摘要目的 研究上海不同级别医院下呼吸道标本中耐甲氧西林金黄色葡萄球菌(MRSA)的基因型及耐药性.方法 研究对象为2013年1月至2014年6月2家不同级别医院(瑞金医院及同仁医院)155例住院患者,男108例,女47例,平均年龄为(68±17)岁.收集患者下呼吸道痰液标本中分离的155株MRSA菌株,用PCR法对所有菌株进行多位点序列分型(MLST)和葡萄球菌A蛋白(Spa)分型,采用VITEK-32全自动微生物分析仪进行13种抗生素的体外药敏试验,并采用Fisher确切概率法进行统计学分析.结果 从155株MRSA菌株中共分离出28种MLST-spa分子克隆分型,其中ST764-t002(64株,41.3％)、ST239-t037(27株,17.4％)和ST239-t030(16株,10.3％)为主要型别.所有MRSA菌株对利奈唑胺、万古霉素、替考拉宁均敏感,敏感度均为100％,对磺胺甲噁唑/甲氧苄啶和利福平耐药度较低,敏感度分别为83.9％(130株)和83.2％(129株),但对青霉素、苯唑西林及头孢唑林显示高度耐药或全耐药,敏感度分别为0％(0株)、0％(0株)及3.9％(6株).ST239-t037型对磺胺甲噁唑/甲氧苄啶的耐药度高于其他型别,ST239-t030对利福平的耐药度高于其他型别,差异均有统计学意义(P＜0.001).155例患者平均住院时间为(97±84)d,78例(50.3％)患者有机械通气史,108例(69.7％)有侵袭性操作史,136例(87.1％)患者病程中使用过广谱抗生素.通过对2家医院患者的危险因素分析,年龄、住院天数、吸烟史、慢阻肺病史、机械通气及手术史比较差异有统计学意义(P＜0.05).结论 瑞金医院和同仁医院分离出的MRSA菌株多为多重耐药菌,共有28种MLST-spa克隆型,不同基因型的药敏试验谱有所差异.

abstractsObjective To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from lower respiratory tract at 2 different level hospitals in Shanghai.Methods The subjects included 155 patients at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014,including 108 males and 47 females,with a mean age of 67.8 ± 16.5.The 155 MRSA strains were isolated from lower respiratory tract specimens and multilocus sequence typing (MLST) and spa typing were analyzed by the PCR method.The antimicrobial resistance of MRSA was tested by VITEK-32.Fisher' s exact test was used for statistical analysis.Results Among the 155 strains,28 MLST-spa molecular types were identified,of which ST764-t002 (41.29％),ST239-t037 (17.42％) and ST239-t030 (10.32％) were the most predominant types.The MRSA strains were susceptible to linezolid,vancomycin and teicoplanin,and also had a lower resistance to trimethoprim-sulfamethoxazole and rifampin,with a susceptible rate of 83.9％ and 83.2％ respectively,but were highly resistant to other antibiotics.The resistance rate of ST239-t037 to trimethoprim-sulfamethoxazole was higher than that of other types,and the resistance rate of ST239-t030 to rifampin was higher than that of other types,the differences being significant(P ＜ 0.001).The mean length of hospital stay of the 155 patients was (97 ± 84) days,and mechanical ventilation were used in 78(50.3％) patients,while 108 (69.7％)) patients received invasive procedures.Broad-spectrum antibiotics were used in 136 (87.1％) patients.There were differences in age,hospitalization days,smoking history,history of COPD,mechanical ventilation,and operation between the 2 hospitals (P ＜ 0.05).Conclusion Most of the MRSA strains at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014 were multi-drug resistant,and the susceptibility spectrum of different genotypes was different.