成都地区骨科患者伤口金黄色葡萄球菌感染的分子流行病学及耐药性分析

Analysis of molecular epidemiology and drug-resistance on Staphylococcus aureus isolated from wounds of orthopedic patients in Chengdu

目的:分析四川成都地区骨科伤口感染金黄色葡萄球菌的分子流行病学特征与耐药现状.方法:收集2016年9月至2019年9月成都地区西部战区总医院骨科分离自伤口分泌物的金黄色葡萄球菌,进行耐甲氧西林金黄色葡萄球菌(MRSA)鉴定及其SCCmec分型、各菌株MLST分型和spa分型.聚合酶链式反应(PCR)检测20种金黄色葡萄球菌常见毒力因子,并对12种常用抗菌药物进行药敏分析.所有结果同时进行MRSA与甲氧西林敏感金黄色葡萄球菌(MSSA)菌株间的比较.结果:195株细菌MRSA检出率为21.0%,MRSA以SCCmecⅠ(41.5%)、Ⅳ(36.6%)型为主,MLST型别主要为ST59(58.5%)和ST630(17.1%),spa型别主要为t437(43.9%);MSSA的MLST主要型别为ST188(22.1%)和ST6(13.6%),spa型别主要为t189(19.5%)和t701(10.4%).MRSA菌株hlb(P<0.01)和seb(P<0.01)基因携带率较高,而cna(P<0.01)和ebpS(P<0.05)基因携带率较低,且这一结果与分子分型相关.耐药分析提示某些抗生素可在经验性抗金黄色葡萄球菌中优先选择.结论:成都地区骨科伤口感染金黄色葡萄球菌主要为ST59/ST630-t437-MRSA-SCCmecⅠ/Ⅳ和ST188-t189-MSSA.分子分型结果与毒力因子携带情况密切相关,本研究结果对本地区抗菌策略的制定有一定参考作用.

Objective:To analyze molecular epidemiologic and drug-resistance characteristics of Staphylococcus aureus strains isolated from wounds of orthopedic patients in Chengdu,Sichuan province.Methods:S.aureus strains isolated from wounds of orthopedic patients in western theater general hospital of Chengdu from September 2016 to September 2019 were collected in this study.Methicillin-sensitive Staphylococcus aureus(MRSA)identification,SCCmec typing of MRSA,MLST and spa typing of all strains were performed.Twenty virulence genes of S.aureus were tested by polymerase chain reaction(PCR).Drug-resistance of twelve common antimicrobials was also tested.All the results were compared between MRSA and methicillin-sensitive Staphylococcus aureus(MSSA)strains.Results:A total of 195 isolates were included into this study.The detection rate of MRSA was 21.0%.SCCmec I(41.5%)and IV(36.6%)were the main SCCmec types of MRSA strains.The main MLST types of MRSA were ST59(58.5%)and ST630(17.1%),and the predominant spa type was t437(43.9%).For MSSA strains,ST188(22.1%)and ST6(13.6%),t189(19.5%)and t701(10.4%)were the main MLST and spa types,respectively.Comparing with MSSA strains,carriage rates of hlb(P<0.01)and seb(P<0.01)genes were higher,and lower for cna(P<0.01)and ebpS(P<0.05)genes,in MSRA strains.Moreover,these results were closely related to the molecular typing results.Drug-resistance analyses suggested that some antimicrobials might be better for empirical therapy against S.aureus infections.Conclusion:The predominant molecular types of S.aureus strains isolated from wounds of orthopedic patients in Chengdu were ST59/ST630-t437-MRSA-SCCmec I/IV and ST188-t189-MSSA.The molecular typing results were closely related to the carriage of virulence genes.Our results will benefit the formulation of antibacterial strategies.