A novel multidrug resistance plasmid isolated from an Escherichia coli strain resistant to aminoglycosides

• Published in: Journal of antimicrobial chemotherapy 2012-07, Vol.67 (7), p.1635-1638
• Main Authors: Sun, Hui, Li, Shasha, Xie, Zhijing, Yang, Fangfang, Sun, Yani, Zhu, Yanli, Zhao, Xiaomin, Jiang, Shijin
• Format: Article
• Language: English
• Subjects: Amikacin; Aminoglycoside antibiotics; Aminoglycosides - pharmacology; Animals; Anti-Bacterial Agents - pharmacology; Antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Chickens; China; Circular DNA; Data processing; Deoxyribonucleic acid; Diffusion; DNA; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Drug resistance; Drug Resistance, Multiple, Bacterial; Ducks; E coli; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Gentamicin; Kanamycin; Medical sciences; Microbial Sensitivity Tests; Minimum inhibitory concentration; Molecular Sequence Data; Molecular Typing; Multidrug resistance; Neomycin; Pharmacology. Drug treatments; Plasmids; Plasmids - isolation & purification; Polymerase Chain Reaction; Polymorphism; Polymorphism, Restriction Fragment Length; Poultry Diseases - microbiology; Restriction fragment length polymorphism; Sequence Analysis, DNA; Streptomycin
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dks107

Previous studies have reported several different plasmids that confer multidrug resistance (MDR) including resistance to aminoglycosides. In this study, we investigated the aminoglycoside resistance patterns for 224 Escherichia coli isolates from diseased chickens and ducks in China, characterized a novel MDR plasmid, and collected prevalence data on similar resistance plasmids. Antibiotic susceptibilities were determined using disc diffusion and the microdilution method. The plasmid pXZ was analysed by restriction fragment length polymorphism (RFLP) with EcoRI and SalI, and sequenced. The prevalence of similar resistance plasmids was assessed by multiplex PCR and by RFLP analysis. Among the 224 E. coli isolates, 189 (84.4%) were resistant to streptomycin, 125 (55.8%) were resistant to kanamycin, 116 (51.8%) were resistant to gentamicin, 106 (47.3%) were resistant to neomycin and 98 (43.8%) were resistant to amikacin. Among the 224 E. coli isolates, 17 contained a plasmid with the MDR-encoding region of pXZ, which showed high-level resistance to aminoglycosides (MICs of gentamicin and amikacin ≥ 512 mg/L). The plasmid pXZ was digested into five fragments by EcoRI and six fragments by SalI. The plasmid pXZ was a circular DNA molecule of 76635 bp with a 51.65% guanine + cytosine content and included four resistance genes (rmtB, fosA3, bla(TEM-1) and bla(CTX-M-24)). A novel MDR plasmid, pXZ, harbouring four resistance genes (rmtB, fosA3, bla(TEM-1) and bla(CTX-M)) was identified. To our knowledge, this is the first report of an aminoglycoside resistance plasmid harbouring the fosA3 gene.