diarrhea Flashcards
watery secretory diarrhea pathogens or toxins are found in the
small bowel
blood or pus containing diarrhea pathogens are found in the
terminal ileum and colon
If there is tissue invasion we will get
fever
most common infectious cause of diarrhea is
unknown
virbrio cholerae, ETEC, non-typical salmonella, salmonella Typhi, shigella and EHEC are what type of bacteria?
gram negative rods
ADP ribosylation and constitutive activation of a G protein by cholera toxin results in high ___ leading to?
cAMP leading to decreased sodium absorption and less water absorbed and increased Cl- secretion and more water secreted
cholera results in
dehydration
treatment for cholera
- oral rehydration therapy
2. Vaxchora vaccine- live attenuated vaccine
The major cause of Traveler’s diarrhea
ETEC - Enterotoxigenic E. coli
ETEC 2 toxins that alter Na+ and Cl- transport
- LT- heat labile toxin
2. ST- heat stable toxin (cGMP)
incidence of typhoid fever vs non-typhoid salmonellosis
incidence of typhoid fever has decreased while the incidence of non-typhoid salmonellosis has increased
how does non-typhoid salmonellosis enter?
uptake by antigen-sampling M cells of the small intestine promoted by a type III secretion system
how does non-typhoid salmonellosis spread?
usually remain intestinally localized
how does non-typhoid salmonellosis damage?
submucosal replication triggers inflammation resulting in cl- secretion and watery diarrhea, sometimes with pus or blood
how does non-typhoid salmonellosis multiplication?
facultative intracellular pathogen that grows in the small intestine sub-epithelium
what about campulobacter jejuni and yersinia enterocolitica
campulobacter jejuni is highly prevalent and it is associated with guillan-barre an immune-mediated polyneuropathy that can lead to paralysis and yersinia enterocolitica is not prevalent but it can also lead to reactive immune-mediated arthritis
why is salmonella enterica similar to NTS?
why is it different?
enters M cells of the small intestinal epithelium via type III secretion system
infection is human to human while NTS infects other animals and is highly adaptable to spread and survive such as in the gallbladder
treatment for typhoid fever?
drug of choice is based on susceptibilities because resistance to penicillin and sulfonamides is growing but current choices is ceftriaxone and ciprofloxacin
shigellosis sucks why?
ID50 is ver low, you dont need much to get an infection because it is acid resistant
how does shigellosis migrate through epithelial barrier?
disrupts tight junctions
shigellosis is a crook and a thief why?
it steals our actin so that it can create a tail for itself making it mobile but remains localized to the GI tract
Shiga toxin from EGEC O157:H7 can result in
hemolytic-uremic syndrome which is the leading cause of kidney failure in children in the US
EHEC requires what for its colonization?
formation of actin pedestals
what is the shiga toxin?
an A-B model toxin that blocks protein synthesis–> cytotoxic
what is contraindicated in EHEC infection?
antibiotics because they can trigger prophage induction and thus supportive care only is suggested
the toxins, TcdA and TcdB that C. difficile synthesizes does what?
disrupt the intestinal epithelium
C. difficile infection causes (3)
- prolonged used of antibiotics
- eldery
- noncocomial infection- leading cause
gahhhhh antibiotic treatment in c.difficile results in a relapse
yep, because it disrupts the normal flora of the gut
