Bugs Flashcards
S. aureus
shape & stain, toxins, symptoms, contraction
Gram + cocci in clusters preformed enterotoxins N/V, watery diarrhea rapid onset within 6 hours; rapid resolution 24-48 hours Contracted from ham, poultry, dairy, EGGS, CREAM PASTRIES, POTATO SALAD, MAYONNAISE
Bacillus cereus
shape & stain, toxins, symptoms, contraction
Gram + rods Preformed enterotoxins Vomiting (mainly), watery diarrhea Rapid onset within 6 hours; rapid resolution 24-48 hours Contracted from FRIED RICE, meats, veggies, dried beans, cereals
Clostridium perfringens
Gram + spore-forming rods
Preformed enterotoxins
Watery diarrhea (no fever or vomiting), crampy abd pain
Rapid onset within 8-16 hours;
Rapid resolution within 24-48 hours
Contracted from beef, ham, poultry, legumes, gravy (inadequately cooked)
Shigella spp
shape & stain, toxin, Symptoms, Contraction,
Dx, Tx, Complications
Gram - Rods, nonmotile
Shiga toxin
dystentery: bloody diarrhea (begins watery -> bloody with fever), abd cramps
Lasts 1-2 weeks
Tests: fecal leukocytes +, lactose - on stool culture
Tx: bismuth, ampicillin, fluoroquinolone, or trimethoprim/sulfamethoxazole
Complications: respiratory complaints and seizures (children), reactive arthritis, HUS
Reactive arthritis
Can’t see, can’t pee, can’t climb a tree
- conjunctivitis - discharge, erythema, burning, photophobia
- urethritis - dysuria, urgency, frequency, discharge
- arthritis - knees/ankles/feet
Salmonella typhimurium
shape & stain, symptoms, contraction, Dx, Tx, complications
gram -, non-lactose fermenting, motile, rod-shaped
watery -> bloody diarrhea, fever, abd cramping, N/V
Lasts 5-10 days, self-limited
Fecal leukocytes +
Contraction by food, esp EGGS, POULTRY, milk/dairy products, beef, shellfish or from animals - TURTLES, ducks, birds
Increased risk with immunocompromised (esp sickle cell)
Labs: stool culture
Do NOT give antibiotics
Complications: reactive arthritis, endocarditis, septic arthritis, osteomyelitis
Salmonella typhi
shape & stain, transmission, symptoms, Dx, Tx
gram - rod
International travel (humans are the only carrier), poor sanitation, fecal-oral
Sx: typhoid fever: systemic sustained febrile, high ever, weakness, headache, anorexia, RLQ pain, rash of flat rose-colored spots, diarrhea
Dx: samples of stool or blood; fecal leukocyte +
Tx: fluoroquinolones, ceftriaxone, azithromycin
Campylobacter jejuni
shape & stain, transmission, Sx, Dx, Tx, complications
gram - curved/spiral shaped rod
ingestion of raw/undercooked meat (POULTRY), diary (raw milk), birds and ducks are hosts, cross-contamination during food prep, contaminated water
Self-limited watery -> bloody diarrhea, fever, cramps abd pain
Dx: stool culture with campy blood agar, oxidase +, motile
Tx: supportive
Complications: 1-8 weeks post diarrhea: reactive arthritis, Guillian-Barre Syndrome
Vibrio cholerae
shape & stain, Sx, transmission, Dx, Tx
gram - bacilli, anaerobic, curve/comma shaped with flagellum
N/V, abd cramping, profuse watery (rice water) diarrhea, dehydration
12-48 hour incubation
waterborne illness (saltwater); eat raw oysters, sewage)
Duration: 1 week
Dx: stool microscopy
Tx: rehydration, antibiotics
Vibrio Parahemolyticus
shape & stain, toxin, transmission, Dx, Sx
gram - bacilli
cytotoxin production
Sx: N/V, abd cramps, watery -> bloody diarrhea
Dx: fecal leukocyte +, stool culture
Lasts 2-5 days
Sea-food associated: shellfish, oysters, shrimp
Vibrio Vulnificus
shape & stain, transmission, Sx
gram - bacillus
transmitted in coastal salt water through open wounds, and eating raw shellfish (oysters)
Sx: vomiting, diarrhea, abd within 16 hours of ingestion, bullies skin lesions
*life-threatening in immunocompromised (esp cirrhosis and hemochromatosis)
Aeromonas hydrophila
shape & stain, transmission, Sx, Tx
gram -, non-spore forming, rod-shaped, motile
fresh water environment, eating fish or shellfish, foot and ankle wounds in water
