Molecular epidemiology of carbapenem-resistant Escherichia coli in a tertiary hospital located in the Dabie Mountains region, China

Abstract

Abstract Objective: The objective of this study was to conduct a molecular epidemiological study of carbapenem-resistant Escherichia coli (CREco) within a tertiary hospital situated in the Dabie Mountains region of China, while also elucidating the underlying mechanisms of antimicrobial resistance. Patients and methods: Between 2018 and 2022, a total of 33 CREco isolates were isolated from 33 patients in a tertiary hospital situated in the Dabie Mountains region of China. Subsequently, the next-generation sequencing of CREco isolates was performed, and the clinical retrospective analysis and the comprehensive bioinformatic analysis were presented. Phenotypic identification of carbapenemase and AmpC-type β-lactamase were also conducted. Results: Two kinds of carbapenemase genes blaNDM (n = 30) and blaKPC-2 (n = 2) were identified in 33 CREco isolates. Of blaNDM-positive isolates, 24 belonged to blaNDM-5, and the remaining were blaNDM-13 (n = 4), blaNDM-1 (n = 1), and blaNDM-6 (n = 1). The predominant STs of these isolates were ST410 (13.3%, 4/30), ST692 (10.0%, 3/30), and ST156 (10.0%, 3/30). Except for carbapenemase genes, the most prevalent resistance genes were sulfonamide (97%, 32/33), and aminoglycoside (94%, 31/33) genes. By the disserted annotation of the core genetic envirionment of blaNDM and blaKPC, we identified that blaNDM and blaKPC were harbored by Tn125 and Tn6296, respectively. Although the core genetic environment of them were conserved, but the different truncations were underwent in the upstream/downstream of the prototype of Tn125 and Tn6296. Conclusion: The blaNDM-5 was the principal carbapenem resistance mechanism of CREco isolates in the Dabie Mountains region in China. Besides, two rare NDM variants blaNDM-6 and blaNDM-13 were detected herein, and the dissemination risk of these two genes was needed to be attention and the further surveillance was needed in China.