医院感染甲氧西林耐药金黄色葡萄球菌的SCCmec 分型及同源性研究

摘要

Objective To investigate the staphylococcal chromosomal cassette mec (SCCmec)genotypes and molecular epidemi-ology of hospital-acquired MRSA.Methods A total of 26 non-duplicate MRSA isolates with the same resistant pattern were studied.SCCmec genotyping was analyzed by multiplex PCR.Repetitive element polymerase chain reaction (Rep-PCR)tech-nique was used to analyze the homology between these strains based on the DiversiLab system.Results The most common geno-type of these MRSA strains was SCCmec-III (84.6%).Two strains belonged to SCCmec-II and 1 SCCmec-IV.SCCmec-I strain was not identified.Based on the results of DiversiLab analysis,these MRSA strains were classified into 10 groups.The genetic similarity ranged from 40% to 100% among these SCCmec types.The two strains of SCCmec-II belonged to the same subtype.The similarity coefficient was higher than 90% for one strain of SCCmec-III subtype 1.The 4 strains of SCCmec-III subtype 3 were grouped into the same set with a similarity coefficient of > 95%.The MRSA strains of SCCmec-III subtype 2 was divided into 5 groups (similarity co-efficient > 90%).Conclusions SCCmec-III is the major genotype of MRSA isolates in our hospital.MRSA strains may spread in some wards.Clinicians and infection control department should pay close attention to this issue.%目的：研究多重耐药的甲氧西林耐药金葡菌（MRSA）菌株的 SCCmec 基因分型，并对菌株进行同源性分析。方法纳入26株耐药谱相同的 MRSA 菌株，采用多重 PCR 检测 SCCmec 的分型；应用 Rep-PCR 法采用 DiversiLab 系统对菌株进行同源性分析。结果26株 MRSA 的 SCCmec 多数为Ⅲ型，占84．6％，另检出Ⅱ型2株、Ⅳ型1株，1株未能分型；未发现Ⅰ型 SCCmec。DiversiLab 分析结果显示 MRSA 可分为10组，同源性介于40％～100％。其中 SCCmec-Ⅱ亚型2株完全相同。SCCmec-Ⅲ亚型subtype 1型相似性在90％以上；subtype 3型4株为同一组、MRSA 相似性在95％以上；subtype 2型可分为5组，相似性在90％以上。结论医院感染多重耐药的 MRSA 多数以 SCCmec-Ⅲ型为主，医院内存在一定流行，应引起临床医师及感染控制部门重视。