Sydney School of Veterinary Science, University of Sydney, NSW, Australia.
Antimicrobial Resistance and Infectious Diseases Laboratory, School of Veterinary Life Sciences, Murdoch University, Murdoch, Western Australia, Australia.
Vet Microbiol. 2018 Jan;213:58-65. doi: 10.1016/j.vetmic.2017.11.018. Epub 2017 Nov 21.
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an increasingly prevalent pathogen in veterinary medicine. This study examined the molecular epidemiology of clinical MRSP isolated from Australian animals. Clinical staphylococci submitted to all Australian veterinary diagnostic laboratories were collected during 2013 and identified using traditional phenotypic tests and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Phenotypic antimicrobial resistance was determined using broth microdilution and disk diffusion. MRSP isolates were characterized by whole genome sequencing which included identification of the mecA gene. Phylogenetic relationships were inferred by comparison of single nucleotide polymorphisms. Of the 669 S. pseudintermedius isolates collected from dogs, cats and cattle, 77 (11.5%) were MRSP. Nineteen multilocus sequence types (STs) were identified, with most isolates belonging to one of five STs (ST71, ST497, ST316, ST496 and ST45). Phylogenetic analysis revealed that Australian ST71 appears closely related to ST71 from overseas. ST497 and ST496 represented novel sequence types, not previously reported outside Australia. Most other STs were novel and only distantly related to each other. Geographical clustering of STs was observed. All isolates belonging to the five main STs were multi- to extensively- drug resistant while isolates from singleton STs generally had lower levels of antimicrobial resistance. The frequency of ciprofloxacin, trimethoprim-sulfamethoxazole, gentamicin, chloramphenicol and tetracycline resistance varied significantly between STs (p<0.01). Australian MRSP isolates are phylogenetically diverse, with a mix of previously unreported and well known international MRSP clones that demonstrate geographic clustering and exhibit both multidrug-resistant and extensively drug-resistant phenotypes.
耐甲氧西林金黄色葡萄球菌（MRSP）是兽医领域日益流行的病原体。本研究检测了来自澳大利亚动物的临床分离 MRSP 的分子流行病学。2013 年，从所有澳大利亚兽医诊断实验室收集了临床葡萄球菌，并使用传统表型试验和基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）进行鉴定。使用肉汤微量稀释法和药敏纸片扩散法测定表型抗微生物药物耐药性。通过全基因组测序鉴定 MRSP 分离株，包括 mecA 基因的鉴定。通过比较单核苷酸多态性推断系统发育关系。从狗、猫和牛中收集的 669 株中间葡萄球菌分离株中，77 株（11.5%）为 MRSP。确定了 19 种多位点序列型（ST），大多数分离株属于 5 种 ST 之一（ST71、ST497、ST316、ST496 和 ST45）。系统发育分析显示，澳大利亚 ST71 与海外 ST71 密切相关。ST497 和 ST496 代表新型序列型，此前未在澳大利亚以外地区报道过。其他大多数 ST 是新型的，彼此之间仅存在远缘关系。观察到 ST 的地理聚类。属于五个主要 ST 的所有分离株均为多药至广泛耐药，而来自单峰 ST 的分离株通常具有较低水平的抗微生物药物耐药性。ST 之间的环丙沙星、甲氧苄啶-磺胺甲恶唑、庆大霉素、氯霉素和四环素耐药率差异显著（p<0.01）。澳大利亚 MRSP 分离株具有遗传多样性，既有以前未报告过的，也有众所周知的国际 MRSP 克隆，这些克隆表现出地理聚类，并表现出多药耐药和广泛耐药表型。
