The Vibrio genus contains motile, Gram-negative bacteria that are obligate aerobes. Vibrio rods have a recognizable curved shape and a single polar flagellum. Although Vibrio species are non-invasive pathogens, they cause some of the most serious cases of diarrhea and thousands of people die from infection annually. These waterborne organisms are transmitted to humans via infected water or through fecal transmission. Thus, in countries with poor sewage or water treatment cholera is sometimes seen in epidemic proportions.
Cholera is characterized by severe diarrhea which has a rice-water color and consistancy.
After cholera organisms are ingested, they descend to the intestinal tract where they bind to the epithelium and release their exotoxin, choleragen. This induces the epithelial cells to excrete salt. The cells then lose water which passively flows out of the cells. Fluid and electrolyte replacement is the key to treating cholera patients. V. cholerae will form small yellow colonies on this medium.