呼吸内科住院患者MRSA感染特点及其基因多态性

Characteristics of MRSA infection in hospitalized patients of respiratory medicine department and gene polymorphisms

目的分析呼吸内科住院患者耐甲氧西林金黄色葡萄球菌(MRSA)感染特点及其基因多态性分型情况。方法选择海南医学院第一附属医院呼吸内科2018年9月-2020年3月金黄色葡萄球菌感染的92例住院患者,鉴定MRSA并分析药敏试验结果。选取未发生任何病原菌感染的166例患者为对照组,以Logistic回归法分析MRSA的易感因素。采取聚合酶链式反应(PCR)鉴定MRSA基因,采取随机扩增多态性DNA技术(RAPD)确定基因分型。结果92例金黄色葡萄球菌感染患者30例为MRSA感染,占32.61%,感染部位主要为呼吸道23例,占76.67%。单因素分析显示,MRSA感染患者中年龄≥60岁、住院时间≥14 d、使用激素、使用免疫抑制剂、无创机械通气、气管插管、气管切开、留置导尿、静脉置管、合并糖尿病、合并基础肺疾病的比例高于对照组患者,差异有统计学意义(P<0.05),Logistic回归分析结果显示:气管插管、留置导尿、合并糖尿病是发生MRSA感染的危险因素(P<0.05)。MRSA对β-内酰胺类100%耐药,对万古霉素、替考拉宁、利奈唑胺100%敏感。MRSA基因分型分为15个基因型:Ⅰ型3株、Ⅳ型3株、Ⅴ型6株、Ⅵ型4株、Ⅷ型2株、Ⅸ型2株、ⅩⅢ型2株,其余基因型各1株。结论呼吸内科住院患者自身基础疾病和侵入性操作是发生MRSA的易感因素;MRSA对绝大多数抗菌药物耐药,临床治疗宜首选万古霉素;MRSA基因多态性分型可为MRSA流行病学防治提供参考。

OBJECTIVE To analyze the characteristics of methicillin-resistant Staphylococcus aureus(MRSA)infection in hospitalized patients of respiratory medicine department and observe the gene polymorphisms.METHODS A total of 92 patients with S.aureus infection who were hospitalized in respiratory medicine department of the First Affiliated Hospital of Hainan Medical College from Sep 2018 to Mar 2020 were enrolled in the study,the MRSA strains were identified,and the drug susceptibility testing was performed.166 patients without infection were set as the control group,and logistic regression analysis was carried out for predisposing factors for the MRSA infection.MRSA genes were identified by using polymerase chain reaction(PCR),and the genotypes were determined by means of random amplified polymorphic DNA(RAPD)technique.RESULTS Among the 92 patients with S.aureus infection,30 had MRSA infection,accounting for 32.61%;23 had respiratory tract infection,accounting for 76.67%.Univariate analysis showed that the proportions of the MRSA infection patients with no less than 60 years of age,length of hospital stay no less than 14 days,use of hormones,use of immunosuppressors,non-invasive mechanical ventilation,endotracheal intubation,tracheotomy,urinary catheter indwelling,intravenous catheterization,diabetes mellitus,and underlying pulmonary diseases were significantly higher than those of the patients in the control group(P<0.05).Logistic regression analysis showed that endotracheal intubation,urinary catheter indwelling and diabetes mellitus were the risk factors for the MRSA infection(P<0.05).The drug resistance rate of the MRSA strains toβ-lactams was 100%,the drug susceptibility rates to vancomycin,teicoplanin and linezolid were 100%.There were 15 genotypes that were identified in the MRSA strains:3 strains of typeⅠ,3 strains of typeⅣ,6 strains of typeⅤ,4 strains of typeⅥ,2 strains of typeⅧ,2 strains of typeⅨ,2 strains of typeⅩⅢ,1 of each of the rest genotypes.CONCLUSION The underlying diseases and invasive procedures are the predisposing factors for the MRSA infection in the hospitalized patients of respiratory medicine department.The MRSA strains are resistant to most of antibiotics,and vancomycin is preferred for clinical treatment.The gene polymorphisms of MRSA strains may provide guidance for epidemiologic prevention and control of the MRSA infection.