Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh, 13736, Egypt.
Internal Medicine/Adult Endocrinology/Bariatric Medicine, Adiriyah Hospital, MoH, Riyadh, Saudi Arabia.
BMC Vet Res. 2022 Jul 29;18(1):293. doi: 10.1186/s12917-022-03389-z.
Staphylococcus aureus is a common mastitis pathogen in dairy cows, and methicillin-resistant S. aureus (MRSA) has been found in dairy farms all over the world. The study carried out on bovines from three governorates in Egypt, with the goal of determining the prevalence of MRSA in positive milk samples of subclinical mastitis, performing an antibiotic susceptibility test against MRSA isolates and determining the risk factors associated with MRSA. A total of 350 quarter milk samples (n = 200 mixed breed cow; n = 150 water buffalo) were collected and examined for subclinical mastitis using the California mastitis test (CMT) before being exposed to standard microbiological procedures for S. aureus isolation. The disc diffusion method was used to phenotypically analyse the positive S. aureus isolates for MRSA, which was verified by a PCR assay targeting the mecA gene. According to the findings of the study, 41.4% (145/350) milk samples were positive based on CMT, while 35.7% (125/350) of positive samples identified as MRSA based on PCR assay. However, the obtained results revealed non-significant disparity between cattle and buffalo and all predicted risk factors were strongly associated with prevalence of subclinical mastitis. The in-vitro antibiotic susceptibility test revealed that cefoxitin was completely resistant, whereas linezolid, ciprofloxacin, and trimethoprim + sulphamethoxazole were sensitive against the MRSA isolates. The relevance of S. aureus to public health, as well as the development of resistance to antibiotics like methicillin, needs ongoing testing of antimicrobial medications against MRSA isolates.
金黄色葡萄球菌是奶牛乳腺炎的常见病原体，耐甲氧西林金黄色葡萄球菌（MRSA）已在世界各地的奶牛场中发现。本研究在埃及三个省的牛群中进行，旨在确定隐性乳腺炎阳性牛奶样本中 MRSA 的流行率，对 MRSA 分离株进行抗生素药敏试验，并确定与 MRSA 相关的风险因素。共采集 350 份四分奶样（n=200 杂种牛；n=150 水牛），使用加利福尼亚乳房炎试验（CMT）进行隐性乳腺炎检测，然后进行标准微生物程序分离金黄色葡萄球菌。采用纸片扩散法对阳性金黄色葡萄球菌分离株进行 MRSA 表型分析，并用针对 mecA 基因的 PCR 检测进行验证。根据研究结果，根据 CMT，41.4%（145/350）的奶样呈阳性，而根据 PCR 检测，35.7%（125/350）的阳性样本被鉴定为 MRSA。然而，牛和水牛之间的结果没有显著差异，所有预测的风险因素都与隐性乳腺炎的流行密切相关。体外抗生素药敏试验显示头孢西丁完全耐药，而利奈唑胺、环丙沙星和复方磺胺甲噁唑对 MRSA 分离株敏感。金黄色葡萄球菌对公共卫生的相关性以及对甲氧西林等抗生素的耐药性发展需要对 MRSA 分离株进行抗菌药物的持续测试。
