血液感染金黄色葡萄球菌gyrA基因突变与耐药性关系研究  

A study of the relationship between mutations in the gyrA gene of Staphylococcus aureus infecting patients with a bloodstream infection and its drug resistance and the rational selection of antibiotics

作　　者：梁军 陶琳 康向伟 

机构地区：[1]莱芜市妇幼保健院,山东莱芜271100 [2]莱芜市莱城区卫生局,山东莱芜271100

出　　处：《中国病原生物学杂志》2015年第2期184-187,共4页Journal of Pathogen Biology

摘　　要：目的探讨血液感染患者感染的金黄色葡萄球菌gyrA基因突变情况与其耐药性之间的关系,为合理选用抗生素治疗血液感染提供参考。方法分离血液感染患者组织中的金黄色葡萄球菌并进行药敏试验,对其gyrA基因进行扩增及测序;采用琼脂稀释法进行药敏试验,分析其突变位点及与其耐药性间的关系。结果血液感染金黄色葡萄球菌分离株对环丙沙星、氧氟沙星、洛美沙星、诺氟沙星、司帕沙星及恩诺沙星均产生不同程度的耐药,MIC50最小为28μg/ml,MIC90最小为112μg/ml,其耐药率最小为42.0%。PCR法扩增金黄色葡萄球菌的gyrA基因,大小为565bp;基因测序显示gyrA基因的73位、82位由天冬氨酸(GAC)突变为甘氨酸(GGC),81位由丝氨酸(TCA)突变为甘氨酸(TTC),84位由丝氨酸(TCA)突变为丙氨酸(GCA)或亮氨酸(TTA),88位由谷氨酸(GAA)突变为赖氨酸(AAA),106位由甘氨酸(GGA)突变为天冬氨酸(GAA),112位由丝氨酸(TCA)突变为精氨酸(TCG),这些氨基酸突变情况与其耐药性关系密切。结论血液感染患者感染的金黄色葡萄球菌gyrA基因发生突变,导致其编码的氨基酸发生变化,进而导致菌株产生耐药性,可为血液金黄色葡萄球菌感染的治疗提供参考。Objective To examine the relationship between the mutations in the gyrA gene of Staphylococcus aureus infecting patients with a bloodstream infection and its drug resistance in order to select antibiotics more rationally and better guide the clinical treatment of bloodstream infections. Methods S.aureus was isolated and drug sensitivity was tested using agar dilution.The gyrA gene was amplified and sequenced,and the relationship between mutations and drug resistance was analyzed. Results A drug sensitivity test was performed using agar dilution.S.aureusisolates from patients with a bloodstream infection displayed varying levels of drug resistance to ciprofloxacin,ofloxacin,lomefloxacin,norfloxacin,sparfloxacin,and enrofloxacin.The minimum MIC50 was 28μg/ml,the minimum MIC90 was 112μg/ml,and the lowest drug resistance was 42.0%,indicating that these antibiotics cannot be the drug of choice for the clinical treatment of S.aureus infection.The gyrA gene of S.aureus was successfully amplified using PCR.The gene was 565 bp in length.Gene sequencing indicated a mutation from aspartic acid（GAC）to glycine（GGC）at codon 73 and codon 82 of the gyrA gene,a mutation from serine（TCA）to glycine（TTC）at codon 81,a mutation from serine（TCA）to alanine（GCA）or leucine（TTA）at codon 84,a mutation from glutamic acid（GAA）to lysine（AAA）at codon 88,a mutation from glycine（GGA）to aspartic acid（GAA）at codon 106,and a mutation from serine（TCA）to arginine（TCG）at codon 112.The state of these amino acid mutations was closely related to drug resistance. Conclusion The gyrA gene of S.aureus infecting patients with a bloodstream infection had mutated,causing a change in the amino acids that it coded for.This in turn produced drug-resistant strains.These findings should provide effective guidance for the clinical treatment of bloodstream infections.

关 键 词：血液感染 金黄色葡萄球菌 GYRA基因 耐药性 抗生素 

分 类 号：R378.11[医药卫生—病原生物学]