Flashcards in Enteric Infections Deck (53)
Define: secretory diarrhea
- what are the features?
- Watery diarrhea w/o fever or with minimal fever.
- Continues despite increasing intake of food and water
- mid abdominal pain
Define: Inflammatory diarrhea
- mucoid like diarrhea
- accompanied by fever
- may often be bloody and have WBC in the stool
- lower abdominal and rectal pain
Where does secretory diarrhea originate in the GI tract
What are 5 examples of causative pathogens of secretory diarrhea?
1. Vibrio cholera
3. E. coli (ST or LT)
What are 5 examples of causative pathogens of inflammatory diarrhea?
3. E. coli (EHEC/STEC)
4. Entamoeba histolytica
5. C. difficile
What are the two toxins that C. diff produces? Which is more pathogenic?
Toxin A (enterotoxin) and B (cytotoxin)
- Toxin B is more pathogenic
What are 2 medication types that increase risk for C. diff?
1. broad spectrum antibiotics
What is the diarrhea like with C. difficile?
watery and foul smelling (like a barn)
What is the leukemoid reaction?
phenomenon of an increase in WBC count that mimics leukemia but is due to infection
- common in C. diff
What is the treatment approach for C. diff?
1. Stop unnecessary antibiotics
2. Metronidazole (IV or oral) and Vancomycin (oral only)
3. Stool transplant to replenish to replenish microbiota
what are 3 virulence factors that pathogenic E. coli have?
1. Fibriae: allow for colonization
2. Adhesions: allow for cell invasion
3. Toxins: both endo and exo
Shiga toxin is an example for what kind of toxin?
Exotoxin = secreted
What is ETEC and what specific pathogenic adaptations does it have?
Enterotoxigenic E. coli
1. fimbriae for attachment
2. Heat labile (LT) toxin similar to cholera
3. heat stable toxin (ST)
What is the clinical syndrome for ETEC diarrhea?
mild water diarrhea and nausea but no vomiting for 1-4 days
What is the pathogenesis of ETEC diarrhea?
ingestion of fecally contaminated food/water with 10^8-10 bacteria needed to cause disease
What is the treatment for ETEC diarrhea?
What are EHEC and STEC?
They're the same thing
enterohemorrhagic e. coli and shigatoxin producing e. coli
What are the virulence factors specific to EHEC/STEC
The shiga toxin (A/B) toxin
- acts on ribosomes to block protein synthesis leading to cell death
- has preference for enterocytes and endothelial cells in the kidney
What is the clinical syndrome of EHEC/STEC?
vomiting, diarrhea (often bloody), and abdominal pain
for children: 5-10 days later can develop lethargy, anemia, oliguria = hemolytic uremic syndrome
What are the two forms of salmonella?
non-typhoidal and typhoidal
What are the forms of non-typhoidal salmonella? What kind of illness do they cause?
Enteritidis and thyphimurium
- usually not invasive, self resolving disease
What are the forms of typhoidal salmonella? What kind of illness do they cause?
Typhi and parathyphi
- cause invasive disease with fever and bacteremia which is fatal if not treated
what are the typical reservoirs of non-typhoidal salmonella?
reptiles and chickens
What is the clinical picture of non-typhoidal salmonella?
Acute diarrhea with fever and abdominal pain that resolves within 4-7 days
What is the reservoir of typhoidal salmonella?
What are the clinical symptoms of typhoidal salmonella disease?
Not always diarrhea! Can be constipated
- can lead to ileus and perforation
Long fevers + rash, headache
Where can salmonella typhi reside in the body dormant
What is the virulence factor of typhoidal salmonella?
Vi capsular antigen which prevents phagocytosis
What is the treatment for typhoidal salmonella?
antibiotics based on local resistance