Which of the following bacteria grows better in alkaline pH?
Ans. a (Vibrio cholerae). (Textbook of Microbiology by Anantanarayan, 6th/281)VIBRIO CHOLERAE# Gram-negative, strongly aerobic, Pleomorphic bacteria.# Vibrio lyse when injected intraperitoneally into specifically immunized guinea pigs (Pfieffer's phenomenon).# 'Fish in stream' appearance.# Darting motility (swam of gnats).# Grow better in alkaline medium.# NaCl required for optimal growth.# Bile salt agar# TCBS agar selective media(AIIMS Nov 2007)# Alkaline peptone water--enrichment media# "Cholera red" reaction -Indole is formed & nitrates are reduced to nitrites.# Vibrio cholerae toxin permanently activates Gs, causing rice-water diarrhea. ADP ribosylation of G protein stimulates adenylyl cyclase; -pumping of Cl into gut and -Na+ absorption. H2O moves into gut lumen; causes voluminous rice-water diarrhea.
Vibrio cholerae
Pseudomonas
Shigella
Salmonella
Vibrio