mazEF基因在肠球菌中的分布及与耐药的相关性研究

Study on the distribution of mazEF gene in enterococci and its relationship with drug resistance

目的研究mazEF基因在肠球菌临床分离株的分布特征,并探讨其与肠球菌耐药的相关性。方法收集包头地区2013年1月—2016年12月临床来源的肠球菌187株,随机选出90株作为实验菌株,采用聚合酶链反应(PCR)法及基因测序技术检测mazEF基因,VITEK-2 Compact全自动微生物鉴定及药敏系统鉴定肠球菌并同步测定10种抗菌药物(氨苄西林、青霉素、四环素、替加环素、左氧氟沙星、环丙沙星、万古霉素、利奈唑胺、高水平庆大霉素和红霉素)最低抑菌浓度(minimal inhibititory concentration,MIC),分析mazEF基因在肠球菌基因组中的分布及与耐药之间的关联。结果 90株肠球菌属,mazEF基因在肠球菌属基因组的阳性率为86.7%。在对氨苄西林、左氧氟沙星、青霉素、四环素、高水平庆大霉素、红霉素、环丙沙星和万古霉素耐药的肠球菌中,mazEF基因阳性率分别为88.7%、86.2%、89.1%、84.6%、81.5%、85.0%、89.4%和60.0%,敏感的肠球菌中,mazEF基因阳性率分别83.7%、87.5%、82.6%、92.0%、94.4%、100.0%、87.1%和88.2%,耐药株和敏感株中,mazEF基因阳性率无统计学差异(P>0.01)。结论 mazEF基因在肠球菌基因组中分布的阳性率为86.7%(78/90),其分布与对氨苄西林、左氧氟沙星、青霉素、四环素、高水平庆大霉素、红霉素和环丙沙星耐药无显著相关性,与天然耐万古霉素也无显著相关性。

Objective To study the distribution of mazEF gene in the clinical isolates of Enterococci and its relationship with drug resistance. Methods A total of 187 clinical isolates of enterococci were collected in Baotou from January 2013 to December 2016. 90 were selected for ftarther detections and determinations of the distribution of mazEF gene using PCR and gene sequencing methods. The isolates were identified as enterococci by conventional biochemical tests and VITEK 2 Compact. The antimicrobial susceptibility of the isolates was determined using VITEK 2 Compact. Results The mazEF gene was found is 86.7% of the genomes in enterococcal isolates. The positive rate of mazEF gene in the susceptible strains against ampicillin, levofloxacin, penicillin, tetracycline, highlevel gentamicin, erythromycin, ciprofloxacin, and vancomycin were 83.7%, 87.5%, 82.6%, 92.0%, 94.4%, 100.0%, 87.1%, and 88.2%, respectively. The positive rate of mazEF gene in the resistant strains against the eight antibacterials mentioned above were 88.7%, 86.2%, 89.1%, 84.6%, 81.5%, 85.0%, 89.4%, and 60.0%, respectively. Conclusion There were no significant correlations between the distribution of mazEF gene and resistance against ampicillin, levofloxacin, penicillin, tetracycline, high-level gentamicin, erythromycin, ciprofloxacin, and innate vancomycin.