广州市某医院2021-2023年临床分离耐碳青霉烯大肠埃希菌的流行病学特征

Epidemiological characterizations of carbapenem-resistant Escherichia coli isolates from a hospital in Guangzhou,2021-2023

目的探讨广州市某医院2021—2023年临床分离的耐碳青霉烯大肠埃希菌(carbapenem-resistant Escherichia coli,CREC)的流行病学特征,为CREC感染的防控提供科学依据。方法收集2021—2023年该院分离的非重复CREC菌株,分析其临床特征。随机挑选42株进行物种鉴定、抗微生物药物敏感性试验和多位点序列分型。通过全基因组测序及生物信息学分析,探究CREC携带的耐药基因、毒力基因、复制子及碳青霉烯耐药基因所在质粒类型。结果2021—2023年该院共分离大肠埃希菌(Escherichia coli,EC)2887株,其中CREC 105株。3年间CREC的检出率分别为1.76%、2.80%和5.69%,呈显著上升趋势(P<0.001)。该院CREC对多种抗生素耐药,其中阿莫西林-克拉维酸、头孢他啶和头孢吡肟的耐药率均为100.00%,厄他培南和亚胺培南的耐药率为97.62%,左氧氟沙星为83.33%,阿米卡星为45.24%。所有CREC分离株均对替加环素敏感。42株CREC分为14种ST型,主要的ST型为ST167(28.57%)、ST410(26.19%)和ST131(9.52%)。ST410型CREC携带的fim、algA、icsP/sopA和高致病性毒力岛(high-pathogenicity island,HPI)相关毒力基因显著高于ST167型CREC(P<0.05),而aslA、hcp-2显著低于ST167(P<0.05)。该院CREC携带的碳青霉烯耐药基因主要为bla_(NDM-5)(n=34),其次是bla_(NDM-1)(n=6),仅有1株携带bla_(KPC-2),上述耐药基因主要位于IncF(n=27)和IncX3(n=11)型质粒。结论2021—2023年该院CREC检出率显著上升,以ST167和ST410型为主。ST410型CREC是一种新流行的高危克隆,携带了黏附、生物膜形成和HPI相关毒力基因,亟需监测其流行现状和传播特征,为防控措施的制定提供依据。

Objective To investigate the epidemiology and genomic characterizations of carbapenem-resistant Escherichia coli(CREC)from a tertiary hospital in Guangzhou,Guangdong province,China from January 2021 to December 2023.Methods The non-repetitive CREC isolates identified at the hospital from January 2021 to December 2023 were included and their clinical characteristics were analyzed through the clinical record system.A total of 42 CREC isolates were randomly selected for species identification,antimicrobial susceptibility testing,and multilocus sequence typing.Wholegenome sequencing and bioinformatics analysis were conducted to investigate the antimicrobial resistance genes,virulencerelated genes,replicons,and plasmid types carrying the carbapenem resistance genes in CREC.Results A total of 2887 Escherichia coli(EC)isolates were collected from the hospital between January 2021 to December 2023,including 105 CREC strains.The prevalence rates of CREC over the three years were 1.76%,2.80%,and 5.69%,respectively,showing a significant upward trend(P<0.001).All 42 CREC isolates showed resistance to multiple antibiotics,with resistance rates for amoxicillin-clavulanate,ceftazidime,and cefepime all at 100.00%,ertapenem and imipenem at 97.62%,levofloxacin at 83.33%,and amikacin at 45.24%.All CREC isolates were susceptible to tigecycline.The 42 CREC strains were classified into 14 ST types,with the main types being ST167(28.57%),ST410(26.19%),and ST131(9.52%).ST410 CREC isolates carried significantly more fim,algA,icsP/sopA,and high-pathogenicity island(HPI)related virulence genes than ST167 isolates(P<0.05),whereas aslA and hcp-2 were significantly lower than ST167(P<0.05).The carbapenem resistance genes carried by CREC were primarily bla_(NDM-5)(n=34),followed by bla_(NDM-1)(n=6),with only one isolate carrying bla_(KPC-2).These carbapenem resistance genes were mainly located on IncF(n=27)and IncX3(n=11)type of plasmids.Conclusions The prevalence of CREC significantly increased from 2021 to 2023 in this hospital,with ST167 and ST410 as the dominant types.ST410 CREC is a newly prevalent high-risk clone carrying adhesion,biofilm formation,and HPI-related virulence genes,and there is an urgent need to monitor its epidemiological status and transmission characteristics to provide a basis for the formulation of control measures.