title: Prevalence and Molecular Characterization ofmcr-1-Positive Salmonella Strains Recovered from Clinical Specimens in China.
abstract: The recently discovered colistin resistance element,mcr-1, adds to the list of antimicrobial resistance genes that rapidly erode the antimicrobial efficacy of not only the commonly used antibiotics but also the last-line agents of carbapenems and colistin. This study investigated the prevalence of the mobile colistin resistance determinantmcr-1inSalmonellastrains recovered from clinical settings in China and the transmission potential ofmcr-1-bearing mobile elements harbored by such isolates. Themcr-1gene was recoverable in 1.4% of clinical isolates tested, with the majority of them belonging toSalmonella entericaserotype Typhimurium. These isolates exhibited diverse pulsed-field gel electrophoresis (PFGE) profiles and high resistance to antibiotics other than colistin and particularly to cephalosporins. Plasmid analysis showed thatmcr-1was carried on a variety of plasmids with sizes ranging from ∼30 to ∼250 kb, among which there were conjugative plasmids of ∼30 kb, ∼60 kb, and ∼250 kb and nonconjugative plasmids of ∼140 kb, ∼180 kb, and ∼240 kb. Sequencing of representativemcr-1-carrying plasmids revealed that all conjugative plasmids belonged to the IncX4, IncI2, and IncHI2 types and were highly similar to the corresponding types of plasmids reported previously. Nonconjugative plasmids all belonged to the IncHI2 type, and the nontransferability of these plasmids was attributed to the loss of a region carrying partial or completetragenes. Our data revealed that, similar to the situation inEscherichia coli,mcr-1transmission inSalmonellawas accelerated by various plasmids, suggesting that transmission ofmcr-1-carrying plasmids between different species ofEnterobacteriaceaemay be a common event.
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Mingquan
authors.initials: M
authors.lastname: Cui
authors.affiliation: Shenzhen Key Laboratory for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, People's Republic of China.
authors.forename: Jinfei
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Emerging Infections Program China Office, People's Republic of China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Ruichao
authors.initials: R
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Edward Wai-Chi
authors.initials: EW
authors.lastname: Chan
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Meiyin
authors.initials: M
authors.lastname: Yan
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China wucm@cau.edu.cn xuxuebin@scdc.sh.cn sheng.chen@polyu.edu.hk.
authors.forename: Congming
authors.initials: C
authors.lastname: Wu
authors.affiliation: Microbiology Laboratory, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, People's Republic of China wucm@cau.edu.cn xuxuebin@scdc.sh.cn sheng.chen@polyu.edu.hk.
authors.forename: Xuebin
authors.initials: X
authors.lastname: Xu
authors.affiliation: Shenzhen Key Laboratory for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, People's Republic of China wucm@cau.edu.cn xuxuebin@scdc.sh.cn sheng.chen@polyu.edu.hk.|State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Sheng
authors.initials: S
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D003091:Colistin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics; D004982:Ethanolaminephosphotransferase / Q000235:genetics*; D006801:Humans; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics*; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C000614037:MCR-1 protein, E coli; D004982:Ethanolaminephosphotransferase; D003091:Colistin
keywords: IncHI2; IncI2; IncX4; Salmonella; mcr-1; plasmid; transmission