耐甲氧西林金黄色葡萄球菌基因型及其与耐药性的关系

Genotypes of methicillin resistant Staphylococcus aureus and its relationship with resistance

目的 :了解耐甲氧西林金黄色葡萄球菌 (MRSA)基因型及其与耐药性的关系 ,为MRSA感染的治疗选药及分子流行病学研究提供实验依据。方法 :用聚合酶链反应 (PCR)方法扩增MRSAmec基因高变区 (HVR) ,据扩增片段大小差异进行基因分型 ,结合 5种抗菌药物的MIC值 ,分析基因型与耐药性的关系。结果 :86株MRSA被分为A、B、C、D 4种基因型 ,以A(5 2 .3%)、D(39.5 %)型多见 ,B、C型少见 ,但后 2型耐药性更高 ,各型菌均对万古霉素敏感。结论 :治疗MRSA感染以选万古霉素 ,或联合阿米卡星、利福平为宜 ,HVR基因分型可作为MRSA感染分子流行病学研究的新手段。

Objective: To investigate the genotype of methicillin resistant Staphylococcus aureus (MRSA) and its relationship with resistant profiles. Method: A total of 86 non-duplicate MRSA clinical isolates were collected in Chengdu. MIC of five different antibacterial agents against the isolates were determined by agar dilution method. PCR amplified the mec associated hypervariable region (HVR) of MRSA, and the genotypes were classified based on the fragments of amplified products. The correlation of genotypes and antimicrobial resistance was analyzed. Results: 86 strains of MRSA from Chengdu were grouped into A, B, C and D genotypes based on HVR polymorphism, the most common types were A(52.3%) and D(39.5%), followed by B and C. Most strains of genotype B and C were multi-drug resistant. All strains were sensitive to vancomycin. Conclusions: MRSA were multi-drug resistant, and can be divided into 4 genotype based on the HVR PCR amplified products. HVR PCR method is a rapid and convenient method for molecular epidemiology study of MRSA infections, vancomycin or vancomycin combined with amikacin or rifampin may be the effective treatment for MRSA infections.