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. Author manuscript; available in PMC: 2013 Nov 27.
Published in final edited form as: Nat Rev Microbiol. 2009 Oct;7(10):10.1038/nrmicro2204. doi: 10.1038/nrmicro2204

Figure 1. Phylogenetic relationship of Vibrio cholerae strains.

Figure 1

On the basis of the antigenicity of the O antigen component of the outer membrane lipopolysaccharide, more than 200 serogroups (O1–O200) of Vibrio cholerae exist in aquatic environments. Only a subset of O1 and O139 serogroup strains are toxigenic (Tox+) and therefore capable of causing cholera when ingested; such strains are selected for in the host. Other strains are non-toxigenic (Tox−) and are selected against. Different O antigen types are indicated by the colour of the outer membrane and sheathed flagellum (the periplasmic space and the inner membrane are not shown). Capsules are present in a subset of strains. Different strain genotypes are indicated by the colour of the cytoplasm; note that Tox+ O1 and O139 have essentially the same genotype, with the exception of the O antigen genes.