Resumo

Introduction: Vibrio cholerae is the causative agent of cholera, an ancestral, epidemic and pandemic infection, which is a major public health concern worldwide. V. cholerae O1 classical and El Tor biotype are related to the sixty (1899 to 1923) and seventh (1960 - ....) cholera pandemics, respectively. The seventh pandemic reached Latin America (LA) in 1991 and its origin was related, immediately, to Southwest Asia, where cholera is endemic and epidemic. A second hypothesis emerged suggesting a regional environmental origin. Since the beginning of this century, the LA epidemic ended, occurring only occasional case reports. Here, we studied, from the perspective of V. cholerae genetics and genomics, the lineage of the LA cholera epidemic. Our objectives were to infer their origin and identify genomic markers that would enable its monitoring. Methodology: In order to establish the genetic relationships among V. cholerae strains isolated before, during and after the epidemic in Latin America, we used multi-locus sequence analysis (MLSA) and genetic characterization based on 355 clinical and environmental strains, from different years and geographical regions. Based on 33 complete genomes from Latin America cholera epidemics were performed the pan-genome analysis, including core-genome and unique genes identification of the Latin America cholera strains. Also, genome content profile analysis, genetic variation analysis of virulence genes and strain evolution were performed using pan-genome analysis pipeline, R scripts, BRIG software, splitTree4 and genoPlotR. Results and conclusion: The MLSA analysis, based on three genes of the core genome, revealed that the LA epidemic lineage belongs to the El Tor clade. Additionally, the genotypes of the major virulence determinants, ctxB and tcpA (accessory genome), show that the LA lineage is related with strains from the beginning of the seventh pandemic, including the canonical N16961. Considering, this large set of genomes, we confirm the prophage WASA1 as a LA lineage marker. The LA lineage is also characterized by an unique VSP-II genomic island. Interestingly, the two LA markers, WASA1 and VSP-II, which are part of its accessory genome, have similarity with genetic elements identified in Vibrio vulnificus / Vibrio parahaemolyticus and V. vulnificus / V. cholerae environmental, respectively.