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Back to Bacteria Index
Vibrio cholerae
Morphology
Vibrio cholerae is a rod-shaped bacterium that causes cholera in
humans.
It and other species of the genus Vibrio belong to the gamma
subdivision of the proteobacteria. There are two dominant strains,
classic and El Tor. are in the O1 serogroup and both contain Inaba,
Ogawa and Hikojima serotypes
It colonizes the gut, where it adheres to villous absorptive cells via
filaments, and secretes a toxin, causing massive fluid and electrolyte
loss by diarrhea.
Cultural characteristics
They are highly aerobic and grow on simple media. Growth is favoured
by alkaline pH. They grow to form a pellicle on alkaline peptone
within 8 hours. On TCBS medium they give yellow colonies.
Biochemical activities
They ferment glucose, maltose, mannite and sucrose with the production
of acid only. They give a positive cholera-red reaction.
Pathogenesis
Vibrio cholera produces a heat labile enterotoxin which consists of
subunits A and B. Subunit B promotes entry of subunit A into the cell.
Subunit A results in prolonged hypersecretion of water and
electrolytes leading to severe diarrhea (cholera) in which more than
20 litres of diarrhea a day can lead to dehydration, acidosis and
shock.
Diseases caused by Vibrio cholera
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