MRSA infection and colonization have been reported in both companion and food-chain animals, highlighting MRSA as an important veterinary and zoonotic pathogen. Another mec allele, the mecC gene, also confers beta-lactam resistance in Staphylococcus aureus and shows 69% nucleotide identity to mecA. The main aim of this study was to investigate the genotypic and clonal profile of methicillin-resistant S. aureus (MRSA) from cows with mastitis in dairy herds. Thirty-five samples suggestive of bovine subclinical mastitis were evaluated, and S. aureus were detected in all of them using both phenotypic and molecular approaches. According to the multilocus sequence typing (MLST), the S. aureus isolates were assigned in five different STs, 21 (60%) showed ST 742, 6 (17%) ST97, 4 (11%) ST1, 2 (6%) ST30, and 2 (6%) ST126. The presence of mecA was not observed in any of these isolates whereas mecC was detected in nine of them (9/35; 26%). The Panton-Valentine leukocidin (PVL) genes were detected in a total of 4 isolates. Among the 35 isolates analyzed, 26 showed resistance to penicillin. Changes in the S. aureus epidemiology due to the detection of MRSA in milk samples from cows presenting with bovine subclinical mastitis may have consequences for public health in Brazil, challenging the empirical therapy and animal management, with potential medical and social outcomes. To the best of our knowledge, this is the first report describing mecC MRSA in Southeastern Brazil.

中文翻译：

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巴西东南部乳腺炎奶牛牛奶样本中携带mecC基因的耐甲氧西林金黄色葡萄球菌的首次报告

MRSA 感染和定植在伴侣动物和食物链动物中都有报道，突出 MRSA 作为重要的兽医和人畜共患病原体。另一个 mec 等位基因 mecC 基因也赋予金黄色葡萄球菌 β-内酰胺抗性，并显示出与 mecA 69% 的核苷酸同一性。本研究的主要目的是调查奶牛乳腺炎奶牛的耐甲氧西林金黄色葡萄球菌 (MRSA) 的基因型和克隆特征。对 35 个提示牛亚临床乳腺炎的样本进行了评估，并使用表型和分子方法在所有样本中检测到了金黄色葡萄球菌。根据多位点序列分型 (MLST)，金黄色葡萄球菌分离株被分配到 5 个不同的 ST 中，21 (60%) 显示 ST 742、6 (17%) ST97、4 (11%) ST1、2 (6%) ST30 和 2 (6%) ST126。在这些分离株中的任何一个中都没有观察到 mecA 的存在，而在其中的九个中检测到了 mecC（9/35；26%）。Panton-Valentine leukocidin (PVL) 基因在总共 4 个分离株中被检测到。在分析的 35 个分离株中，26 个显示出对青霉素的耐药性。由于在出现牛亚临床乳腺炎的奶牛的牛奶样本中检测到 MRSA，金黄色葡萄球菌流行病学的变化可能对巴西的公共卫生产生影响，挑战经验疗法和动物管理，并带来潜在的医疗和社会后果。据我们所知，这是第一份描述巴西东南部 mecC MRSA 的报告。26 对青霉素表现出耐药性。由于在出现牛亚临床乳腺炎的奶牛的牛奶样本中检测到 MRSA，金黄色葡萄球菌流行病学的变化可能对巴西的公共卫生产生影响，挑战经验疗法和动物管理，并带来潜在的医疗和社会后果。据我们所知，这是第一份描述巴西东南部 mecC MRSA 的报告。26 对青霉素表现出耐药性。由于在出现牛亚临床乳腺炎的奶牛的牛奶样本中检测到 MRSA，金黄色葡萄球菌流行病学的变化可能对巴西的公共卫生产生影响，挑战经验疗法和动物管理，并带来潜在的医疗和社会后果。据我们所知，这是第一份描述巴西东南部 mecC MRSA 的报告。