医院获得性耐甲氧西林金黄色葡萄球菌中PSM-α基因检测及相关研究

Detection and related study of PSM-α gene in hospital-acquired methicillin-resistant Staphylococcus aureus

目的了解某地区耐甲氧西林金黄色葡萄球菌(MRSA)中α型-酚溶调制蛋白(PSM-α)基因携带情况及对人外周血中性粒细胞的影响,为指导临床治疗及明确该地区MRSA致病机制提供理论依据。方法收集临床标本中分离并经SCCmec分型的MRSA90株,采用聚合酶链反应(PCR)方法扩增PSM-α基因,并通过细胞形态学方法研究PSM-α对人外周血中性粒细胞的影响。结果 86株医院获得性MRSA(HA-MRSA)中,PSM-α基因阳性者78株,PSM-α阳性率为90.70%;4株社区获得性MRSA(CA-MRSA)中,2株为PSM-α基因阳性,阳性率为50.00%;PSM-α阳性组中性粒细胞死亡率与生理盐水组、PSM-α阴性组和ATCC25923组间比较,差异有统计学意义。PSM-α阳性组死亡率高于其他3组,而PSM-α阴性组和ATCC25923组差异无统计学意义。结论该地区HA-MRSA携带PSM-α基因,且PSM-α基因阳性的MRSA菌株分泌的PSM-α具有促进中性粒细胞溶解的活性。

Objective To investigate the carriage of phenol soluble modulin-α（PSM-α）in methicillin-resistant Staphylococcus aureus（MRSA）and influence in human peripheral blood neutrophils,so as to provide theoretical ba-sis for guiding clinical treatment and identifying pathogenesis of MRSA. Methods Ninety MRSA isolates which were isolated from clinical specimens and performed SCCmec genotyping were collected,PSM-αgene was amplified by polymerase chain reaction（PCR）,and the effects of PSM-αgene on hunman peripheral blood neutrophils was studied by cell morphology analysis.Results Of 86 hospital-acquired MRSA（HA-MRSA）isolates,78 were positive for PSM-αgene,the positive gene was 90.70% ;Of 4 community-acquired MRSA（CA-MRSA）,2 were positive for PSM-αgene,the positive rate was 50.00% ;neutrophil death rate in PSM-αpositive group was significantly higher than normal saline group,PSM-αnegative group and ATCC 25923 group,but there was no significant difference between PSM-αnegative group and ATCC 25923 group. Conclusion HA-MRSA detected in this region carry PSM-αgene,and PSM-αsecreted by PSM-αpositive MRSA has the activity of promoting the lysis of neutrophils.