耐甲氧西林金黄色葡萄球菌耐药性及SCCmec基因分型研究

Drug resistance and SCCmec typing of methicillin-resistant staphylococcus aureus

目的分析耐甲氧西林金黄色葡萄球菌(MRSA)耐药性及SCCmec基因分型,探讨临沂市人民医院MRSA菌株的流行趋势,为临床预防和有效治疗MRSA感染提供理论依据。方法选取2018年2月-10月临沂市人民医院门诊及住院患者的各类送检标本,从中分离得到MRSA菌株47株,剔除同一患者多次分离得到的菌株,仅留取第1次分离的菌株,采用VITEK-2 Compact全自动微生物分析仪对收集的菌株进行细菌鉴定和药敏试验。采用聚合酶链反应对SCCmec基因分型进行研究。结果 47株MRSA分离菌株中SCCmecⅡ型9株(19.15%),SCCmecⅣa型35株(74.47%),另有3株未分型(6.38%)。MRSA分离菌株对青霉素、苯唑西林及头孢西丁等β-内酰胺类抗菌药物全部耐药,对奎奴普汀/达福普汀、利奈唑胺、万古霉素、替加环素、呋喃妥因、利福平及庆大霉素敏感率为100%;SCCmecⅡ型对环丙沙星、左氧氟沙星及莫西沙星的耐药率高于SCCmecⅣa型(P<0.05)。SCCmecⅣa型对红霉素、克林霉素耐药率高于SCCmecⅡ型(P>0.05)。结论分离的MRSA菌株以SCCmecⅣa型为主,不同SCCmec基因型的耐药谱有差异,临床医生应根据药敏结果合理使用抗菌药物。

Objective To analyze the resistance and SCCmec genotyping of methicillin-resistant staphylococcus aureus(MRSA), to explore the epidemic trend of MRSA strains in this area, and to provide theoretical scientific basis for clinical prevention and effective treatment of MRSA infection. Methods A total of 47 strains of MRSA isolated from the outpatients and inpatients of the hospital from February to October 2018 were collected. The strains isolated from the same patient were removed, and only the first isolates were selected. VITEK-2 compact automatic microorganisms were used. The analyzer performs bacterial identification and drug susceptibility testing on the collected strains. SCCmec genotyping studies were performed using multiplex polymerase chain(PCR) reactions. Results Among the 47 isolates of MRSA, 9 strains(19.15%) were SCCmec II, 35 strains(74.47%) were SCCmec IVa, and 3 were not classified(6.38%). MRSA isolates are resistant to β-lactam antibiotics such as penicillin, oxacillin, and cefoxitin. For quinopontin/dafoptin, linezolid, vancomycin, tigecycline, nitrofurantoin, rifampicin and gentamicin, the sensitivity rates were 100%;the resistance rate of SCCmec II MRSA strain to ciprofloxacin, levofloxacin, moxifloxacin, trimethoprim/sulfamethoxa-zole and tetracycline was higher than that of SCCmec IVa MRSA strain(P < 0.05);the MRSA strain was severely resistant to erythromycin and clindamycin, and the resistance of SCCmec IVa type was higher than the SCCmec type II. The difference was not statistically significant(P > 0.05). Conclusions The MRSA strain isolated from Linyi People’s Hospital is mainly SCCmec IVa. The resistance spectrum of different SCCmec types is different, and clinicians should use antibiotics reasonably according to drug sensitivity results.