Vibrio cholerae

Vibrio cholerae

Mohammed Ameer

• Gram negative, curved, comma shaped bacilli.
• Motile by single polar flagellum.
• Non spore forming.
• Non capsulated.
• Stain with dilute carbol-fuchsin.
Microscopical Appearance:

• Most vibrios have simple growth factor requirements and grow well in alkaline pH .

• Alkaline peptone water (enriched media for vibrio).
• Thiosulfate-Citrate-Bile salt-Sucrose(TCBS)agar is the selective media for vibrio.
• NLF.
• Acid without gas is formed in Glucose ,Maltose,Manitol and sucrose fermentation .
• Facultative anaerobes
• Oxidase and catalase positive
• IMViC : +-v+

Culture Characteristics

TCBS medium is selective because
Also, contains bile salts.
High conc. of thiosulfate and citrate .
It contains sucrose.
It contains bromothymol blue.
Some species ferment sucrose & others not ferment
Sucrose fermenting Vibrio spp (V. cholerae) appears as
yellow colonies.
Sucrose non fermenting Vibrio spp (V. parahemolyticus)
appears as green colonies.

Identification of V. cholerae Growth on TCBS
Principle


Yellow colonies,
surrounded by a yellow zone

Green colonies