临床分离耐甲氧西林金黄色葡萄球菌的耐药基因分型及药敏性分析

Drug resistance genotyping and drug susceptibility analysis of clinically isolated methicillin-resistant Staphylococcus aureus

目的分析临床分离耐甲氧西林金黄色葡萄球菌(MRSA)的耐药基因分型及药敏性。方法选择2018年3月至2020年7月南京市高淳人民医院住院及门诊患者各类临床标本中分离的254株金黄色葡萄球菌(SA)。采用普通聚合酶链式反应(PCR)检测mecA基因,采用多重PCR技术对MRSA分离株进行葡萄球菌染色体mec基因盒(SCCmec)基因分型,采用纸片扩散法(K-B)法对SCCmecⅡ型与SCCmecⅢ型进行药敏试验。结果头孢西丁K-B结果显示,254株SA中共检出156株初筛MRSA阳性株,MRSA初筛阳性率为61.42%。mecA基因PCR扩增结果显示,254株中共检出150株MRSA确认阳性株,检出率为59.06%。多重PCR结果显示,150株MRSA中SCCmecⅡ型39株,SCCmecⅢ型86株,SCCmecⅣa、SCCmecⅣb型各2株,未分型21株。SCCmecⅡ型与SCCmecⅢ型对苯唑西林、氨苄西林/舒巴坦、头孢西丁、美罗培南、青霉素G、头孢唑林的耐药性均为100.00%,SCCmecⅢ型对环丙沙星、红霉素、克林霉素、氯霉素、庆大霉素、四环素、利福平的耐药性均高于SCCmecⅡ型(P<0.05)。结论采用多重PCR技术检测150株临床分离的MRSA以SCCmecⅢ型为主,其次为SCCmecⅡ型,且两种SCCmec基因分型的耐药菌谱具有多样性。

Objective To analyze the drug resistance genotyping and drug susceptibility of methicillin-resistant staphylococcus aureus(MRSA)isolated from clinical practice.Methods A total of 254 strains of staphylococcus aureus(SA)isolated from various clinical specimens of inpatients and outpatients in Nanjing Gaochun People’s Hospital from March 2018 to July 2020 were selected.The mecA gene was detected by ordinary polymerase chain reaction(PCR).The MRSA isolates were genotyped using multiplex PCR technology for the staphylococcal chromosome mec box(SCCmec).Antimicrobial susceptibility test of SCCmec typeⅡand SCCmec typeⅢby kirby-Bauer(K-B)method.Results The results of Cefoxitin K-B showed that a total of 156 MRSA positive strains were detected in 254 SA strains,and the MRSA positive rate was 61.42%.The PCR amplification result of mecA gene showed that a total of 150 MRSA confirmed positive strains were detected out of 254 strains,and the detection rate was 59.06%.The results of multiplex PCR showed that among the 150 MRSA strains,39 were SCCmec typeⅡ,86 were SCCmec typeⅢ,two were SCCmecⅣa,two were SCCmecⅣb,and 21 were untyped.The resistance of SCCmecⅡand SCCmecⅢto Oxacillin,Ampicillin/Sulbactam,Cefoxitin,Meropenem,Penicillin G,and Cefazolin was 100.00%.SCCmecⅢwas resistant to Ciprofloxacin.The resistance of Erythromycin,Clindamycin,Chloramphenicol,Gentamicin,Tetracycline,and Rifampicin was higher than that of SCCmecⅡ(P<0.05).Conclusion Using multiplex PCR technology to detect 150 strains of clinically isolated MRSA are mainly SCCmec typeⅢ,followed by SCCmec typeⅡ,and the two SCCmec genotypes have a diverse spectrum of drug-resistant bacteria.