苯唑西林敏感mecA基因阳性金黄色葡萄球菌的鉴定与分析

目的 分析临床分离金黄色葡萄球菌(Staphylococcus aureus,S.aureus)中苯唑西林敏感mecA基因阳性的金黄色葡萄球菌(OS-MRSA)的发生率和生物学特性,为临床预防和治疗S.aureus感染提供理论依据。方法 临床分离的872株S.aureus经全自动微生物分析仪鉴定及药物敏感性检测,表型分析判定苯唑西林耐药金黄色葡萄球菌(MRSA)菌株和苯唑西林敏感金黄色葡萄球菌(MSSA)菌株；采用聚合酶链式反应(PCR)检测mecA基因和其他金黄色葡萄球菌特异基因,通过对比表型和基因分析结果鉴定出OS-MRSA。结果 872株S.aureus 根据临床表型分析判定610株苯唑西林耐药(MRSA)菌株,262株苯唑西林敏感(MSSA)菌株,筛选鉴定出5株OS-MRSA,共4种基因类型,其中有两株属于同一基因类型。结论 该院两年内临床S.aureus感染中根据表型分析MRSA占70%,MSSA占30%,而OS-MRSA占“MSSA”的2%。

Identification of the Oxacillin-Susceptible mecA-positive Staphylococcus aureus

Objective To investigate the incidence and biological characteristics of the oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) from clinical isolates of S.aureus,and to provide theoretical basis for the clinical prevention and treatment of S.aureus infection.Methods 872 S.aureus isolated from clinical specimens were identified,and drug sensitivity was analyzed by automatic microbial analyzer.Oxacillin resistant S.aureus (MRSA) strains and oxacillin susceptible S.aureus (MSSA) strains were determined by the phenotype results.Polymerase chain reaction (PCR) was used to detect the mecA gene and other S.aureus specific genes.OR-MRSA stains were screened by contrasting the phenotypic and genetic results.Results 610 strains of MRSA and 262 strains of MSSA were classified according to the clinical phenotype analysis.5 stains of OS-MRSA were screened and 2 strains of which belonged to the same gene type.Conclusion The clinical S.aureus infection in our hospital accounts for 70% MRSA and 30% MSSA,according to the phenotypic analysis during the two years.However,2% of “MSSA” strains are OS-MRSA.