title: Multiple transmissible genes encoding fluoroquinolone and third-generation cephalosporin resistance co-located in non-typhoidal Salmonella isolated from food-producing animals in China.
abstract: The aim of this study was to identify genes conferring resistance to fluoroquinolones and extended-spectrum β-lactams in non-typhoidal Salmonella (NTS) from food-producing animals in China. In total, 31 non-duplicate NTS were obtained from food-producing animals that were sick. Isolates were identified and serotyped and the genetic relatedness of the isolates was determined by pulsed-field gel electrophoresis of XbaI-digested chromosomal DNA. Antimicrobial susceptibility was determined using Clinical and Laboratory Standards Institute methodology. The presence of extended-spectrum β-lactamase (ESBL) and fluoroquinolone resistance genes was established by PCR and sequencing. Genes encoded on transmissible elements were identified by conjugation and transformation. Plasmids were typed by PCR-based replicon typing. The occurrence and diversity of numerous different transmissible genes conferring fluoroquinolone resistance [qnrA, qnrD, oqxA and aac(6')-Ib-cr] and ESBLs (CTX-M-27 and CTX-M-14), and which co-resided in different isolates and serovars of Salmonella, were much higher than in European countries. Furthermore, different plasmids encoded fluoroquinolone resistance (ca. 6 kb) and β-lactam resistance (ca. 63 kb) and these co-resided in isolates with mutations in topoisomerase genes (gyrA and parC) giving very resistant Salmonella. The presence of multidrug-resistant bacteria in food-producing animals in countries that export foodstuffs suggests that global transfer of antibiotic resistances from country to country on food is possible.
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Jiang
authors.affiliation: China Institute of Veterinary Drug Control, Beijing 100081, China.
authors.forename: Li
authors.initials: L
authors.lastname: Song
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Yan-Na
authors.initials: YN
authors.lastname: Ren
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Antimicrobials Research Group, School of Immunity and Infection, Institute of Microbiology of Infection and College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Webber
authors.affiliation: Antimicrobials Research Group, School of Immunity and Infection, Institute of Microbiology of Infection and College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: David O
authors.initials: DO
authors.lastname: Ogbolu
authors.affiliation: College of Veterinary Medicine, National Reference Laboratory of Veterinary Drug Residues, South China Agricultural University (SCAU), Guangzhou 510642, China.
authors.forename: Zhen-Ling
authors.initials: ZL
authors.lastname: Zeng
authors.affiliation: Antimicrobials Research Group, School of Immunity and Infection, Institute of Microbiology of Infection and College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK. Electronic address: l.j.v.piddock@bham.ac.uk.
authors.forename: Laura J V
authors.initials: LJ
authors.lastname: Piddock
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D002511:Cephalosporins / Q000494:pharmacology*; D002681:China; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D024841:Fluoroquinolones / Q000494:pharmacology*; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D058889:Molecular Typing; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012475:Salmonella / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012703:Serotyping
chemical_list: D002511:Cephalosporins; D004269:DNA, Bacterial; D024841:Fluoroquinolones
keywords: ESBL; Fluoroquinolone; Plasmid; Salmonella