金黄色葡萄球菌sasX、psm-mec、pvl三种毒力基因的检测与分析

Detection and analysis of virulence genes sasX,psm-mec and pvl in Staphylococcus aureus

目的分析54株金黄色葡萄球菌的mecA基因与sasX、psm—mec．pvl三种毒力基因分布及临床相关性。方法收集2013年1～5月南京医科大学第一附属医院临床分离的54株金黄色葡萄球菌，用PCR及测序的方法分析mecA、sasX、psm-mec、pvl基因的携带情况，并结合患者的临床资料，探讨其临床相关性。结果54株金黄色葡萄球菌中有23株mecA基因检测阳性，31株mecA基因阴性。mecA基因阳性菌株较mecA基因阴性株体外药敏试验呈多重耐药表型。sasX基因阳性1株，阳性率为1．9％；psm-mec基因阳性10株，阳性率为18．5％；pvl基因阳性38株，阳性率为70．4％。mecA基因阳性菌株psm—mec基因阳性率显著高于mecA基因阴性菌株（P〈0．01），pvl基因阳性率显著低于mecA基因阴性菌株（P〈0．05）。mecA基因和psm-mec基因与临床感染严重程度显著相关（P均〈0．01）。结论联合检测mecA、psm—mec和pvl基因有利于金黄色葡萄球菌感染的诊断、治疗和预后综合评估。

Objective To investigate the distribution and clinical association of mecA gene and virulence genes sasX, psm-mec and pvl from 54 isolates of Staphylococcus aureus （ S. aureus）. Methods Fifty-four isolates of S. Aureus were collected from the patients hospitalized in the First Affiliated Hospital of Nanjing Medical University during January 2013 to May 2013. Then, the mecA, sasX, psmmec and pvl genes from 54 isolates of S. Aureus were determined by PCR and DNA sequencing, and their clinical association were further analyzed. Results Twenty-three isolates of S. aureus carried mecA gene, while the other 31 didn＇t. Moreover, the isolates carried with mecA displayed the phenotype of multiple drug resistance. Among 54 isolates of S. Aureus, 1 （ 1.9% ） carried with sasX gene, 10 （18.5%） with psm-mec, and 38 （70.4%） with pvl. The positive rate of psm-mec gene in the isolates carried mecA was significantly higher than that in the isolates without mecA （P 〈 0.01 ）, while the positive rate of pvl gene was significantly lower than that in the methicillin-sensitive isolates （ P 〈 0.05 ）. There was significant association between mecA and psm-mec genes and clinical infection （ P 〈 0. 01 ）. Conclusion Combined detection of mecA, psm-mec and pvl genes will be helpful for the diagnosis, treatment and prognosis of S. aureus infection.