The population of methicillin-resistant (MR) staphylococci in aquatic environment is rarely investigated. Here, we characterized a collection of MR staphylococci recovered from shrimp aquaculture farms (n = 37) in Kerala, India. A total of 261 samples yielded 47 MR isolates (16 S. aureus, 13 S. haemolyticus, 11 S. epidermidis, 3 S. saprophytics and 2 each of S.intermedius and S. kloosii). Multi-drug resistance was evident in 72.3% of the isolates, with resistance mainly towards erythromycin (78.7%), norfloxacin and trimethoprim-sulfamethoxazole (53.2%), and gentamicin (34%). Major resistance genes identified included mecA (100%), ermC (38.3%), aacA-aphD (21.3%), tetK (14.9%) and tetM (21.3%). Almost 60% of the isolates carried type V SCCmec (Staphylococcal Cassette Chromosome mec), and the remaining harboured untypeable SCCmec elements. Comprehensive genotyping of the methicillin-resistant Staphylococcus aureus isolates revealed high prevalence of ST772-t345-V (sequence type-spa type-SCCmec type) (75%), followed by minor representations of ST6657-t345-V and ST3190-t12353. The isolates of S. haemolyticus and S. epidermidis were genotypically diverse as shown by their pulsed-field gel electrophoresis (PFGE) profiles. Genes encoding staphylococcal enterotoxins were observed in 53.2% of the isolates. Various genes involved in adhesion and biofilm formation were also identified. In conclusion, our findings provide evidence that shrimp aquaculture settings can act as reservoirs of methicillin-resistant staphylococci.

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从虾养殖场分离的耐甲氧西林葡萄球菌的基因型和表型

水环境中耐甲氧西林 (MR) 葡萄球菌的种群很少被调查。 在这里，我们对从印度喀拉拉邦的虾养殖场 ( n = 37)回收的一组 MR 葡萄球菌进行了鉴定。总共 261 个样品产生了 47 个 MR 分离物（16 个 金黄色葡萄球菌、13 个 溶血性葡萄球菌、11 个 表皮葡萄球菌、3 个 腐生葡萄球菌和 2 个中间葡萄球菌和克氏葡萄球菌）。72.3%的分离株出现多重耐药，主要对红霉素（78.7%）、诺氟沙星和复方磺胺甲恶唑（53.2%）、庆大霉素（34%）耐药。确定的主要抗性基因包括mecA (100%)、ermC (38.3%)、aacA-aphD (21.3%)、tetK (14.9%) 和tetM (21.3%)。几乎 60% 的分离株携带 V 型 SCC mec（葡萄球菌盒式染色体mec），其余的则含有不可分型的 SCC mec元件。对耐甲氧西林金黄色葡萄球菌的综合基因分型显示，ST772-t345-V（序列型-spa 型-SCC mec 型）的流行率很高（ 75 %），其次是 ST6657-t345-V 和 ST3190-t12353。溶血性链球菌和表皮链球菌的分离株如其脉冲场凝胶电泳（PFGE）图谱所示，基因型多样化。在 53.2% 的分离物中观察到编码葡萄球菌肠毒素的基因。还鉴定了涉及粘附和生物膜形成的各种基因。总之，我们的研究结果提供了对虾养殖环境可以作为耐甲氧西林葡萄球菌宿主的证据。