Surveillance of Antimicrobial Resistance in Hospital Wastewater: Identification of Carbapenemase-Producing Klebsiella spp.

The objective of this study was to investigate the presence and persistence of carbapenemase-producing Klebsiella spp. isolated from wastewater and treated wastewater from two tertiary hospitals in Mexico. We conducted a descriptive cross-sectional study in two hospital wastewater treatment plants, which were sampled in February 2020. We obtained 30 Klebsiella spp. isolates. Bacterial identification was carried out by the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS ® ) and antimicrobial susceptibility profiles were performed using the VITEK2 ® automated system. The presence of carbapenem resistance genes (CRGs) in Klebsiella spp. isolates was confirmed by PCR. Molecular typing was determined by pulsed-field gel electrophoresis (PFGE). High rates of Klebsiella spp. resistance to cephalosporins and carbapenems (80%) were observed in isolates from treated wastewater from both hospitals. The molecular screening by PCR showed the presence of bla KPC and bla OXA-48-like genes. The PFGE pattern separated the Klebsiella isolates into 19 patterns (A-R) with three subtypes (C1, D1, and I1). Microbiological surveillance and identification of resistance genes of clinically important pathogens in hospital wastewater can be a general screening method for early determination of under-detected antimicrobial resistance profiles in hospitals and early warning of outbreaks and difficult-to-treat infections.