Department of Food and Agriculture, University of La Rioja, Logroño, Spain.
Institute of Microbiology and Epizootics, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
Vet Microbiol. 2020 Apr;243:108631. doi: 10.1016/j.vetmic.2020.108631. Epub 2020 Feb 28.
This work aimed at characterizing four Staphylococcus aureus and 68 coagulase-negative staphylococci (CoNS), recovered from the air and liquid manure tank of two swine farms with intensive- and semi-extensive-production types, for their antimicrobial resistance pheno-/genotypes and their virulence gene content. Molecular typing was performed by spa typing, MLST, agr typing, and SCCmec typing, where applicable. Conjugation experiments were performed to assess the transferability of the linezolid resistance gene cfr, and its genetic environment was determined by Whole-Genome-Sequencing. The four S. aureus (intensive-production farm, IP-farm) were typed as t011-agrI-CC398-ST398, were scn-negative and two of them were methicillin-resistant (MRSA) with the mecA gene (SCCmec-V). Multidrug resistance was seen in 87 % of the CoNS. Statistically significant differences among the antimicrobial resistance rates of CoNS from the two farms were observed for cefoxitin, aminoglycosides, tetracycline, ciprofloxacin and trimethoprim-sulfamethoxazole. Eight methicillin-resistant CoNS, which were recovered from the IP-farm, carried the mecA gene. One S. simulans isolate was PVL-positive and three S. cohnii eta-positive. One S. equorum and one S. arlettae showed linezolid resistance and carried the cfr gene (IP-farm), which was non-transferable by conjugation into S. aureus. The cfr genetic context in both isolates was identical, with the lsa(B) gene located upstream of cfr. The environment of swine farms might contribute to the dissemination of CoNS that show multidrug resistance and harbor important virulence factors.
本研究旨在对从集约化和半集约化生产类型的两个养猪场的空气和液体粪肥罐中回收的 4 株金黄色葡萄球菌和 68 株凝固酶阴性葡萄球菌（CoNS）进行表型/基因型的抗菌药物耐药性和毒力基因含量分析。通过 spa 分型、MLST、agr 分型和 SCCmec 分型（视情况而定）进行分子分型。进行了接合实验以评估利奈唑胺耐药基因 cfr 的可转移性，并通过全基因组测序确定其遗传环境。这 4 株金黄色葡萄球菌（集约化生产场，IP 场）的型别为 t011-agrI-CC398-ST398，均为 scn 阴性，其中 2 株为耐甲氧西林金黄色葡萄球菌（MRSA），携带 mecA 基因（SCCmec-V）。CoNS 的多重耐药率为 87%。从两个养殖场分离的 CoNS 的抗菌药物耐药率存在统计学显著差异，其中包括头孢西丁、氨基糖苷类、四环素、环丙沙星和复方磺胺甲噁唑。从 IP 场分离出的 8 株耐甲氧西林 CoNS 携带 mecA 基因。1 株 S. simulans 分离株为 PVL 阳性，3 株 S. cohnii eta 阳性。1 株 S. equorum 和 1 株 S. arlettae 对利奈唑胺表现出耐药性，并携带 cfr 基因（IP 场），该基因不能通过接合转移到金黄色葡萄球菌中。两个分离株的 cfr 遗传环境完全相同，lsa(B) 基因位于 cfr 上游。猪场环境可能有助于携带重要毒力因子的多重耐药 CoNS 的传播。
