GI bacteria Flashcards
C. difficile, gram + or -? aerobic/anaerobic?
C.Difficile = gram positive, anaerobic
think GI, so anaerobic
<3 colon
symptoms of C.difficile colonization?
some patients completely asymptomatic
others loose stools -> foul smelling diarrheas
C.difficile produces toxins that kill enterocytes - > leaky junctions between them -> inflammatory cells in the colon -> fever, high leukocyte counts, abdominal discomfort, etc
why are broad spectrum antibiotics a risk factor for C.diff?
broad spectrum kill normal GI flora, allowing C. diff to colonize intestines very well -> takes over
PPI - proton pump inhibitors -> raise pH in stomach - > easier to colonize for C. diff, since opportunistic
hospitals
immunocompromized
apart from diarrhea, what else are we worried about with C.diff?
pseudomembranous colitis (inflammation of the colon after antibiotic use, often associated with C.diff, diagnosed via sigmoidoscopy, sometimes has diffuse or nodular exudates on colon), toxic megacolon (surgery needed), colon rupture
very dangerous in immunocompromized patients
how do you treat?
mild-moderate: give antibiotics
Flagyl = metronidazole = treats anaerobes
vancomycin
BOTH VAN AND METRO ARE Crazy DIFFICULT modes of transport - c. Diff - Vancomycin and Metronidazol (Flagyl)
serious, like toxic megacolon - may need colectomy (colon resection)
recurrent disease:
fecal transplants very effective -> healthy flora introduced by NG tube or enema -> normal flora gets restored, C.diff dies down
what is the trade name of metronidazole?
Flagyl (think serious bacteria are very motile so they have flagella)
Which bacteria is the most common cause of travellers diarrhea?
ETEC - entero toxigenic e. coli
think T for travellers diarrhea
Which E.coli often causes bloody stool? Why?
antibiotic: y or no?
EHEC - enterohemorrhagic e.coli
has shiga-like toxin which inhibits ribosomes in epithelial cells and endocytes -> no protein synthesis -> cells die
-> hemorrhage -> bloody diarrhea
can also lead to hemolytic uremic syndrome (HUS) in rare cases - endothelial cells in the glomeruli get damaged, leading to renal failure -> hemolysis. Also toxin destroys endothelial lining of small capillaries and arterioles -> damage to RBCs as they squeeze through -> hemolysis
Treat both general EHEC and hemolytic uremic syndrome due to EHEC supportively (fluids, hemodyalysis). Antibiotics not recommended b/c EHEC would lyse and release toxin in large dose
what is hemolytic uremic syndrome in context of GI and bacterias?
EHEC (enterohemorrhagic E.coli) infestation can also lead to hemolytic uremic syndrome (HUS) in rare cases - endothelial cells in the glomeruli get damaged, leading to renal failure -> hemolysis. Also toxin destroys endothelial lining of small capillaries and arterioles -> damage to RBCs as they squeeze through -> hemolysis
Treat both general EHEC and hemolytic uremic syndrome due to EHEC supportively (fluids, hemodyalysis). Antibiotics not recommended b/c EHEC would lyse and release toxin in large dose
EHEC often called O157:H7 or STEC = shiga-toxin-producing E.coli
What are common E.coli infections?
GI - diarrheas, UTIs and pneumonia
What are symptoms of Salmonella typhi in GI?
antibiotic: y or no?
fecal oral route from human carriers (Typhoid Mary) or from flies transmitting from food => typhoid fever: fever, headache and rash. Diarrhea may not present at all, many patients actually experience constipation but if untreated INTESTINAL PERFORATION AND DEATH. SALMONELLA NEEDS ANTIBIOTICS (think fish so bad outcomes!)
Salmonella can colonize gallbladder -> very hard to eliminate it from there and may get cholecystectomy to eliminate it.
Is E.coli gram + or -ve?
Gram -ve
what effect does campylobacter jejuni have on GI? Gram + or -ve?
antibiotic: y or no?
Gram -ve
poultry - uncooked
most common cause of bacterial gastroenteritis in BC
intense diarrhea, 7 days, can be with fever, can be bloody esp. in kids.
test stool for ova and parasites, give antibiotics only if severe cases (often self-limited): macrolides and fluoroquinolones.
Giardia lamblia - what effects does it have on GI?
protozoa
fatty diarrhea 1-2 weeks, no invasion
imagine castle guard drinking crappy water and eating fatty foods - > getting fatty poops, can only improve if goes home on a metro (nidazole) (which is good for anaerobics and protozoas)
not invasive -> no fever
water -> organisms in the gut -> flattening of villi and loss of surface area for absorption -> steatorrhea, flatulence, greasy, floating stools.
asymptomatic common
diagnose through ova & parasites/PCR or ELISA or entero string test
Antamoeba histolica
liver abscesses (1% only - extraintestinal infection)
bloody diarrhea
asymptomatic (90%)
chronic disease mimicking IBD for years - historic disease - can drag on for yeas ~ histolic
contaminated water and food
if self limited, lasts 1 -2 weeks (spectrum above)
stool ova and parasites/ PCR or ELISA
metronidazole for trophozoite stage
