Analysis of Vibrio seventh pandemic island II and novel genomic islands in relation to attachment sequences among a wide variety of Vibrio cholerae strains.

ABSTRACT: Vibrio cholerae O1 El Tor, the pathogen responsible for the current cholera pandemic, became pathogenic by acquiring virulent factors including Vibrio seventh pandemic islands (VSP)-I and -II. Diversity of VSP-II is well recognized; however, studies addressing attachment sequence left (attL) sequences of VSP-II are few. In this report, a wide variety of V. cholerae strains were analyzed for the structure and distribution of VSP-II in relation to their attachment sequences. Of 188?V. cholerae strains analyzed, 81% (153/188) strains carried VSP-II; of these, typical VSP-II, and a short variant was found in 36% (55/153), and 63% (96/153), respectively. A novel VSP-II was found in two V. cholerae non-O1/non-O139 strains. In addition to the typical 14-bp attL, six new attL-like sequences were identified. The 14-bp attL was associated with VSP-II in 91% (139/153), whereas the remaining six types were found in 9.2% (14/153) of V. cholerae strains. Of note, six distinct types of the attL-like sequence were found in the seventh pandemic wave 1 strains; however, only one or two types were found in the wave 2 or 3 strains. Interestingly, 86% (24/28) of V. cholerae seventh pandemic strains harboring a 13-bp attL-like sequence were devoid of VSP-II. Six novel genomic islands using two unique insertion sites to those of VSP-II were identified in 11?V. cholerae strains in this study. Four of those shared similar gene clusters with VSP-II, except integrase gene.

SUBMITTER: Nguyen TH 

PROVIDER: S-EPMC5900727 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature