Companion animals have increased in most of the EU Countries and the high attention devoted to pet health and welfare leads to frequent use of antimicrobials. However, this practice may contributes to the diffusion of antimicrobial-resistance in the environment, posing risks to humans. The presence of canine faeces in urban settings, indeed, represents a concern for public health because they may contain antimicrobial-resistant pathogens that could easily spread in the environment and, perhaps, to humans. So, the aim of this study was to evaluate the presence of antimicrobial-resistant Salmonella spp. strains in dog faecal samples collected in urban parks within the city of Padua and Teramo.
Eighty faecal samples were tested to detect Salmonella spp. using the classical bacteriological procedure. Salmonella isolates were serotyped by the OIE Reference Laboratory for Salmonellosis (IZSVe, Italy). The antimicrobial susceptibility to different antimicrobial classes was evaluated by the disk diffusion method (CLSI). Salmonella strains were also screened for the presence of class 1 and 2 integrons and to a panel of antimicrobial-resistant genes usually located on mobile genetic elements. Salmonella spp. were detected in 2 (2.5%) (S. Veneziana and S. Bredeney respectively) of the faecal samples. Both the strains were multidrug-resistant, showing a lack or a reduce susceptibility to at least 3 of the antimicrobial classes tested. The two strains showed resistance especially to aminoglycosides, cephalosporins, sulphonamides and quinolones. Despite their phenotypic profile, none of the isolates carried class 1 or class 2 integrons or related antimicrobial-resistant genes.
Despite the low prevalence of Salmonella spp., these results highlight the role of pets as reservoir of potentially drug resistant pathogens. The sharing of the same environment confirms the possible transmission of antimicrobial-resistant bacteria from dogs to humans and viceversa. Therefore, the study stresses the need of surveilling this phenomenon also in companion animals.