临床分离耐氟喹诺酮类金黄色葡萄球菌的gyrA基因单点突变研究

Study on the DNA gyrA Gene Mutation with Resistance to Fluoroquinolones in Staphylococcus Aureus Isolated from Patients

为研究临床分离金黄色葡萄球菌 (简称金葡菌 )对氟喹诺酮类药物的耐药机理 ,采用聚合酶链反应 -限制性长度多态性分析方法 ,对成都地区 6 3株临床分离出的金葡菌 (其中 5 7株为氟喹诺酮类耐药株 ,6株为野生型敏感株 )的 gyr A基因单点突变与细菌耐氟喹诺酮类药物的关系进行了研究。结果 :在对诺氟沙星、氟罗朔星、托舒沙星、环丙沙星、氧氟沙星、司帕沙星分别耐药的菌株中 ,gyr A基因发生单点突变率达 6 7.2 7%～ 92 .5 % ,且多数 gyr A基因突变菌株呈高水平耐药。结论 :成都地区临床分离的对氟喹诺酮类药物耐药金葡菌多数发生了 gyr

This study was aimed at the mechanism of resistance to fluoroquinolones in Staphylococcus aureus isolated from patients in Chengdu. The relationship between the point mutations in the gyrA genes and the resistance of 63 strains (57 fluoroquinone resistant strains and 6 wild types) isolated clinically in Chengdu were investigated by a combination of restriction fragment length polymorphism analysis. The results revealed that there are 67.27% 92.5% of the fluoroquinolone resistant strains against norfloxacin, fleroxacin, tosufloxacin, cipofloxacin, ofloxacin and sparfloxacin had a Hinf Ⅰ site mutation in the gyrA genes, and most of such strains with such mutation in the gyrA genes showed high level resistance. These indicate that Hinf site mutation in gyrA genes is the mainly cause of the resistance of fluoroquinolone resistant strains of Staphylococcus aureus in Chengdu region.