中国7所教学医院耐甲氧西林金黄色葡萄球菌的分子流行病学及耐药性研究

目的调查2007年中国7所教学医院耐甲氧西林金葡菌(MRSA)的分子流行病学分布及耐药性特征。方法采用多位点序列分型(MLST)和葡萄球菌蛋白A基因(spa)分型技术对114株MRSA进行分子流行病学研究,并进行Panton-Valentine毒素(PVL)编码基因lukS检测,采用琼脂稀释法进行13种抗菌药物的药敏试验。结果 114株MRSA中共发现8种MLST-spa分子克隆型,ST239-t030、ST239-t037和ST5-t002是主要的型别,分别占总数的41.2%、28.8%和21.9%。仅有1株MRSA检测到lukS基因阳性。MRSA菌株最敏感的抗菌药物为万古霉素与替考拉宁(100%),甲氧苄啶-磺胺甲口恶唑次之(86.8%);主要的分子克隆型ST239-t030、ST239-t037和ST5-t002菌株具有相似的药敏谱,但所有甲氧苄啶-磺胺甲口恶唑耐药菌株均属于ST239-t037。结论在中国MRSA的流行株由数种主要的分子克隆型引起,与周边国家和地区的情况基本一致。

Molecular epidemiology and antibiotic resistance of methicillin-resistant Staphylococcus aureus isolated from seven teaching hospitals in China

Objective To investigate the molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus （MRSA） strains collected from seven teaching hospitals in China in 2007. Methods Multilocus sequence typing （MLST） and Staphylococ cus protein A gene （spa） typing were used to type the 114 strains of MRSA. The lukS gene encoding Panton Valentine leukocidin （PVL） was detected. Antibiotic susceptibility testing was performed by agar dilution method. Results Among the 114 strains, eight MLST-spa molecular types were identified, of which ST239-t030, ST239-t037 and ST5- t002 were the most predominant types, accounting for 41.2%, 28. 8% and 21.9%, respectively. Only one MRSA strain was luleS positive. Vancomyein and tigecycline were most active against all the MRSA strains tested （100%）, followed by trimethoprim-sulfamethoxazole （86. 8%）. The major molecular types, ST239-t030, ST239-t037 and STS- t002, were found with similar susceptibility patterns. However, all strains resistant to trimethoprim-sulfamethoxazole were identified as ST239-t037. Conclusions The prevalence of MRSA in China is predominated by several major molecular clones, which is consistent with the situa tion in surrounding countries or regions.