Detection and characterization of multidrug-resistant Klebsiella spp. and Enterobacter spp. isolates in Colombian guinea pigs intended for human consumption.

Background and Aim: Antimicrobial resistance (AMR) has emerged as a global health threat, with food-producing animals recognized as reservoirs of multidrug-resistant (MDR) bacteria. Guinea pigs (Cavia porcellus), traditionally consumed in several Andean regions, remain underexplored in terms of food safety risks. This study aimed to detect, characterize, and analyze the AMR patterns and resistance genes of Klebsiella spp. and Enterobacter spp. isolated from slaughtered guinea pigs intended for human consumption in Colombia. Materials and Methods: A cross-sectional descriptive study was conducted on 70 guinea pigs with macroscopic intestinal lesions. Intestinal swabs were cultured on blood and MacConkey agar, and isolates were identified using biochemical tests and 16S ribosomal RNA sequencing. Antimicrobial susceptibility testing was performed against nine antibiotics representing seven antimicrobial classes, using Clinical and Laboratory Standards Institute standards. MDR was defined as resistance to ≥1 antibiotic in ≥3 classes. Polymerase chain reaction assays were employed to detect resistance genes, including β-lactamase Klebsiella pneumoniae carbapenemase (blaKPC ), class d β-lactamase oxacillinase-48 gene (blaOXA-48 ), ampC-lactamase (ampC), and New Delhi metallo-beta-lactamase 1 (blaNDM-1 ). Results: Ten isolates were obtained, comprising Klebsiella spp. (70%) and Enterobacter hormaechei (30%). All isolates (100%) exhibited MDR profiles. High resistance rates were observed against fluoroquinolones (100%), beta-lactams (90%), aminoglycosides (70%), carbapenems (70%), and cephalosporins (70%), whereas resistance to trimethoprim-sulfamethoxazole was 40%. Molecular analysis revealed the presence of blaKPC in seven isolates, blaOXA-48 in two, and ampC in three. No blaNDM-1 genes were detected. Notably, E. hormaechei isolates demonstrated broader resistance spectra than Klebsiella. Conclusion: This study provides the first evidence in Colombia of MDR Klebsiella spp. and Enterobacter spp. isolates carrying clinically important resistance genes in guinea pigs intended for human consumption. The detection of carbapenemase genes (blaKPC and blaOXA-48 ) is particularly concerning given their role in limiting therapeutic options. These findings highlight the urgent need for improved antimicrobial stewardship, stricter regulation of antibiotic use in guinea pig production systems, enhanced surveillance, and targeted farmer education to mitigate AMR risks at the human-animal interface.