2株编码B类和D类碳青霉烯酶的鲍曼不动杆菌全基因组分析

Whole genome analysis of two strains of Acinetobacter baumannii encoding class B and Class D carbapenemases

目的基于全基因组测序技术解析2株同时产_(NDM-1)、_(OXA-23)、OXA-51碳青霉烯酶的鲍曼不动杆菌(Acinetobacter baumannii)的分子遗传特征,探究其耐药机制、进化路径及传播潜力,为制定临床感染控制策略提供数据支持。方法以2株来源于上海某2家医院ICU环境中的产B类和D类碳青霉烯酶的鲍曼不动杆菌为研究对象,利用二代测序技术获得菌株的全基因组序列。基于Proksee网站的GCskew和Prokka工具绘制菌株的全基因组图谱。通过药物敏感性实验和BacWGSTdb 2.0在线分析平台筛选耐药基因来分析菌株的耐药性,基于VFDB数据库、PubMLST数据库、OriTfinder、Kptive等工具进行毒力基因、MLST、荚膜血清型和质粒迁移性判断分析。采用邻接法绘制进化树。结果全基因组数据显示2株菌株均为ST164_Pasteur/ST1418_Oxford-KL47/OCL5型,均携带blaADC-25、blaCARB-5、bla_(CARB-16)、bla_(CARB-49)、bla_(NDM-1)、bla_(OXA-23)、bla_(OXA-91)7种耐药基因和不可移动型质粒,含有外膜蛋白、外排泵相关等45种毒力基因,和马来西亚及我国长沙、南昌、杭州的5株菌株亲缘性较近。结论上海市首次从医疗机构ICU环境中检出_(OXA-23)、OXA-51、_(NDM-1)共存的鲍曼不动杆菌株,或对公共卫生构成严重威胁,需加强对该类菌株的监测和研究,制定有效防控策略。

Objective To elucidate the molecular characteristics of two Acinetobacter baumannii strains producing_(NDM-1),_(OXA-23),and OXA-51 carbapenemases through whole genome sequencing technology,explore the mechanism of drug resistance,evolutionary pathways,and transmission potential,and provide data support for the formulation of clinical infection control strategies.Methods Two strains of Acinetobacter baumannii producing class B and class D carbapenemases,sourced from the ICU environment of two hospitals in Shanghai,were selected as study subjects.Next-generation sequencing technology was used to obtain the whole genome sequences of the strains.The whole genome map of the strains was drawn based on GCskew and Prokka tools on the Proksee website.Drug susceptibility experiments and BacWGSTdb 2.0 online analysis platform were used to screen for drug resistance genes to analyze the drug resistance of strains.Virulence genes,multilocus sequence typing(MLST),capsule serotype,and plasmid migration were evaluated based on the VFDB database,PubMLST database,OriTfinder,Kptive,and other tools,and an evolutionary tree was drawn by Neighbor-Joining method.Results Whole genome data showed that both strains belong to ST164_Pasteur/ST1418_Oxford-KL47/OCL5 type.All of them carry seven resistance genes(blaADC-25,blaCARB-5,bla_(CARB-16),bla_(CARB-49),bla_(NDM-1),bla_(OXA-23),bla_(OXA-91))and non-mobile plasmids.They possess 45 virulence genes related to outer membrane proteins and efflux pumps and are closely related to 5 strains from Malaysia and China(Changsha,Nanchang,and Hangzhou).Conclusions For the first time,the coexistence of_(OXA-23),OXA-51,_(NDM-1)producing Acinetobacter baumannii has been detected in the ICU environment in Shanghai,potentially posing a serious threat to public health.It is necessary to strengthen the monitoring and research of such strains to develop effective prevention and control strategies.