Bovine and Pig Carcasses as a Source of in Poland: A Reservoir for Antimicrobial-Resistant .

is one of the most common causes of foodborne bacterial infections worldwide. Why poultry has been shown to be one of the most significant sources of these bacteria, ruminants, especially cattle, are also responsible for a high number of human , and to a lesser extent , infections. In this study, bovine and pig carcasses in Poland were investigated for the presence of and for their antimicrobial resistance. A total of 204 swabs from bovine carcasses and 355 swab samples from pig carcasses were tested during 2014-2018. was identified in 129 (36.3%) of the pig and in 11 (5.4%) of the bovine carcasses, respectively. The pig isolates were classified as (121; 34.1%) or (8; 2.3%), whereas the bovine were identified either as (8; 3.9% isolates) or (3; 1.5% strains). Resistance of the isolates ( = 140) to erythromycin, ciprofloxacin, nalidixic acid, streptomycin, and tetracycline revealed that the vast majority of was resistant to streptomycin (106 isolates; 85.5%), tetracycline (97; 78.2%), nalidixic acid (90; 72.6%), and ciprofloxacin (88; 71.0%). Among isolates ( = 16) the resistance rates to all antibiotics were lower than in , irrespective of the origin. A total of 74 of 121 (61.2%) isolates from the pig carcasses and one of three such isolates from the bovine samples were multiresistant. Most of the (64 isolates; 85.3%) had the ciprofloxacin+nalidixic acid+streptomycin+tetracycline resistance profile. The results suggest that pig and bovine carcasses may be an underestimated reservoir of , especially for in pigs. The high antimicrobial resistance rates of such strains to streptomycin, quinolones, and tetracyclines highlight the need for monitoring of these bacteria in such food and food products.