Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Shandong Centre for Disease Control and Prevention, Jinan, Shandong, China.
J Antimicrob Chemother. 2018 May 1;73(5):1194-1200. doi: 10.1093/jac/dky009.
To investigate the presence and molecular characteristics of oxazolidinone resistance genes cfr and optrA in staphylococci from household animals in rural China.
Various samples were collected from household animals in 12 rural villages. Staphylococcal isolates showing florfenicol MICs ≥10 mg/L were identified and screened for the presence of cfr and/or optrA. PCR-positive isolates were characterized by antimicrobial susceptibility testing, S1 nuclease PFGE and Southern blotting. WGS data were analysed to identify the core-genome phylogenetic profile of each isolate as well as the genetic environment of cfr and/or optrA.
Nine optrA-positive (seven Staphylococcus sciuri and two Staphylococcus simulans) and 10 cfr-positive staphylococci were identified from eight and five villages, respectively. The gene optrA was chromosomally encoded in all nine isolates, whereas cfr was located on a plasmid in one S. sciuri and three Staphylococcus saprophyticus and in the chromosomal DNA of single Staphylococcus cohnii and Staphylococcus lentus isolates and two S. sciuri isolates. The remaining two cfr-carrying Staphylococcus haemolyticus isolates were indistinguishable by PFGE. Most optrA- or cfr-carrying staphylococci also harboured phenicol, tetracycline and/or macrolide-lincosamide-streptogramin B resistance genes. Genetic environment analysis showed that, for the first time, optrA was associated with transposon Tn6261, while cfr was adjacent to both a tnp (transposase) gene and a Tn558 transposon.
The current study reveals for the first time the wide distribution of oxazolidinone resistance genes optrA and cfr in household animals in rural areas of China and is the first identification of optrA in S. simulans isolates.
调查中国农村家庭动物分离的葡萄球菌中恶唑烷酮类耐药基因 cfr 和 optrA 的存在情况及其分子特征。
从 12 个农村村庄的各种样本中采集葡萄球菌分离株。对氟苯尼考 MIC≥10mg/L 的分离株进行鉴定和筛选，以确定 cfr 和/或 optrA 的存在。对 PCR 阳性分离株进行药敏试验、S1 核酸酶 PFGE 和 Southern 印迹分析。对 WGS 数据进行分析，以确定每个分离株的核心基因组系统发育谱以及 cfr 和/或 optrA 的遗传环境。
从 8 个和 5 个村庄中分别鉴定出 9 株 optrA 阳性（7 株松鼠葡萄球菌和 2 株人葡萄球菌）和 10 株 cfr 阳性葡萄球菌。所有 9 株分离株的 optrA 基因均位于染色体上，而 cfr 则位于 1 株松鼠葡萄球菌和 3 株腐生葡萄球菌的质粒上，以及 1 株 S. cohnii 和 1 株 S. lentus 分离株的染色体 DNA 上，还有 2 株松鼠葡萄球菌分离株的 cfr 位于染色体上。其余 2 株携带 cfr 的解血链球菌分离株经 PFGE 无法区分。大多数携带 optrA 或 cfr 的葡萄球菌还携带青霉素、四环素和/或大环内酯类-林可酰胺类-链阳菌素 B 耐药基因。遗传环境分析表明，optrA 首次与转座子 Tn6261 相关，而 cfr 则与转座酶基因 tnp 和 Tn558 转座子相邻。
本研究首次揭示了中国农村地区家庭动物中广泛存在的恶唑烷酮类耐药基因 optrA 和 cfr，也是首次在 S. simulans 分离株中发现 optrA。
