【摘要】 目的 建立耐甲氧西林金黄色葡萄球菌的快速检出方法。方法 利用聚合酶链反应 (PCR) 技术快速检出耐甲氧西林金黄色葡萄球菌(金葡菌)，建立一种从葡萄球菌中快速提取DNA方法，以粗提DNA作为PCR模板，检测编码耐甲氧西林金葡菌青霉素结合蛋白2a(PBP_2a )的mecA基因。结果 184株金葡菌用PCR方法及药敏法比较，药敏法鉴定为耐甲氧西林金葡菌(MRSA)58株，仅一株PCR扩增mecA基因阴性。126株甲氧西林敏感的金葡菌(MSSA)中有3株mecA基因阳性。用酶促生物素标记寡核苷酸探针进行Southern blot分析，杂交结果与PCR结果一致，证实533 bp片段为MRSA mecA基因特异性片段。结论 PCR方法能较准确检出MRSA，尤对临界浓度者(MIC为0.5～4 mg/L)较常规方法优越。

Rapid detection of methicillin-resistant Staphylococcus aureus by using polymerase chain reaction Mo Lan, Wang Qinan. Department of Infectious Diseases, First Affilliated Hospital, Chongqing University of Medical Science, Chongqing 400016

     【Abstract 】 Objective To identify methicillin-resistant S. aureus (MRSA) with a simple and reliable method, polymerase chain reaction (PCR). Methods A rapid cell lysis procedure was established for the release of DNA from staphylococci. By using crude extract of the strain to be tested as template and 22-mer oligonucleotides as primers, a 533 bp region of mecA gene, We amplified the structural gene of a low affinity penicillin binding protein 2a (PBP_2a ) by PCR and detected by 2% agarose gel electrrophoresis. Results The results were compared with those obtained by broth double-dilution MIC determination for 184 clinical isolates of S.aureus. 57 of 58 strains of oxacillin-resistant S.aureus were mecA positive as determined by PCR, whereas only one strain of oxacillin-resistant S. aureus was mecA negative. Three strains of 126 oxacillin-susceptible S. aureus were mecA positive. In southern blot ana-lysis of PCR products by using an 18-mer oligonucleotides as a probe, labeled with Bio-11-dUTP, the results of DNA hybridization were correlated with those of PCR test. Conclusion The strains of S. aureus with borderline oxacillin resistance (MIC=0.5 ～4.0 mg/L) can be accurately identified with PCR method.

     【Key words 】 Polymerase chain reaction Staphylococcus aureus mecA gene

自1961年发现耐甲氧西林金黄色葡萄球菌(MRSA)以来 ......