Isolation of Multiresistant Bacterial Strains from Dairy Wastewater: A Public Health Concern in a One Health Perspective

The use of antibiotics in the veterinary and zootechnic sectors poses a challenge to the reduction in antibiotic resistance rates. We evaluated the presence of antibiotic-resistant bacteria in the wastewater of dairy farms in the Sicily Region, Italy. The samples were examined by isolating and identifying the bacterial strains, which were then tested for the main classes of antibiotics. Aeromonas spp. and Vibrio spp. were the more commonly isolated strains (18.2%), followed by Pseudomonas spp. (15.9%), Enterobacter spp. and Citrobacter spp. (13.6%). Macrolides were the drugs against which the highest resistance was detected, followed by tetracyclines, penicillins, and cephalosporins. The agri-food chain and zootechnic areas embody an important source of bacteria resistant to antibiotics, and their presence in wastewater from processing factories could play a pivotal role in spreading these microorganisms and in environmental contamination.