粪肠球菌gyrA基因突变与氟喹诺酮类耐药性关系的研究

目的探讨粪肠球菌DNA促旋酶A亚单位（gyrA）基因突变与氟嚎诺酮类耐药的关系。方法琼脂稀释法测定粪肠球菌对各种氟喹诺酮类药物的耐药情况；聚合酶链反应（PCR）结合单链构象多态性（SSCP）分析检测gyrA中氟哇诺酮类耐药决定区（QRDR）突变情况。结果粪肠球菌对诺氟沙星耐药率为78．1％（50／64），加替沙星为54．7％（35／64）。41株耐药菌的第87位氨基酸编码碱基发生突变（GAA→GGA）。结论加替沙星的耐药率较低，优于其他氟哇诺酮类药物；gyrA基因突变是粪肠球菌对氟喹诺酮类耐药的重要原因。

Relationship between the mutation of gyrA gene in Entero-coccus faecalis and the drug resistance of fluroquinolone

Objective: To detect the mutation in fluroquinolone-resistant Enterococcus faecalis,and study the relationship between the resistance and mutation of gyrA.Methods: Obtained fluroquinolone-resistant Enterococcus faecalis by agar dilution method.The gyrA gene was amplified with PCR,and mutation was detected with SSCP and sequencing.Results: 78.1% Enterococcus faecalis resisted to fluroquinolone,and(54.7%) to gatifloxacin.Mutation was found in 41 strains of fluroquinolone-resistant Enterococcus faecalis,which was from Glu to Gly,and no mutation in other 9 strains.Conclusion: Gatifloxacin is better than other fluroquinolones.Mutation in gyrA is an important reason for fluroquinolone resistance.Other mechanisms maybe take part in the fluroquinolone resistance.