Can Stray Cats Be Reservoirs of Antimicrobial Resistance?

SIMPLE SUMMARY: The spread of antimicrobial resistance is the main cause of failure in the treatment of infectious diseases. Antimicrobial resistance can transmit from host to host, even with low numbers of bacteria, and the exchange of antibiotic resistance genes can occur between bacteria in animals and humans. The role of animals as vectors and reservoirs of antimicrobial resistance is a growing global problem. Several studies have demonstrated the presence of antimicrobial resistance in companion and food-producing animals, but few in strays. In urban environments, stray cats are on the borderline between pets and strays and may play a role in the spread of antimicrobial resistance. In order to investigate the possible role of these animals, we evaluated antibiotic resistance and the presence of resistance genes of E. coli isolated from feces of stray cats. E. coli were resistant to beta-lactams and tetracyclines, two important classes of antibiotics, and harboured genes encoding these resistances. Although further investigation is needed, the presence of resistant E. coli confirms the hypothesis that stray cats may be faecal carriers of antibiotic resistance and the need to consider these animals in antimicrobial resistance monitoring programmes. ABSTRACT: The emergence and spread of antimicrobial resistance (AMR) is a global problem that requires a One Health approach. Despite several studies have reported the role of companion animals as reservoirs of AMR, limited information is available regarding the role of cats in the circulation of AMR. In this study, we evaluated the phenotypic and genotypic profile of 75 Escherichia coli isolated from rectal swabs and fecal samples of 75 stray cats (living in solitary or in a colony) sampled in Palermo (Sicily, Italy), to determine whether these animals may participate in the spread of AMR. Susceptibility to 8 antibiotics was tested using Minimum Inhibitory Concentration assays, while the presence of the common antibiotic resistance genes bla(TEM), bla(CTX-M), tet(A), and tet(B) was investigated by PCR. From the 75 E. coli isolates analyzed, 43% were resistant to at least one of the eight antibiotics tested, with 31% of the isolates resistant to ampicillin, 23% to cefotaxime, 21% to tetracycline, 20% to cefazolin, and 17% to amoxicillin/clavulanic acid. Most isolates harbored the bla(TEM) gene (29%), followed by bla(CTX-M) (23%), tet(A) (21%), and tet(B) (20%). Our results confirm the fecal carriage of antibiotic-resistant E. coli and clinically relevant resistance genes in stray cats. This study highlights the potential role of stray cats in the spread of AMR in urban environments, emphasising the need to better understand their role in AMR circulation when planning strategies to combat it.