132 GI Pathogens Flashcards
most common causes of food-borne illnesses in US - bacterial? parasite? viral?
Campylobacteria (bacterial)
Giardia lamblia (parasite)
noroviruses (viral)
inflammatory diarrhea vs noninflammatory diarrhea
inflamm - mucous or blood from mucosa tissue destruction by pathogen;RBC, WBC + fever + incubation period of 2-4 days
noninflamm - watery stool without blood; due to toxins/virus NOT invasion into musosa; shorter incubation (1-12 hours); No fever
noninflammatory diarrhea - most common causes
vibro cholerae Enterotoxigenic E Coli Clostridium Bacilius cereus Staph Aureus Rotavirus Norovirus Giardia Crytpsporidium
vibro cholerae - shape/appearance? where does it live in environment? What are the types?
gram negative rod (“comma shaped”)
salt water in marine crustaceans
2 biotypes - El Tor (less severe) and Classic
cholera toxin - what encodes? what type of toxin? what does it increase in the cell? what does this activate?
encoded by phage
AB toxins (A is active, B is binding subunit)
activates enzyme increasing cAMP
activates CFTR channel –> increased Cl secretion and decreased Na uptake
cholera - clinical disease; death? how acquired? stool appearace? fever? oxidase +/-? treatment?
severe dehydration and death in 12 hours –> need massive amount of IV fluid
acquired via raw fish or water
stool is watery with mucus flecks
negative fever
oxidase+
IV + antibiotics
Clostridium perfringens appearance/stain? symptoms? duration? treatment?
Anaerobic gram + bacillus
food poisoning –> diarrhea + cramping without vomiting
<24 hours - self limited
dont need antibiotics
Bacillus cereus appearance/stain? toxins? found in what? length? treatment?
Gram + rod
2 toxins –> vomitting + watery diarrhea
toxins found in rice
< 24 hours –> dont need antibiotics
Staph Aureus causes what? symptoms and length? found in what? treatment?
food poisoning from heat stable toxins (A–>E)
cause wide spread outbreaks
vomiting + diarrhea < 10 hours
creams, potato salad, mayo
illness is from toxin so no antibiotics
rotovirus
who gets infected?
symptoms?
common world wide - everyone gets infected
vomiting then diarrhea w/ fever (exception to noninflam diarrhea rule)
**Everyone rotates through rotovirus and rotates through symptoms (vomiting –> diarrhea + fever)
Noroviruses
spread?
symptoms?
Fecal-oral + contaminated food/water
nausea, vomiting, diarrhea
24-48 hours (no treatment required)
Giardia lamblia type? who gets it? symptoms and duration? Rx?
parasite
fecal - oral –> campers
2 forms - trophozoites + cyst in environment
1-4 weeks
diarrhea, bloating, gas
Rx - metronidazole, furazolidone
traveler’s diarrhea - common cause and course?
enterotoxigenic E Coli is most common cause
short lived and self limited
inflammatory diarrhea
shigella salmonella campylobacter enterhemorrhavic E Coli Yersinia C. Diff Entamoeba histolytica
Shigella appearance/stain? spread? spread? type of diarrhea?
gram negative rods (closely related to E Coli)
tolerates stomach acid –> fingers, food, flies, feces, fomites (forks)
invades colon via M cells –> enterocyte spreading via host actin tails (like listeria)
mild watery diarrhea –> blood and pus w/ pain diarrhea
