Vibrio/Campylobacter/Helicobacter Flashcards
What are the characteristics of non-inflammatory diarrhea?
No fecal WBC’s, small intestine, watery diarrhea
What are some of the causes of non-inflammatory diarrhea?
- Toxigenic bacteria, e.g. enterotoxigenic E. coli, V. cholerae
– Produce toxin affecting chloride secretion and sodium absorption
- Viruses cause death of enterocytes
- Protozoa in small bowel
- Bacteria – preformed toxin in food
What are the characteristics of inflammatory diarrhea?
Fecal WBC’s, large intestine, low volume of stool with mucus, blood and pus
What are some of the causes of inflammatory diarrhea?
- Bacteria – Shigella, Campylobacter, E. coli
- Protozoa – Entamoeba histolytica
- Toxin – Clostridium difficile, enterohemorrhagic E. coli
What is the adherence factor of V. cholera?
Tcp pili – Toxin coregulated pili
What conditions does V. cholera grow in?
Alkaline conditions
What are some characteristics of the metabolism of V. cholera?
Facultative anaerobe
Oxidase positive
What are the functions of ToxT/R/S for cholera?
- ToxS–membrane sensor
- ToxR–activates a number of genes including ToxT
- ToxT–activates tcp group and others
What is the main origin place of most cholera?
India and SE Asia.
What amount of cholera ingested is required for inoculation?
10^8 which is a relatively high amount
What is the mechanism of the cholera toxin?
ADP-ribosylating toxin that leads to the constant activation of AC which produces excess amounts of cAMP. cAMP promotes the secretion of Cl- and will inhibit the absorption of Na+ and Cl-
What is an important mediator of cholera immunity?
IgA
What are the clinical manifestations of cholera?
- Nonspecific prodrome: abdominal discomfort
vomiting, loose stools
- PROFUSE WATERY DIARRHEA
- No fever
- Stool is clear, odorless, “rice water”
How is oral rehydration for cholera achieved?
Administration of glucose alongside electorlytes
What antibiotic is used to treat cholera?
Doxycycline in most countries. Azithromycin for women and children.
