Fecal Carriage and Risk Factors Associated with Extended-Spectrum β-Lactamase-/AmpC-/Carbapenemase-Producing Escherichia coli in Dogs from Italy

MDR bacteria are an emerging global threat to public health, and the role of dogs in the rise of antimicrobial resistance is under investigation. This study investigated the fecal shedding of extended-spectrum β-lactamase (ESBL)-, AmpC- and carbapenemase (CP)-producing <i>Escherichia coli</i> and associated risk factors in dogs admitted to the Veterinary Teaching Hospital of Lodi, University of Milan, or other veterinary clinics and kennels in Northen Italy. Feces collected in 2020-2022 were microbiologically and molecularly analyzed. ESBL-/AmpC-/CP-producing <i>E. coli</i> was detected in 14/100 (14%) dogs. Eleven (11%), five (5%) and one (1%) dogs carried ESBL-, AmpC- and CP-producing <i>E. coli</i> phenotypes, respectively, supported by the PCR detection of <i>bla</i>_CTX-M and/or <i>bla</i>_TEM in ESBL-producing <i>E. coli</i>; <i>bla</i>_CMY-2 and the presence of putative low-level AmpC production in AmpC-producing <i>E. coli</i>; and <i>bla</i>_OXA-48 in CP-producing <i>E. coli</i>. Different combinations of resistance genes and genetic features were observed. Multidrug resistance was observed in 13/14 (92.9%) <i>E. coli</i> isolates. Binary logistic regression analysis showed that ESBL-/AmpC-/CP-producing <i>E. coli</i> fecal shedding tended to be associated with antibiotic treatment <i>(p</i> = 0.058; OR = 3.87). The detection of ESBL-/AmpC-producing <i>E. coli</i>, along with the presence of a carbapenemase-resistant <i>E. coli</i> isolate from domestic dogs, although still limited, emphasizes the need for antimicrobial stewardship and specific surveillance programs, particularly for CP-producing bacteria in companion animals.