耐甲氧西林金黄色葡萄球菌耐药表型分型与耐药基因检测分析研究

Antibiotic resistance phenotype and gene detection of methicillin-resistant staphylococcus aureus

目的分析研究耐甲氧西林金黄色葡萄球菌（methicillin-resistant staphylococcus aureus,MRSA）的耐药表型及耐药基因,探索治疗MRSA感染的有效手段。方法对临床分离的耐甲氧西林金黄色葡萄球菌株,依据美国临床实验室标准化研究所（CLSI）标准操作规程进行万古霉素、利奈唑胺和苯唑西林等药物的药物敏感性试验和耐药基因检测,分别采用微量肉汤稀释法和多重聚合酶链反应（PCR）扩增法。结果 MRSA耐药表型分为Ⅰ~Ⅶ型,MRSA对抗生素产生多重耐药,万古霉素、利奈唑胺、氯霉素、复方新诺明、利福平耐药率分别为0、7.0%、40.8%、47.9%、60.6%,β-内酰胺类药物耐药率高达100%;实验菌株mecA、ermA、ermC、tetK、tetM、ratA基因检出率分别为98.6%、60.6%、18.3%、100%、7.0%和0。结论 MRSA对万古霉素、利奈唑胺敏感,其他药物呈多重耐药,需加强MRSA对万古霉素、利奈唑胺、氯霉素、复方磺胺、利福平等常用药物最小抑菌浓度（MIC）监测和临床报告,关注万古霉素对MRSA治疗不佳患者。

Objective To identify the phenotypes and genes of antibiotic resistance in methicillin-resistant staphylococcus aureus（MRSA）,and to explore the effective approach for control of MRSA infection.Methods Vancomycin,linezolid and oxacillin resistance tests and gene detections were performed on the clinically isolated MRSA strains using trace broth diluting technique and multiple polymerase chain reaction that were in line with standardized operating procedures established by American Clinical Laboratory Standardization Institute（CLSI）.Results MRSA strains were divided into phenotypes Ⅰ~Ⅶ,which had developed multiple antibiotic resistance.The resistance rate of vancomycin,linezolid,chloramphenicol,compound trimethoprim-sulfamethoxazole,rifampicin and β-lactams was 0,7.0%,40.8%,47.9%,60.6% and 100%,respectively.Detectable rate of strains containing resistance genes of mecA,mecA、ermA、ermC、tetK、tetM、ratA was 98.6%、60.6%、18.3%、100%、7.0% and 0,respectively.Conclusion MRSA strains were sensitive to vancomycin and linezolid but resistant to multiple antibiotics.Clinical reports concerning in-tensive monitoring on minimal inhibitory concentration of antibiotics including vancomycin,linezolid,chloramphenicol,compound trimethoprim-sulfamethoxazole and rifampicin needs to be directed.Attention should also be attached to those with poor response to vancomycin.