College of Agriculture, Ningxia University, Ningxia 750021, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
J Glob Antimicrob Resist. 2021 Jun;25:232-237. doi: 10.1016/j.jgar.2021.03.021. Epub 2021 Apr 15.
The aim of this study was to explore the antimicrobial resistance, virulence genes and molecular characteristics of Staphylococcus aureus from bovine mastitis cases.
A total of 125 non-duplicate S. aureus isolates from bovine mastitis cases in Ningxia, China, were characterised by antimicrobial susceptibility and molecular testing to determine the antimicrobial resistance, virulence genes and molecular characteristics.
All methicillin-resistant S. aureus (MRSA) isolates were resistant to ampicillin, oxacillin, ceftiofur, erythromycin, gentamicin and clindamycin, with resistance to nine different categories of antibiotics observed amongst the MRSA isolates. Of the methicillin-susceptible S. aureus (MSSA) isolates, 62.1% were resistant to ampicillin and sulfisoxazole. Nine clonal complexes (CCs) and 16 spa types were identified by multilocus sequence typing (MLST) and spa typing. The dominant CCs were CC97 (51.2%) and CC50 (30.4%), while t224 (30.4%), t518 (20.0%) and t359 (16.8%) were the most common spa types. A relatively high proportion (27.2%) of the S. aureus isolates belonged to ST4053, a novel sequence type identified in this study. In addition, two CC30 MSSA isolates and two CC59 MRSA isolates were positive for Panton-Valentine leukocidin, while one CC239 MRSA isolate and three CC5 MSSA isolates were positive for TSST-1. All MRSA isolates carried the immune evasion cluster (IEC) genes, including scn (100%; 9/9) and sak (100%; 9/9), which were classified into type E.
Our study indicates severe antibiotic resistance and complicated molecular characterisation of S. aureus causing bovine mastitis. Additional studies should be conducted to monitor infection and transmission of S. aureus.
本研究旨在探讨奶牛乳腺炎分离的金黄色葡萄球菌的抗菌药物耐药性、毒力基因和分子特征。
对中国宁夏地区 125 株非重复金黄色葡萄球菌进行抗菌药物敏感性和分子检测，以确定其抗菌药物耐药性、毒力基因和分子特征。
所有耐甲氧西林金黄色葡萄球菌（MRSA）分离株均对氨苄西林、苯唑西林、头孢噻呋、红霉素、庆大霉素和克林霉素耐药，MRSA 分离株对 9 种不同类别的抗生素耐药。甲氧西林敏感金黄色葡萄球菌（MSSA）分离株中，62.1%对氨苄西林和磺胺异噁唑耐药。通过多位点序列分型（MLST）和 spa 分型鉴定了 9 个克隆复合体（CC）和 16 个 spa 型。优势 CC 为 CC97（51.2%）和 CC50（30.4%），而 t224（30.4%）、t518（20.0%）和 t359（16.8%）是最常见的 spa 型。本研究新鉴定的 ST4053 序列型占金黄色葡萄球菌分离株的比例相对较高（27.2%）。此外，2 株 CC30 MSSA 分离株和 2 株 CC59 MRSA 分离株携带杀白细胞素 Panton-Valentine（PVL），1 株 CC239 MRSA 分离株和 3 株 CC5 MSSA 分离株携带毒性休克综合征毒素-1（TSST-1）。所有 MRSA 分离株均携带免疫逃逸簇（IEC）基因，包括 scn（100%；9/9）和 sak（100%；9/9），均归类为 E 型。
本研究表明奶牛乳腺炎金黄色葡萄球菌存在严重的抗生素耐药性和复杂的分子特征。应开展进一步研究以监测金黄色葡萄球菌的感染和传播。
