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62 Cards in this Set
- Front
- Back
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Leading cause of travelers diarrhea?
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Enterotoxigenic ecoli
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drinking h20 from streams and lakes you can get?
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Giardia
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Enteric Viruses
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rotavirus + norovirus
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Food Poisoning due to preformed toxins?
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Staph aureus enterotoxin + Bacillus cereus heat stable enterotoxin
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watery diarrhea...inflam or noninflam...what can cause it?
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Noninflammatory
Causes: entertic viruses (rotovirus + norovirus) ETEC, Vibrio cholerae, Parasites |
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When have diarrhea for a few weeks think of?
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parasites
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Inflammatory diarrhea caused by?
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shigella, campylobacter, salmonella, STEC, clostridium difficile, yersinia enterocolitica, vibrio parahaemolyticus, entamoeba histolytica
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Staph Aureus
-carrier? -due to? -incubation period? -symptoms? -duration? |
carrier - contamination of food by human carrier
incubation - 4 hrs...very short because to be infected dont need virus to grow symptoms - watery diarrhea, not bloody, severe vomit, ab pain, nausea, NO fever duration - 24 hrs |
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Staph Aureus enterotoxin?
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-heat stable
-stimulates cytokine release -acts on neuronal rec in upper GI, stimulates vomiting center |
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Bacillus Cereus
-toxin? |
-spore forming gram +
-toxin can be heat stable - emetic form heat labile - diarrheal form; stimulates cAMP --> hypersecretion of h20 and electrolytes |
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Bacillus Cereus Toxins
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Emetic Heat Stable form:
in rice, 6 hr incubation, n and v, cramps, lasts 8-10 hr Diarrheal Heat Labile from: in meat, vegs, more than 6 hr incubation, diarrhea, nausea, cramps, lasts 20-36 hrs |
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Clostridium different species
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anaerobic gram positive, spore forming
C. Difficle = ab associated diarrhea C. Peringens = food poisoning + gas gangrene C. Tetani = tetanus C. Botulinum = botulism |
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C. Perfringens
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Associated with meat dishes
-Heat resistant enterotoxin - released after ingestion of organism, or preformed in left overs -Alters membrane perm --> inc. fluid secretion = diarrhea -8-24 hr incubation -nausea, diarrhea, ab pain - 24 hrs |
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incubation for:
Staph Aureus Bacillus Cereus C. Perfiringens |
Staph Aureus - 4 hr
Bacillus Cereus Emetic Heat stable <6 Bacillus Cereus Heat labile >6 C. Perfringens 8-24 hr |
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Symptoms for:
Staph aureus Bacillus Cereus C. Perfringens |
Staph - nausea, vomit, diarrhea
BC Emetic - n,v,d BC Heat labile - ab cramp, diarrhea C. Perfringes - ab cramp, diarrhea |
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Food Source for:
Staph Auerus Bacillus Cereus C. Perfringens |
Staph - ham, poultry, potato/egg salad, mayo, cream pastry
BC Emetic - rice BC heat labile - meat, veg, bean, cereal C. Perfringesn - beef, poultry |
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Vibrio species
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Gram neg, curved rods
Highly Motile V. Cholera - O1 + O139 make cholera exotoxin and cause GI prob V. Parahaemolytic - watery diarrhea |
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Vibrio parahaemolyticus
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-cause: eat undercooked seafood
-5 to 7 hr incubation -watery diarrhea with blood -1 to 3 day duration -cramps, n and v, low grade fever, ha |
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V. Vulnificus
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-doesnt cause GI prob, causes wound infection
-systemic disease = die |
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Vibrio Cholera
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Nontoxigenic - GI prob from mild to severe watery diarrhea...no wound infection
Toxogenic - O1 + 0139 subtype prob after floods acid labile asymp to hypovol shock |
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cholera exotoxin
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toxin has a and b subunits...binds rec on cell (GM1 site is rec) once gets into cell and activates adenylyl cyclase to make more camp to inc secreation of Na, CL, K
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Enterobacteriacea
-types -characteristic |
-ubiquitous gram neg bact
-ferment glucose; oxidase neg -escherichia - uti, diarrhea, neonatal meningitis -shigella - dysentery -salmonella - typhoid fever -klebsiella - ut + pneumonia |
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E. coli virulen factors
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1.adhesins - pili and fimbriae
2. enterotoxins - heat labile and stable, shiga toxin |
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Which type ecoli is associated with causing hemolytic uremic syndrome?
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0157:H7 e.coli
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enterotoxigenic E.coli makes?
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watery diarrhea
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shiga toxin E.coli makes?
