Objective: To analyze the epidemiological characteristics of drug resistance genes of carbapenemase-producing Escherichia coli (CPECO) in Henan Province Hospital of Traditional Chinese Medicine from 2021 to 2023, providing data support and theoretical basis for controlling nosocomial infections of CPECO. Methods: Using a cross-sectional study, 30 carbapenem-resistant Escherichia coli (CRECO) strains confirmed by VITEK-2 Compact identification and drug sensitivity test in the Clinical Microbiology Laboratory of Henan Province Hospital of Traditional Chinese Medicine from 2021 to 2023 were tested, using carbapenemase inhibitor enhancement test to conduct preliminary screening of carbapenemases, and colloidal gold immunochromatography and polymerase chain reaction (PCR) were used to determine the phenotypes and genotypes of common carbapenemases (blaKPC, blaNDM, blaVIM, blaIMP, blaOXA) respectively, and the genotypes (blaSHV, blaTEM, blaCTX) of common extended Spectrum beta-lactamases (ESBL) were confirmed using PCR. The PCR amplification products of carbapenemase and ESBL positive strains were Sanger-sequenced, and the sequencing products were compared on the Blast website to determine the exact carbapenemase and ESBL genotypes. Sequence typing (ST) was performed on CPECO using the Achtman multi-locus sequence typing scheme to determine the cloning relationship between different strains. Results: A total of 21 CPECO strains were screened. Drug sensitivity test results showed that CPECO strains showed widespread drug resistance, with the resistance rate to monocyclic (aztreonam) and trimethoprim/sulfamethoxazole being over 60%(16/21, 14/21), and the resistance rate to other antibacterial drugs being 100%. Only the sensitivity to aminoglycosides and fosfomycin remained relatively high, and no strains resistant to tigecycline and colistin were found. Colloidal gold immunochromatography detected 18 blaNDM types, 2 blaKPC types, and 1 blaIMP type. Sequencing of drug resistance gene PCR products classified 17 blaNDM-5 strains, 1 blaNDM-4 strain, 2 blaKPC-2 strain, and 1 blaIMP-4 strain, which were completely consistent with the results of screening test and colloidal gold immunochromatography. ESBL resistance gene testing showed that the detection rate of blaTEM was 42.9%(9/21), blaCTX-M was 33.3%(7/21), and blaSHV was 4.8%(1/21). The rate of blaNDM producing CPECO carrying both ESBL resistance genes was 27.8%(5/18). The MLST typing results revealed 11 sequence types (STs), including one ST155 clonal complex and nine singleton STs. Among these, there were seven strains of ST167, five strains of ST410, and one strain each of ST58, ST68, ST69, ST93, ST131, ST155, ST648, ST1114, and ST3268. Conclusion: The main resistance mechanism identified in this study for CPECO was the production of blaNDM-5 carbapenemase, with a high proportion of strains also carrying blaTEM-1D and/or blaCTX-M-15 ESBLs. MLST typing found that the epidemic strain of CPECO showed certain polymorphism, but there were clonal transmission of multiple clonal complexes between ST167 and ST410.
目的： 对2021—2023年河南省某医院产碳青霉烯酶大肠埃希菌（Carbapenemase-prodcing Escherichia coli，CPECO）的耐药基因流行特征进行分析，为控制CPECO的院内传播感染提供数据支撑和理论依据。 方法： 采用横断面研究，对2021—2023年河南省中医院临床微生物实验室经VITEK-2 Compact鉴定和药敏试验确认的30株碳青霉烯耐药的大肠埃希菌（CRECO），使用碳青霉烯酶抑制剂增强试验进行碳青霉烯酶初筛，胶体金免疫层析法和聚合酶链反应（PCR）法分别对常见碳青霉烯酶表型和基因型（blaKPC、blaNDM、blaVIM、blaIMP、blaOXA）进行确证，同时使用PCR法对常见超广谱β-内酰胺酶（ESBL）基因型（blaSHV、blaTEM、blaCTX）予以确证；对碳青霉烯酶和ESBL阳性菌株的PCR扩增产物进行Sanger测序，测序产物在Blast网站中进行比对，确定确切的碳青霉烯酶和ESBL基因型；采用Achtman多位点序列分型方案对CPECO进行序列分型（ST），确定不同菌株之间的克隆关系。 结果： 共筛选出CPECO 21株；药敏试验结果显示，CPECO菌株呈现泛耐药性，对单环类（氨曲南）和甲氧苄啶/磺胺甲噁唑的耐药率在60%以上（16/21、14/21），其余抗菌药物的耐药率为100%。仅对氨基糖苷类药物和磷霉素保持相对较高的敏感性，未发现对替加环素和多黏菌素耐药的菌株。胶体金免疫层析法检出blaNDM型18株，blaKPC型2株，blaIMP型1株；耐药基因PCR产物测序分型blaNDM-5型17株，blaNDM-4型1株，blaKPC-2型2株，blaIMP-4型1株，与筛选试验和胶体金免疫层析法结果完全吻合。ESBL耐药基因检测显示，blaTEM检出率为42.9%（9/21），blaCTX-M为33.3%（7/21），blaSHV为4.8%（1/21），产blaNDM型CPECO同时携带两种ESBL耐药基因的比率为27.8%（5/18）；MLST分型结果发现11种ST型，包括1个ST155复合群和9个独立型，其中ST167型7株，ST410型5株，ST58、ST68、ST69、ST93、ST131、ST155、ST648、ST1114和ST3268各1株。 结论： 本研究CPECO主要耐药机制为产blaNDM-5型碳青霉烯酶，同时携带blaTEM-1D型和（或）blaCTX-M-15型ESBL比例较高。MLST分型发现，CPECO的流行株呈现一定的多态性，但 ST167和ST410存在多个克隆复合群的克隆性传播。.