Clostridium Difficile
Gram negative rod. Motile, facultative anaerobe. Southeast Asia. Fecal-oral transmission, humans are the ONLY reservoir. Diarrhea not prominent. Fever but low heart rate which is opposite (pulse-temp disassoc). Causes rose spots. If left untreated, hallucinations, shock, perforations. Treat with azithro.
Salmonella typhi
Entamoeba histolytica is an amoeba, which is a protozoa. Can survive weeks outside the body. From ingestion of contaminated food/water, but the carriers are mostly asymptomatic. You get mild diarrhea to dysentery to colitis, but the main thing is a liver abscess. Treat with metronidazole, followed by a luminal agent. The cysts and trophozoites are passed in feces.
Entamoeba histolytica
Cryptosporidium parvum is a coccidian, which is also a protozoa. Involved in sporadic outbreaks in US. Is passed through fecal contaminated food/water, including recreational pools! Also found chronic in HIV patients and malnutritioned patients in third world countires. Gives you watery diarrhea, nausea, cramps. The immunocompromised have it prolonged and severe. Treat with ORS and Nitazoxanide if symptoms persist, but HIV patients are harder to treat.
Cryptosporidium parvum