金黄色葡萄球菌的耐药性分析与基因分型研究

Study on antimicrobial resistance and genotypes of Staphylococcus aureus

目的了解金黄色葡萄球菌临床分离株的耐药性及其分子流行病学特征,为临床耐甲氧西林金黄色葡萄球菌(MRSA)感染的预防治疗提供参考。方法采用纸片扩散法检测2012年1-12月临床分离的42株金黄色葡萄球菌的耐药性,并对MRSA进行判定;应用多重PCR法对MRSA进行SCCmec分型,并用PCR方法扩增其spa基因,测序后通过数据库进行spa分型。结果 42株金黄色葡萄球菌中共检出28株MRSA,检出率为66.7%;金黄色葡萄球菌对呋喃妥因、喹奴普汀/达福普汀和万古霉素均100.0%敏感,MRSA对头孢类、氟喹诺酮类和大环内酯类抗菌药物的耐药率明显高于甲氧西林敏感金黄色葡萄球菌(MSSA),差异有统计学意义(P<0.05);MRSA的SCCmec基因型以SCCmecⅡ型为主,占89.3%,SCCmecⅢ型占10.7%,28株MRSA共检测到6个spa型别,包括spa-t311型15株、spa-t002型8株、spa-t030型2株,spa-t034、spa-t127、spa-t14165型各1株,其中spa-t14165为该研究发现的新spa型。结论 MRSA占金黄色葡萄球菌比例较高,主要流行株为SCCmecⅡ型菌株,spa分型以spa-t311克隆型和spa-t002克隆型为主,spa-t14165为新型临床多耐药菌株。

OBJECTIVE To investigate the drug resistance of the clinical isolates of Staphylococcus aureus and observe the epidemiological characteristics so as to provide guidance for clinical treatment of infection due to methicillin‐resistant Staphylococcus aureus （MRSA） .METHODS From Jan to Dec ,2012 ,the drug resistance of 42 clinical S .aureus isolates was determined by using disk diffusion method ,and the MRSA strains were indentified . SCCmec genotyping was conducted with the use of multiplex PCR method ,the spa gene was amplified by using PCR ,and the spa genotypes were confirmed based on the databases after the sequencing .RESULTS A total of 28 strains of MRSA have been detected among the 42 S .aureus isolates ,with the detection rate of 66 .7% .The S . aureus isolates were 100 .0% susceptible to nitrofurantoin ,quinupristin‐dalfopristin ,and vancomycin ;the drug resistance rates of the MRSA to cephalosporins ,fluoroquinolones ,and macrolides were significantly higher than those of the methicillin‐sensitive Staphylococcus aureus （MSSA） ,and there was significant difference （P〈0 .05） . The SCCmec Ⅱ was the predominant genotype of SCCmec in the MRSA ,accounting for 89 .3% ,followed by the SCCmec Ⅲ （10 .7% ） .Totally 6 spa types have been detected in the 28 strains of MRSA ,including the spa‐t311 in 15 strains ,spa‐t002 in 8 strains ,spa‐t030 in 2 strains ,spa‐t034 in 1 strain ,spa‐t127 in 1 strain ,and spa‐t14165 in 1 strain;the spa‐t14165 was a novel spa type that was detected in the study .CONCLUSIONS The MRSA stains occupy a higher proportion of the S .aureus isolates ;the SCCmec Ⅱ is the predominant type in the study , and the spa‐t311 clone type and spa‐t002 clone type are dominant among the spa types ;the spa‐t14165 is the novel type in the clinical multidrug‐resistant strains .