Detection of carbapenemases in Enterobacterales and other Gram-negative bacilli recovered from hospital and municipal wastewater in Mexico City.

Wastewater serves as a reservoir for antimicrobial-resistant bacteria. This study revealed the presence of carbapenem-resistant and carbapenemase-producing Gram-negative bacilli (GNB), established clonal relationships among isolates in hospital and municipal wastewater, and identified a high-risk clone in municipal wastewater. A total of 63 isolates of GNB were obtained, with Enterobacterales being the most frequently isolated group (62%). Carbapenemase-producing Lelliottia amnigena, Kluyvera cryocrescens, and Shewanella putrefaciens isolates were documented for the first time in Mexico. The detectableted carbapenemase genes were blaKPC (55%), blaNDM (12%), blaVIM-2 (12%), blaOXA-48 (4%), blaGES (2%), blaNDM-1 (2%), and blaNDM-5 (2%). Clonal relationships were observed among Klebsiella pneumoniae and Enterobacter spp. isolates, and remarkably the high-risk clone Escherichia coli ST361, carrying blaNDM-5, was identified. This study demonstrates that wastewater harbours carbapenem-resistant and carbapenemase-producing bacteria, posing a public health threat that requires epidemiological surveillance.