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29 Cards in this Set
- Front
- Back
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difference between normal gut flora and enteric pathogens
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microbial virulence factors - toxins, attachment, invasiveness, motility, chemotaxis
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enterotoxin general mechanism
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cause net fluid secretion from intestinal mucosa - watery diarrhea
may lead to loss of tight juncitons |
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cytotoxin general mech
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cause destruction of mucosal cells - bloody diarrhea
shiga toxin, shigalike toxkin (EColi - O157:H7) |
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bacterial invasion general mech
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invade and destroy epithelium - mediated through O side chain of LPS
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enterotoxigenic E. coli (ETEC)
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travellers diarrhea
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enterohemorrhagic ecoli (EHEC)
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cytotoxin - shiga like
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enteroinvasive ecoli (EIEC)
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penetrates gut mucosa disrupts
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enteropathogenic ecoli (EPEC)
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focal adherance
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enteroaggregative ecoli (EAggEC)
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attachment and aggregates
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diffusely adherent ecoli (DAEC)
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diffuse adherence
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enteric host defense
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gastric acid
intestinal motility normal gut flora intestinal immunity - GALT - peyers patches, secretory IgA breast feeding personal hygiene |
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noninflammatory (type1) enteric infection
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proximal small bowl
watery diarrhea - due to electrolyte flux stool exam shows no fecal leukocytes ex: cholera - rice water stools, staph aureus |
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vibrio cholera
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curved aerobin g- bacillus
disease causing serogroups 01, 0139 serogroup 1 - classic, el tor |
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vibrio cholera clinical
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acute onset watery diarrhea -> dehydration, no fever, no abdominal pain
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vibrio cholera lab diagnosis
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stool sample - microscopy: look for darting motility
culture in TCBS media PCR |
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cholera toxin
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A-5B toxin
ADP ribosylation of adenylate cyclase secretion of electrolyte to lumen of intestine - water follows |
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cholera treatment
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rehydration therapy
antibiotics if severe |
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food poisoning vehicles
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PREFORMED enterotoxin, self limited
staph aureus - ham, poultry, potato salad, milk/cream stuff bacillus cerius - left over fried rice C. prefringines - meat, gravy C. botulinum - canned veg, fruit, fish |
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botulism routes
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g+ anaerobic bacillus
foodborn - ingestion of preformed toxin infant botulism - ingestion of spores wound botulism - spores into wound inhilation - does not occur in nature |
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botulism clinical
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abdominal pain, diarrhea
neruologic symptoms, blurred vision, bilateral canrial neruopathies, descending weakness respiratory distress |
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inflammatory (type 2) enteric infection
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location - colon
dysentery - small volume, bloody stools stool exam - PMNs shigella, salmonella, c.diff |
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shigellosis
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usual cause of bacillary dysentery
g- rod highly communicable - only a few organisms to cause disease invasion and toxin production |
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shigella clinical
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initial ab pain, fever
later - less fever, worse pain, bloody stool |
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what kind of drugs should you avoid in shigellosis
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antimotility agents
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salmonellosis
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vomitting, abdominal pain, nonbloody diarrhea
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salmonella source contamination
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eggs poultry mostly
beef, pork, dairy, turtles, rattlesnakes, marijuana |
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salmonella treatment
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only use antibiotics for neonates patients > 50yo, immunocompromised, and people with abnormal heart valves or endovascular grafts
ciprofloxacin, azithro, 3rd gen cephalosporin |
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penetrating (type 3) enteric infection
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location - distal small bowel
enteric fever stool exam - fecal mononuclear cells salmonella typhi, yersinia enterocolitica |
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salmonella typhi
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exclusive to humans
not human to human transmission - through contaminated food bacterial mediated endocytosis - survives in macrophage fever with inappropriate slow pulse treat with ciprofloxacin, azithro, ceftriaxone, chloramphenacol |
