title: Characterization of a transferable bcrABC and cadAC genes-harboring plasmid in Listeria monocytogenes strain isolated from food products of animal origin.
abstract: In this study, we characterized a bcrABC cassette and its genetic environment harbored by a plasmid in Listeria monocytogenes (L. monocytogenes) 11GZL18, a strain isolated from raw meat in 2011. The bcrABC cassette and its genetic environment were characterized, with a total of 33,727 nt nucleotide sequence obtained. The nucleotide sequences of the bcrABC cassette in strain 11GZL18 exhibited 100% identity to that on plasmid pLM80, which is harbored by L. monocytogenes strain H7550 and H7858, and the neighboring 21,678 nt nucleotide sequence of bcrABC cassette showed 99% identity with plasmid pLM80. The plasmid curing experiment demonstrated the role of the plasmid in conferring benzalkonium chloride (BC) and cadmium (Cd) tolerance in this strain. The bcrABC cassette and cadAC genes from the L. monocytogenes 11GZL18 were harbored by plasmid, functional and transmissible, and led to the acquired tolerance in Gram-negative Escherichia coli (E. coli) DH5α by chemical and natural transformation. Besides, the efflux pump activity that is conferring tolerance to BC and Cd was observed in strain 11GZL18, while not in a plasmid-cured strain 11GZL18-C, confirming that efflux pumps play a role in plasmid-mediated tolerance to BC and Cd in L. monocytogenes 11GZL18. In this study we characterized the genetic organization of a novel BC and Cd tolerance determinants-harboring plasmid in a L. monocytogenes strain isolated from raw meat of animal origin, and demonstrated the potential horizontal transferability of this bcrABC cassette-harboring plasmid to E. coli. The findings will further improve our understanding of the adaptations of this organism to disinfectants such as BC and may contribute to elucidating possible dissemination of BC tolerance in foodborne L. monocytogenes.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China.
authors.forename: Dongyang
authors.initials: D
authors.lastname: Xu
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Nie
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China.
authors.forename: Wenyan
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China; Graduate School of Life and Environment Sciences, Osaka Prefecture University, Izumisano, Osaka 598-8531, Japan.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China. Electronic address: yanhe@scut.edu.cn.
authors.forename: He
authors.initials: H
authors.lastname: Yan
mesh_terms: D001483:Base Sequence; D001548:Benzalkonium Compounds / Q000494:pharmacology*; D002104:Cadmium / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000187:drug effects / Q000235:genetics*
chemical_list: D001548:Benzalkonium Compounds; D004202:Disinfectants; D002104:Cadmium
keywords: BcrABC cassette; Benzalkonium chloride; Cadmium; Listeria monocytogenes; Tolerance