title: Variations in SXT elements in epidemic Vibrio cholerae O1 El Tor strains in China.
abstract: Vibrio cholerae O1 El Tor biotype strains are responsible for three multiyear epidemics of cholera in China during the seventh ongoing pandemic. The presence of the integrative conjugative element SXT is strongly correlated with resistance to nalidixic acid, tetracycline, and trimethoprim-sulfamethoxazole in these strains. Here, we sequenced the conserved genes of the SXT element, including eex, setR, and int, from 59 V. cholerae O1 El Tor strains and extracted and assembled the intact SXT sequences from the 11 genome sequenced strains. These elements had characteristics distinct from those of previously reported integrative conjugative elements (ICEs). They could be clearly divided into two types based on the clustering of conserved genes and gene structures of the elements, showing their possibly independent derivation and evolution. These two types were present before and after 2005, respectively, demonstrating the type substitution that occurred in 2005. Four to six antibiotic-resistant genes were found on the SXT elements, including genes resistant to tetracycline, trimethoprim-sulfamethoxazole, and multiple drugs. In summary, our findings demonstrated the roles of the SXT element in the emergence of multidrug resistance in epidemic O1 El Tor V. cholerae strains in China.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing 102206, P. R. China.|Collaborative Innovation Centre of Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Ruibai
authors.initials: R
authors.lastname: Wang
authors.affiliation: Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, Beijing 100071, P. R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Yu
authors.affiliation: Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, Beijing 100071, P. R. China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Yue
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing 102206, P. R. China.|Collaborative Innovation Centre of Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D058872:Epidemics; D019143:Evolution, Molecular; D014644:Genetic Variation; D006801:Humans; D020071:Interspersed Repetitive Sequences; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents