Institute of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic.
Equine Clinic, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic.
J Antimicrob Chemother. 2024 Nov 4;79(11):2901-2905. doi: 10.1093/jac/dkae303.
We performed a retrospective analysis of MRSA isolates collected at the university equine clinic including clinical isolates from 2008 to 2021 and screening environmental, equine and personnel isolates from 2016.
Screening and clinical samples were cultured on Brilliance MRSA 2 and Columbia agar (Oxoid), respectively, with enrichment for environmental samples. Antimicrobial susceptibility was assessed by disc diffusion. All the isolates were characterized by spa typing. Eighteen selected isolates were subjected to WGS with subsequent wgMLST clonal analysis.
Among 75 MRSA isolates, five spa types were identified, the majority (n = 67; 89.33%) was t011. All isolates were resistant to cefoxitin and ampicillin and carried the mecA gene. In addition, the isolates were resistant to tetracycline (n = 74; 98.67%), gentamicin (n = 70; 93.33%), enrofloxacin (n = 54; 72.00%), sulfamethoxazole-trimethoprim (n = 5; 6.67%) and lincomycin (n = 3; 4.00%) with corresponding genetic markers for the resistance detected in the sequenced isolates. All 18 sequenced isolates belonged to ST398, 16 carried SCCmec type IVa and two carried SCCmec type Vc (5C2&5). Further, isolates carried aur, hlgA, hlgB and hlgC virulence genes, and five isolates carried sak and scn genes, which are part of the immune evasion cluster. Close genetic relatedness was found between isolates from the staff of the clinic and clinical samples of horses.
Repeated introduction and long-term persistence of the equine LA-MRSA subclone (ST398-MRSA-IVa/Vc(5C2&5), t011) among the infected horses at the equine clinic with the colonization of personnel, and the environment contamination that might contribute to transmission were observed.
我们对大学马诊所采集的耐甲氧西林金黄色葡萄球菌（MRSA）分离株进行了回顾性分析，包括 2008 年至 2021 年的临床分离株和 2016 年的环境、马和人员筛查分离株。
对筛查和临床样本分别在 Brilliance MRSA 2 和哥伦比亚琼脂（Oxoid）上进行培养，对环境样本进行富集。通过纸片扩散法评估抗菌药物敏感性。所有分离株均通过 spa 分型进行特征描述。对 18 株选定的分离株进行 WGS 检测，随后进行 wgMLST 克隆分析。
在 75 株 MRSA 分离株中，鉴定出 5 种 spa 型，其中大多数（n=67；89.33%）为 t011。所有分离株均对头孢西丁和氨苄西林耐药，并携带 mecA 基因。此外，这些分离株对四环素（n=74；98.67%）、庆大霉素（n=70；93.33%）、恩诺沙星（n=54；72.00%）、磺胺甲恶唑-甲氧苄啶（n=5；6.67%）和林可霉素（n=3；4.00%）耐药，在测序分离株中检测到相应的耐药基因标记。18 株测序分离株均属于 ST398，16 株携带 SCCmec 型 IVa，2 株携带 SCCmec 型 Vc（5C2&5）。此外，分离株携带 aur、hlgA、hlgB 和 hlgC 毒力基因，5 株分离株携带 sak 和 scn 基因，这些基因属于免疫逃避簇的一部分。在马诊所的工作人员和马的临床样本中发现了密切的遗传相关性。
在马诊所的感染马中，耐甲氧西林金黄色葡萄球菌（LA-MRSA）亚克隆（ST398-MRSA-IVa/Vc（5C2&5），t011）反复引入并长期存在，人员定植和环境污染可能有助于传播。
