SXT-related integrating conjugative element in New World Vibrio cholerae

Abstract

SXT-related integrating conjugative elements (ICEs) became prevalent in Asian Vibrio cholerae populations after V. cholerae O139 emerged. Here, we describe an SXT-related ICE, ICEVchMex1, in a Mexican environmental V. cholerae isolate. Identification of ICEVchMex1 represents the first description of an SXT-related ICE in the Western Hemisphere. The significant differences between the SXT and ICEVchMex1 genomes suggest that these ICEs have evolved independently.

FIG. 1.

Schematic linear representation of the SXT^MO10 and R391 conserved set of genes and of the insertions specific to ICEVchMex1. The black line represents the set of genes conserved in SXT^MO10 and R391. The three hotspots for the insertion of additional DNA are indicated with stars. Gray arrows represent the conserved genes in SXT^MO10, R391, and ICEVchMex1. The scale for the insertions is 1 cm per kb. The genes that are specific to ICEVchMex1 are shown as white arrows. SXT^MO10 genes that are not present in ICEVchMex1 are shown as black arrows. The location of the antibiotic gene cluster in SXT^MO10 is shown as a hatched box (not to scale). The locations of primers used for analysis (Table 2) are shown as arrowheads. ΔIS, remnant of insertion sequence.