苯唑西林和头孢西丁敏感金黄色葡萄球菌MecA基因检测研究

Detection of MecA Gene among Oxacillin and Cefoxitin-Susceptible Staphylococcus Aureus

目的:获得本地区苯唑西林和头孢西丁敏感金黄色葡萄球菌(SA)MecA基因携带率并分析其分子流行病学特征,为临床耐甲氧西林金黄色葡萄球菌(MRSA)感染的诊治提供循证学依据。方法:回顾性分析深圳大学附属南山医院微生物室2010年1月至2016年12月分离出的435株甲氧西林敏感金黄色葡萄球菌(MSSA)的临床药敏特点,总结其对苯唑西林和头孢西丁的耐药情况。应用聚合酶链式反应(PCR)方法扩增MecA基因,红霉素耐药基因ermA、ermB和ermC,扩增SA7对管家基因(arcc、aroe、glpf、gmk、pta、tpi、yqiL)。结果:在435株MSSA中发现2株对苯唑西林和头孢西丁敏感但MecA基因阳性的MRSA菌株,其多基因座顺序分型(MLST)分别为ST239和ST2631,标本均来源于痰液。ermA,ermB和ermC基因除ermA在菌株CHS172中检测阳性,其余均为阴性。结论:临床药敏实验提示苯唑西林和头孢西丁敏感的MSSA有必要进一步检测MecA基因,以验证耐药表型和指导临床治疗方案确定。

Objective Obtain the prevalence of MecA gene among oxacillin and cefoxitin-susceptible Staphylococcus aureus （S.aureus） in the district, analyze the characteristics of molecular epidemiology. Methods The antibiotic susceptibility of 435 clinical S.aureus strains isolated from microbiological laboratory of Shenzhen Nanshan People＇s Hospital during January 2010 to December 2016 was analyzed retrospectively. The ratio of oxacillin and cefoxitin-resistant S.aureus was also summarized. Polymerase chain reaction （PCR） was used for detecting MecA gene, erythromycin resistance genes of ermA, ermB and errnC as well as housekeeping genes of S.aureus including arcc, aroe, glpf, gmk, pta, tpi, yqiL. Results Two MeeA gene positive MRSA were identified, which were all isolated from sputum.The sequence types （STs） were ST239 and ST2631, respectively. Only ermA gene was positive in CHS172 strain among ermA,ermB and ermC. Conclusion it is necessary for oxacillin-and cefoxitin-susceptible S.aureus strains determined by clinical susceptibility testing to detect MecA gene, which is helpful to comfirm drug-resistant phenotype and guide clinical treatment.