title: Isolation and molecular characterization of multidrug-resistant Enterobacteriaceae strains from pork and environmental samples in Xiamen, China.
abstract: This study was conducted to investigate the prevalence and molecular characterization of multidrug-resistant (MDR) Enterobacteriaceae isolated from swine meat and the breeding environment. A total of 102 MDR Enterobacteriaceae strains belonging to five genera were obtained from 210 samples collected from a large-scale swine farm from March 2012 to June 2013 in Xiamen, People's Republic of China. Among these MDR isolates, Escherichia coli strains were found most frequently in both meat and environmental samples, followed by Citrobacter spp., Klebsiella spp., and Shigella spp. The neighbor-joining phylogenetic tree indicated that 70.3 % of Escherichia and 50 % of Citrobacter isolates from meat samples shared 100 % homology with relevant isolates from environmental samples. Resistance was most frequently observed to sulfonamide, trimethoprim, aminoglycoside, chloramphenicol, β-lactam, and tetracycline. Close correlation was noted between antibiotic resistance phenotype and the genes responsible for resistance to sulfonamide (sulI), trimethoprim (dhfrI), aminoglycoside (aadA, aac(3)-I, aphA-1, and aac(3)-IV), chloramphenicol (catI and cmlA), β-lactam (blaSHV, blaOXA, and blaTEM), florfenicol (floR), and tetracycline (tet(A) and tet(B)), which were widely distributed with prevalences of 72.5, 6.9, 62.7, 14.7, 78.4, 11.8, 25.5, 42.2, 12.7, 14.7, 39.2, 87.2, 68.6, and 34.3 % , respectively. Class 1 integrons carrying aadA22, dfrA17-aadA5, or dfrA12-aadA2 cassette arrays were commonly found in isolates from all samples. The gene cassette aac(6')-Ib-cr-arr-3-dfrA27-aadA16 was first found in an Enterobacter amnigenus isolate. Conjugation experiments revealed the plasmid-mediated transfer of class 1 integrons. Our results indicate that swine meat and the farming environment can be sources of antibiotic-resistant bacteria, which could be potentially transmitted to humans via the meat products industry chain.
authors.affiliation: College of Light Industry and Food Technology, South China University of Technology, Guangzhou 510640, People's Republic of China; State Key Laboratory of Food Safety Technology for Meat Products and Synergetic Innovation Center of Food Safety and Nutrition, Xiamen Yinxiang Group Co., Ltd., Xiamen 361100, People's Republic of China.
authors.forename: Zongbao
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Safety Technology for Meat Products and Synergetic Innovation Center of Food Safety and Nutrition, Xiamen Yinxiang Group Co., Ltd., Xiamen 361100, People's Republic of China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Light Industry and Food Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Yan
authors.affiliation: Food Safety Key Lab of Liaoning Province, Bohai University, Jinzhou 121013, People's Republic of China. lijr6491@yahoo.com.cn.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Light Industry and Food Technology, South China University of Technology, Guangzhou 510640, People's Republic of China; State Key Laboratory of Food Safety Technology for Meat Products and Synergetic Innovation Center of Food Safety and Nutrition, Xiamen Yinxiang Group Co., Ltd., Xiamen 361100, People's Republic of China. leishi88@hotmail.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D032023:Integrons / Q000235:genetics; D008460:Meat / Q000382:microbiology*; D010802:Phylogeny; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents