Carbapenem-resistant bacteria pose a serious worldwide public health problem, and growing evidence suggests that companion animals may contribute to the expansion of antimicrobial resistance. This research assessed the intestinal presence of Escherichia coli producing extended-spectrum β-lactamase (ESBL), AmpC, and carbapenemase (CP) enzymes, along with possible associated factors, in both healthy and diseased stray cats admitted to the Veterinary Teaching Hospital of Lodi, University of Milan, Italy. Fecal material gathered between 2020 and 2022 underwent both microbiological and molecular testing. Overall, 18 of 94 (19.1%) cats carried E. coli producing ESBL, AmpC, or CP. Specifically, ESBL-, AmpC-, and CP-type E. coli were identified in 12 (12.8%), 4 (4.3%), and 7 (7.4%) cats, respectively. Genetic screening confirmed blaCTX-M in all ESBL isolates, blaCMY-2 in every AmpC isolate, and either blaNDM (4/7; 57.1%) or blaOXA-48 (3/7; 42.9%) among the CP group. Some isolates showed overlapping gene and resistance patterns. Minimum inhibitory concentration (MIC) testing revealed all isolates were multidrug resistant. Significant predictors of ESBL-, AmpC-, and/or CP-positive E. coli carriage included hospitalization (P < 0.0001), antimicrobial administration during hospitalization (P < 0.0001), and poor clinical condition (P < 0.0001). The occurrence of CP-producing E. coli in stray cats is alarming and underscores the need for ongoing monitoring of CP-producing Enterobacteriaceae and for rational antibiotic use to limit resistant bacterial spread. Given the study’s constraints, a One Health strategy is recommended to further explore whole-genome profiles and AMR epidemiology in stray cats, including other bacterial species and environmental sources.
