RESUMO
The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that Vibrio cholerae, the etiologic agent of cholera, remains a scourge. We report the isolation of both V. cholerae O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of V. cholerae coexisted in Haiti early in the epidemic. As non-O1/O139 V. cholerae was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with V. cholerae O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian V. cholerae O1 and V. cholerae non-O1/O139 strains. A total of 47 V. cholerae O1 and 29 V. cholerae non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of V. cholerae isolated in concurrent epidemics outside Haiti and 27 V. cholerae genomes available in the public database demonstrated substantial diversity of V. cholerae and ongoing flux within its genome.
Assuntos
Cólera/epidemiologia , Cólera/microbiologia , Surtos de Doenças , Variação Genética , Genoma Bacteriano/genética , Vibrio cholerae/genética , Proteínas de Bactérias/genética , Sequência de Bases , Haiti/epidemiologia , Humanos , Anotação de Sequência Molecular , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal , Análise de Sequência de DNA , Especificidade da Espécie , Sequências de Repetição em Tandem/genéticaRESUMO
This report describes Vibrio seventh pandemic island II (VSP-II) and three novel variants revealed by comparative genomics of 23 Vibrio cholerae strains and their presence among a large and diverse collection of V. cholerae isolates. Three VSP-II variants were reported previously and our results demonstrate the presence of three novel VSP-II in clinical and environmental V. cholerae marked by major deletions and genetic rearrangements. A new VSP-II cluster was found in the seventh pandemic V. cholerae O1 El Tor strain CIRS101, which is dominant (95%) among the recent (2004-2007) seven pandemic V. cholerae O1 El Tor isolates from two endemic sites, but was not found in older strains from the same region. Two other variants were found in V. cholerae TMA21 and RC385, two environmental strains from coastal Brazil and the Chesapeake Bay, respectively, the latter being prevalent among environmental V. cholerae non-O1/non-O139 and Vibrio mimicus. The results of this study indicate that the VSP-II island has undergone significant rearrangement through a complex evolutionary pathway in V. cholerae. Interestingly, one of the new VSP-II revealed the presence of 'old' and 'new' V. cholerae O1 El Tor pandemic clones circulating in some of the areas where cholera is endemic.