Wild Micromammals as Bioindicators of Antibiotic Resistance in Ecopathology in Northern Italy

SIMPLE SUMMARY: In recent years, animal and human health have been linked in a “One Health” approach. Wildlife could act as a reservoir for different antibiotic-resistant pathogens, representing an issue for human and domestic animal health. The aim of this study was to evaluate the presence and circulation of antimicrobial-resistant bacterial species in wild micromammals in the province of Parma, Northern Italy. Multi-drug-resistant strains and a high prevalence of resistance to critically important antibiotics were detected. Furthermore, resistance to commonly used antibiotics was detected in a large percentage of isolates. Considering that micromammals are good bioindicators, obtained results highlighted a high prevalence of strains resistant to antimicrobials of critical importance for human and animals in the investigated areas, thus representing a public health hazard. ABSTRACT: Antimicrobial resistance (AMR) is an increasing threat to human health and an important issue also in the natural environment. For this study, an ecopathological approach was applied to the monitoring of the antimicrobial resistance in the province of Parma, Northern Italy. Fourteen monitoring sites and seventy-four faecal samples from four species of wild micromammals (Apodemus sylvaticus, Microtus savii, Mus domesticus and Suncus etruscus) were collected. Samples were subjected to bacteriological examination and antimicrobial susceptibility testing. Antibiotics belonging to 13 different antibiotic classes were tested. Collected data showed a prevalence of multi-drug resistant (MDR) strains of 55.13% and significant differences in the prevalence of MDR strains among the different micromammal species, while sex, age and anthropization level did not significantly affected MDR strains prevalence. Moreover, a high prevalence of bacterial strains resistant to colistin (95%), gentamicin (87%) and amikacin (83%) was observed. To our knowledge, this is the first report on antibiotic resistance in wild micromammals in the province of Parma.