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dysentery
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ETEC pathogenesis
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Heat stable = STa + STb
STa- activates guanylate cyclase to ^cGMP STb - ^ca to ^bicarb to induce villous atrophy Heat Labile = LT 1 + LT2 LT1 -like cholera toxin... ^camp to alter electrolyte channel and secrete electrolytes and water |
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Leading cause traveler's diarrhea
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ETEC
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Mode of transmission of ETEC?
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contaminated drinking water, so wash fruits and veggies in bad water
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STEC most common subtype?
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0157:H7
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STEC transmission?
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beef contaminated during slaughter
direct contact with animals at petting zoo unpasteurized milk |
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STEC toxin?
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shiga toxin - Stx1 stx2
B subunit binds Gb3 = globotriaosylceramide A subunity enter cells and prevents binding of tRNA to ribosome |
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STEC clinical disease?
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-watery diarrhea becomes bloody
- ab pain -vom |
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intimin
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STEC adhesion factor
responsible for attachment and destruction of microvilli |
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HUS mao?
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STEC causes HUS:
enters enterocytes then spreads to adjacent cells to cause cell death and inflam response In young kids: Renal failure, thrombocytopenia, hemolytic anemia, htn |
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Enteropathogenic E.coli
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-less invasive then enteroinvasive e.coli
-causes infant diarrhea -attachment lesions = bfp, intimin, pedestals --> impaired absorption -watery diarrhea, vom |
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Enteroaggregative E.coli
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-protracted diarrhea - watery to mucoid
-No adhesion/effacement lesion - attaches via fimbriae, stim mucin, get mucousy diarrhea |
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Shigella Species
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nonmotile, non lactose fermenting
-person to person...NOT via animal watery diarrhea = s. sonnei Dysentery - s. dysenteria |
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Path of shigella?
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invades intestinal mucosa m cells...spreads to enterocytes...induces phagocytosis of enterocytes...formation of actin tails propel bacteria to other cells
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Shigella toxin?
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shiga toxin...same as STEC...can cause HUS, ulcers, abscess, inflam rxn
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Dysentery
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=inflam colitis + bloody diarrhea
kids <15 watery diarrhea to dysenteric diarrhea - small vol stools with blood and mucus, painful -cramping, fever, pain in lower ab -pseudomembrane formation |
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Salmonella Transmission
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exposure to undercooked chicken or eggs, exposure to turtles, rodents, picnic, food that was poorly refrigerated
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Salmonella pathogenesis
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-can persist in high fat, low water food and withstand high temp...thus hard to inactivate
-enterotoxin activates camp, adhesin causes ruffling of membrane, invades lamina propria of SI and induces an inflam response - some can cause systemic reaction |
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Enteric Fever carrier?
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human gb
bad water supply seen in travelers |
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Enteric Fever pathogenesis?
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S. Typhi survives in macrophages, inhibs resp burst.
Vi ag inhibs PMN phagocytosis causes bacteremia |
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Enteric Fever symptoms
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fever, ha, slow pulse
faint rash on ab and chest diarrhea hemorrhage |
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Yersinia
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-coccobacillus
-Y. Pestis -fever, ab pain, mesenterin lymphadenitis, diarrhea |
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Yersinia transmission
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- animal pathogen transmitted to human via consumption of bad food/water
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Yersinia Pathogenesis
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-invades M cells of peyer's patch and damages them and mesenteric LN
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Campylobacter
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-curved, gram neg rod
-major cause inflam diarrhea in US -normal flora of GI, GU in animals |
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Campylobacter transmission
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contaminated food/h20
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Campylobacter symptoms
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-dysenteric stools
-fever -low ab pain -associated with Guillain-Barre syndrome |
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Clostridium difficile
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-normal part intestinal flora
-watery bloody mucousy diarrhea to pseudomembranous colitis |
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Clostridium difficile toxin
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toxin a = enterotoxin: cell rounding, disruption of intercell junctions, hypersecretion of fluid, inflam
toxin b = cytotoxin: depolymerization of actin, loss of cellular cytoskeleton |
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Helicobacter
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-gram neg, curved rods
-urease - allows to be at low ph by neutralizing it VacA - induces apop Cag protein - reorg actin, activates multiple cell protein |
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Helicobacter transmission?
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person to person
colonization inc with age |
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most common cause gastritis, gastric ulcer, duod ulcer
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helicobacter
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helicobacter linked to
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gastric adenocarcinoma
malt |
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helicobacter pathogenesis
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avoid acid ph of stom - by getting below mucus layer
urease activity neut the acidic environ surface protein mediate adherence to epi cells |
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Gastritis
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infection limited to stom mucosa
induces inflam response and get abscess and ulcers...pain in upper ab, n and v can be asymp for years |
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dx. gastritis
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endoscope, biopsy, urea breath test
fecal leuk test test stool for lactoferrin |
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special agars for enteric org
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macConkey, Sorbitol, Hektoen enteric agar, campy BCA, TBCS
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