Analysis of the genetic features of the structural organization of integrative conjugative elements of <i>Vibrio cholerae</i> strains of various origins

Background: Integrative conjugative elements (ICEs) play a significant role in the dissemination of antibiotic resistance genes among Vibrio cholerae strains. However, there are currently no standardized methods for ICE typing that allow for the analysis of large genomic datasets. Aim: To conduct a comparative analysis of ICE sequences in Vibrio cholerae strains of various origins and to develop an algorithm for their typing. Materials and methods: The study utilized whole-genome sequencing data from 120 toxigenic (ctxAB+tcpA+) V. cholerae O1 El Tor strains obtained using the MiSeq platform (Illumina, USA) and MinION platform (Oxford Nanopore, UK), as well as data from NCBI databases (1,886 genomes) and the European Nucleotide Archive (441 strains). The software for ICE detection and typing was developed in Java (version 11.0.13) and is available at: http://antiplague.ru/ice-genotyper/. Results: A comparative analysis of ICE elements in toxigenic V. cholerae strains was performed. An ICE typing algorithm based on gene composition was proposed. Analysis of the V. cholerae genome collection revealed three previously undescribed ICE elements, designated ICEVchRus1, ICEVchHai3, and ICEVchLaos. Conclusions: The study identified three previously undescribed ICE elements and mapped their distribution across Russia and other regions of the world. It was established that during the cholera outbreak in Dagestan in 1994, strains containing ICEVchBan11 and ICEVchBan9 were circulating simultaneously.