Genomic characterization of carbapenemase-producing Enterobacterales from Dhaka food markets unveils the spread of high-risk antimicrobial-resistant clones and plasmids co-carrying bla NDM and mcr-1.1.

Background: The transmission of carbapenemase-producing Enterobacterales (CPE) in the external environment, especially through food, presents a significant public health risk.

Objectives: To investigate the prevalence and genetic characteristics of CPE in food markets of Dhaka, Bangladesh, using WGS.

Methods: CPE isolates were obtained from different food and water samples collected from food markets in the southern part of Dhaka, Bangladesh. The isolates subsequently underwent molecular typing, WGS employing both short- and long-read sequencers, and plasmid analysis.

Results: This study unveiled an extensive spread of CPE, with no significant difference in contamination rates observed in samples (N = 136), including meat (n = 8), fish (n = 5), vegetables (n = 36) or various food-washed water (n = 65) from markets near hospitals or residential areas. Thirty-eight Enterobacterales from 33 samples carried carbapenemase genes (bla _{NDM-1, -4, -7}, bla _KPC-2, bla _OXA-181 or bla _IMI-1). Among these, the high-risk Escherichia coli ST410 clone was the most prevalent and distributed across various locations. Furthermore, the identification of IncHI2 plasmids co-harbouring resistance genes like bla _NDM-5 and mcr-1.1, without discernible epidemiological connections, is a unique finding, suggesting their widespread dissemination.

Conclusions: The analysis unveils a dynamic landscape of CPE dissemination in food markets, underscored by the proliferation of novel IncHI2 hybrid plasmids carrying both colistin- and carbapenem-resistance genes. This illuminates the ever-evolving landscape of antimicrobial resistance in Dhaka, urging us to confront its emergent challenges.