Evidence of Environmental Evolution of Toxigenic Vibrio cholerae in Aquatic Reservoirs. Vibrio cholerae

Persistent aquatic environmental reservoirs for Vibrio cholerae are present in Asia; however, their existence in other parts of the world remains controversial. The single-source introduction of V. cholerae O1 in Haiti, in the aftermath of the 2010 earthquake, provided a unique opportunity to determine the role aquatic reservoirs play in seasonal outbreaks. Whole genome sequence Bayesian phylogeography showed robust evidence of V. cholerae O1 persistence-driven evolution in the aquatic environment through the establishment of reservoirs during lull periods of the Haitian epidemic. Novel lineages emerged in the environment from sequential population bottlenecks, characterized by mutations in genes potentially involved in adaptive response. The data highlight the importance of the aquatic environment in overall persistence and evolution of this global pathogen.