Molecular epidemiological characteristics and drug resistance of carbapenem-resistant Enterobacterales

Abstract:

Objective To investigate the molecular epidemiological characteristics of carbapenem-resistant Entero-bacterales (CRE), study drug resistance characteristics and homology of CRE. Methods 158 strains of non-repetitive CRE isolated from a hospital in Ningxia from January 2018 to May 2021 were collected, drug resistance genes were detected by polymerase chain reaction (PCR), phenotypic confirmation was conducted by modified carbapenem inactivation method (mCIM) combined with EDTA-modified carbapenem inactivation method (eCIM), horizontal transfer of bla_NDM was analyzed by plasmid conjugation test, homology analysis was performed by multilocus sequence typing (MLST). Results 158 CRE strains were mainly Klebsiella pneumoniae (61 strains, 38.61%), followed by Enterobacter cloacae (37 strains, 23.42%) and Escherichia coli (23 strains, 14.56%), the departments with most detected CRE were intensive care unit as well as burn and plastic surgery department. The top four specimen sources of CRE strains were sputum, purulent secretions, drainage fluid and sterile midstream urine respectively, the detected drug-resistant gene was mainly New Delhi metallo-β-lactamase (NDM). Positive rate of 23 strains of Escherichia coli mCIM combined with eCIM test was 95.65%, plasmid conjugation test successfully transferred bla_NDM gene of 15 strains from 20 Escherichia coli to Escherichia coli J53AZ^R, resistance of the conjugated strains to imipenem, meropenem and cephalosporins was stronger than that of the recipient strains. Fourteen ST types were detected from 23 strains of Escherichia coli by multi-locus sequence typing (MLST), mainly ST10 and ST410. Conclusion CRE strains in the hospital mostly come from ICU, mainly carrying bla_NDM resistance gene, and have high resistance to commonly used antimicrobial agents in clinic, hospital should strengthen the supervision of antibiotics use and guide the rational drug use in clinical practice. NDM enzyme subtypes in this region gradually change, thus continuous monitoring should be carried out to find new subtypes in time.