耐氨基苷类高水平肠球菌医院感染的危险因素及氨基糖苷类耐药相关基因研究

目的 了解耐氨基糖苷类高水平肠球菌(HLAR)的耐药性和医院感染的危险因素,研究HLAR氨基糖苷类耐药相关基因类型分布.方法 采用全自动微生物鉴定仪VITEK-AMS对857株肠球菌属进行鉴定及抗菌药物敏感性检测；PCR法检测HLAR氨基糖苷类耐药相关基因,并对PCR结果进行测序分析.结果 肠球菌属中HLAR占50.4％,利奈唑胺、万古霉素和替考拉宁对HLAR的抗菌作用最好,但有3株屎肠球菌对万古霉素和替考拉宁耐药,粪肠球菌对氯霉素和四环素的耐药率高于屎肠球菌,而屎肠球菌对其他常用抗菌药物的耐药率明显高于粪肠球菌,粪肠球菌和屎肠球菌的耐药谱明显不同,aac(6')-Ie-aph(2〃)-Ia基因为耐庆大霉素高水平肠球菌(HLGR)的主要耐药基因,占HLGR的88.0％,严重的基础疾病、侵入性操作和头孢三代抗菌药物和激素的应用是肠球菌属医院感染的常见危险因素.结论 HLAR已成为医院感染的重要耐药菌,HLGR产生的主要机制是aac(6')-Ie-aph(2〃)-Ia基因介导对庆大霉素高水平耐药,控制常见医院感染危险因素,合理使用抗菌药物,可减少HLAR医院感染的发生.

Study on risk factors for nosocomial infections caused by high-level aminoglycoside-resistant Enterococcusand aminoglycoside resistance-related genes

OBJECTIVE To explore the antibiotic resistance and risk factors for nosocomial infections caused by high-level aminoglycoside-resistant(HLAR) Enterococcus,and investigate the genotypes related to high-level aminoglycoside resistance.METHODS A total of 857 strains of Enterococcus were identified and analyzed for their antimicrobial susceptibility by VITEK-AMS.The aminoglycoside resistance-related genes were detected by PCR.The sequencing analysis of PCR products was performed.RESULTS A total of 50.4% of Enterococcus isolates were HLAR Enterococcus.Linezolid,vancomycin and teicoplanin were mostly effective against HLAR Enterococcus,but there were three isolates resistant to vancomycin and teicoplanin.The resistance rates to chloramphenicol and tetracycline of E.faecium were higher than those of E.faecalis.The resistance rates to other antibiotics of E.faecalis were significantly higher than those of E.faecium.The drug resistance spectrum of E.faecalis was distinctly different from Enterococcus faecium.aac(6′)-Ie-aph(2″)-Ia gene was the major resistance gene in HLGR Enterococcus resistant to gentamicin,accounting for 88.0%.Serious underlying diseases,invasive procedure and use of the third-generation cephalosporin and hormones were the common risk factors for nosocomial infections caused by Enterococus.CONCLUSION HLAR Enterococcus have become the important resistant isolates causing nosocomial infections,and aac(6′)-Ie-aph(2″)-Ia-induced gentamicin resistance is the main resistance mechanism of HLGR Enterococcus;The control of common risk factors and rational use of antibiotics can reduce nosocomial infections caused by HLAR Enterococcus.