耐甲氧西林葡萄球菌HVR基因分型及其与耐药性的关系  

The HVR Genotypes and Their Relationship with the Resistance of Methicillin-Resistant Staphylococci

作　　者：廖昉[1] 范昕建[1] 吕晓菊[1] 冯萍[1] 

机构地区：[1]华西医科大学附属第一医院传染内科,成都610041

出　　处：《华西医科大学学报》2001年第2期167-171,共5页Journal of West China University of Medical Sciences

基　　金：国家自然科学基金资助!(批准号 3 9970 675 )

摘　　要：目的　为获得成都地区耐甲氧西林葡萄球菌的 HVR- PCR基因型 ,比较 HVR基因型与耐药谱的关系 ,从而指导临床合理选用抗生素 ,并初步探讨其在分子流行病学分析中的作用。方法　从成都地区四家三甲医院收集到临床分离的葡萄球菌 114株。其中 86株 MRSA、10株 MRSE(Mcr S.epidemidis)、5株 MSSE(Mcs S.epidemidis)、8株 MRSH(Mcr S.haemolyticus)和 5株 MSSH(Mcs S.haemolyticus) ,用琼脂平皿二倍稀释法测定其MIC值 ,改良的碱裂解法提取 DNA,应用 PCR技术 ,扩增 mec基因高变区 (HVR区 ) ,聚丙烯酰胺凝胶垂直板和琼脂糖凝胶电泳分型。结果　根据 PCR产物片段大小 ,MRSA、MRSE和 MRSH分别被分为 4种、3种和 2种基因型 ,其中有 9株 MRSE的 PCR扩增产物片段大小与 MRSA相同。 MRSA主要为 A、D型 ,分别占 5 2 .32 %和39.5 3% ;B、C型最为耐药 ,而 D型对多种药物敏感。 MRSE的 型为高度多重耐药株 ,而 型对多种抗生素敏感。MRSH的 a型比 b型耐药。结论　 HVR- PCR法对于由 MRSA引起的院内感染的流行病学调查是一种快速、简单、可靠的分型法 ,且有利于抗菌药物的选用。这种方法能够部分比较 MRSA菌株和耐甲氧西林的凝固酶阴性葡萄球菌 (Mcr CNSt)的 mec决定因子 ,从而探讨其起源。Objective To investigate the HVR PCR genotype of methicillin resistant Staphylococci in local hospitals and compare it with the antibiograms, with aview to selecting effective antibacterial agents, moreover, to discuss preliminarily its role in molecular epidemiology. Methods The minimal inhibitory concentrations(MICs) of 86 MRSA, 10 MRSE(Mc r S.epidemidis ), 5 MSSE(Mc s S.epidemidis ), 8 MRSH(Mc r S. haemolyticus ) and 5 MSSH(Mc s S. haemolyticus) clinical isolates collected from 4 local hospitals were tested by serial two fold agar dilution method; their DNA were extracted by moved basic lytic method, whose polymerase chain reaction(PCR) products amplified, based on the size of mec associated hypervariable region(HVR) were analyzed by PAG vertical and agarose gel electrophoresis. Results MRSA, MRSE and MRSH were grouped into 4, 3 and 2 HVR genotypes respectively according to the size of the PCR products. The PCR products amplified from 9 of 10 MRSE isolates were the same as the products amplified from MRSA isolates. MRSA strains in this study were mainly HVR genotypes A and D, which accounted for 52.32% and 39.53%; Genotypes B and C were the most multi drug resistant, but genotype D was multi sensitive. The Ⅰ genotype of MRSE was multi drug resistant, but its genotype Ⅲ was multi drug sensitive. The genotype a of MRSH was more resistant than genotype b. Conclusion These results suggest that HVR PCR genotype method is an easy and fast method for epidemiological investigation of nosocomial infections caused by MRSA, and it is helpful for clinical selection of antibacterial agents. This method can compare the mec determinants of MRSA and Mc r CNSt isolates and hence to search for the origin of the mec determinant.

关 键 词：耐甲氧西林葡萄球菌 基因高变区 分型 耐药性 HVR 

分 类 号：R446.5[医药卫生—诊断学]