Sx: necrotizing fasciitis, cholera-like (watery rice water stools) OR bloody mucoid stools
Tx: ampicillin
Causes of Travelers diarrhea
most common = ETEC
Others: campylobacter (Asia), salmonella, shigella, aeromonas, EAEC, coronavirus, Giardia (Russia, campers, backpackers, swimmers in wilderness), Cyclospora (Nepal), Norovirus (cruise ships)
ETEC
shape & stain, transmission, Sx, Dx, Tx
gram - rod
ingestion of contaminated food or water
Sx: N, occasional fever & vomiting, watery diarrhea
Sudden onset, 3-6 day duration
Dx: fecal leukocyte -
Tx: Antibiotics (trimethoprim/sulfamethoxazole, doxycycline, ciprofloxacin), bismuth
EHEC
shape & strain, toxin, transmission, Sx, Tx, complications
(O157:H7) gram - rod, shiga-toxin
food-borne: undercooked meat, raw veggies, raw milk, unpasteurized apple cider
animal contact
Sx: watery -> bloody diarrhea -> ischemic colitis, no fever, peripheral leukocytes +, fecal leukocytes +
Tx: supportive, rehydration
Complications: HUS 5-10 days into course; more likely in kids and if treated with antibiotics
Other E. coli
EAEC - persistent diarrhea in kids
EPEC - infantile watery or bloody diarrhea
EIEC - fever, abd pain, watery -> bloody diarrhea with leukocytes (dysentery)
Yersinia enterocolitica
shape & strain, transmission, Sx, Dx, Tx, complications
gram - coccobacilli
transmission by contaminated food/water or dairy, contaminated domestic animal feces
Sx: bloody diarrhea, fecal leukocytes +, fever, cramps, N/V, Abd pain & pharyngitis
Duration 10-20 days
Dx: stool/blood cultures
Tx: supportive care
Complications: rash, reactive arthritis
Note** - higher risk in those with derangements of iron metabolism, diabetes, and preexisting GI disorders
Note** - can mimic appendicitis
Listeria monocytogenes
shape & strain, transmission, Sx, Dx, Tx, Complications
gram + rod
get from contaminated food (raw milk, unpasteurized diary, and deli meats)
Sx: fever, non-bloody diarrhea, headache, N/V 2-3 days duration
Dx: blood culture or CSF, stool cultures
Tx: ampicillin and trimethoprim/sulfamethoxazole
Complications: causes meningoencephalitis and listeria placentis
- Note it has a predilection for pregnant women, extremes of age, immunosuppressed, and those with hemochromatosis
- Note that this can grow at cold temps
Clostridium difficile
shape & strain, toxin, transmission, Sx, Dx, Tx, complications
anaerobic, gram +, spore-forming bacillus
Cytotoxin production (exotoxin mediated)
Transmission: within last 2 months - hospital stay or ill contact? antibiotic use? Especially clindamycin, cephalosporins, and fluoroquinolones? PPI?
Sx: watery diarrhea, abd pain, fever, peripheral leukocyte +, pseudomembranes on colonic mucosa
Dx: stool - PCR for toxin
Tx: PO or IV metronidazole, PO vancomycin
Complication: toxic megacolon
Rotavirus
type, age, transmission, Sx, Dx, Tx
double stranded RNA virus
infants (children < 2), can occur in adults
spread via fecal-oral
Sx: vomiting and watery diarrhea, severe dehydration, fecal leukocytes -
symptoms begin within 72 hours and last 2-3 days, up to 5
Dx: viral culture or PCR, “wagon wheel” appearance on electron microscopy
Tx: supportive care
- Note: death can occur by dehydration
- Note: most common cause of acute diarrhea in infants
Adenovirus
type, age, Sx, Dx, Tx
double stranded DNA virus children Sx: fever, chills, myalgias, sore throat, watery diarrhea, vomiting, conjunctivitis, pharyngitis prolonged course (10 days) Dx: viral culture Tx: supportive
*Note: most common cause of viral conjunctivitis in children
Norwalk/Norovirus
type, age, transmission, Sx, Tx
small non-enveloped RNA virus
older children and adults
fecal-oral transmission; outbreaks via contaminated food, water, person-person
Sx: vomiting, watery diarrhea (4-8 stools/day)
symptoms within 24-48 hours, lasts 3 days
Tx: supportive care
*Note: strong association with nursing homes, child care centers, schools, and CRUISE SHIPS