Vibrio cholera

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Classification

Bacteria; Proteobacteria; Gammaproteobacteria; Vibrionales; Vibrionaceae [Others may be used. Use NCBI link to find]

Species

NCBI: Taxonomy

Vibrio cholerae

Description and Significance

V. cholerae is a gram-negative, curved rod-shaped, facultative anaerobe. It is highly motile by a single polar flagellum, and capable of both respiratory and fermentative metabolism. It is oxidase positive. Of all the Vibrios , cholera is the most significantly important to humans. [1]

Genome Structure

Vibrio cholera contains a 4.0Mbp genome, consisting of two circular chromosomes. There are a predicted 3,885 total genes.[3]

Cell Structure, Metabolism and Life Cycle

Curved rod-shaped, singular polar flagellum. In the lab, optimal growth is in media containing an inorganic nitrogen source and a utilizable carbon source. Glucose is used as the carbon and energy source. In adequate media, the generation time is less than 30 min. O2 is the universal terminal electron acceptor for metabolism. Vibrio cholera are facultative anaerobes, preferring oxygenated environments to anaerobic. Optimal temperature for growth is 37degC, with growth possible between 10-43degC. The optimal pH is 7.6, growth possible at pH 5.0-9.6. [5] Biofilm formation is dependent on the production of an exopolysaccharide (EPS). The free-swimming V. cholera adhere to a solid surface, inducing expression of EPS. The bacteria then lose their flagella as the biofilm forms. [2]

Ecology and Pathogenesis

Vibrio cholera is often found in the aquatic environment and is part of the normal flora of brackish water and estuaries. Vibrio cholera can infect the human small intestine. In addition, during interepidemic periods , Vibrio cholera can adhere to copepods. This provides protection and a nutrient source for the microbe. The attachment of vibrio cholera is significant, because other bacteria including pseudumonas, and E. coli did not adhere to copepods. [4]

The only known host for V. cholera is the human intestine. Pathogenicity is caused by serotypes O1 and the Gulf Coast El Tor strains. The disease is caused by production of the CT toxin, choleragen or the cholera toxin. Classical O1 V. cholera and the Gulf Coast El Tor produce CT-1. Most other El Tor strains and O139 produce CT-2. These toxins, when colonized in the small intestines, cause diarrhea, which in some cases can lead to dehydration, anuria, acidosis, and shock. [6]

References

1. Vibrio cholerae and Asiatic Cholera 2. Heithoff, Mahan. Vibrio cholerae Biofilms: Stuck between a Rock and a Hard Place. 2004 3.Faruque, S, Nair, G. Vibrio cholerae: Genomics and Molecular Biology. Caister Academic Press. 2008 4. Rawlings, Ruiz, Colwell. Associations of Vibrio cholera O1 El Tora and 0139 Bengal with the Copepods Acartia tonsa and Eurytemora addinis 5. [www.nzfsa.govt.nz/science/data-sheets/vibrio-cholerae.pdf Microbial Pathogens Data Sheet: VIBRIO CHOLERAE] 6. Vibrio cholerae

Author

Page authored by Rachel Talaski and Guy Thompson, student of Prof. Jay Lennon at Michigan State University.