1. Vibrio cholerae Gammaproteobacteria Gram-negative Comma-shaped
D. Hagman F2013
Modified by DYH
Vibrio cholerae
Gammaproteobacteria
Gram-negative
Comma-shaped
Two circular chromosomes of DNA
Approximately 4 million base pairs combined
Single, polar flagella
Some strains cause cholera
Electron micrograph image of a Vibrio cholerae bacterium by Leodotia Pope, of the Department of Microbiology at the University of Texas at Austin

2. Pathogenicity of V. cholerae
D. Hagman F2013
Modified by DYH
Pathogenicity of V. cholerae
Enters digestive tract through consumption of contaminated water or food
Contaminant usually the feces of a person infected by V. cholerae
N-methylphenyl-alanine pili allows the bacterium to adhere to intestinal epithelium
Embeds itself in the microvilli of intestinal epithelial cells
Secretes cholera toxin, a type III exotoxin
Neuraminidase spreading factor is also secreted to help cholera toxin bind to and penetrate the enterocytes, as it degrades neuraminic acid, a monosaccharide that holds the intestinal mucosa together
Cholera toxin stimulates the mucosa of the intestines to rapidly release fluids, causing vomiting and diarrhea which facilitates the transmission of the bacteria to other hosts
LD50 of the toxin is 250 μg/kg body weight
Untreated, death by dehydration is common