Salmonella Serovars Distribution in Poultry Meat and Genetic Characterization of Antimicrobial-Resistant Isolates: A Five-Year Monitoring in Sicily

Salmonellosis is one of the most frequently reported zoonoses, and broiler meat/meat products are among its main vehicles of transmission. Continuous monitoring on Salmonella serovars and the spread of antimicrobial resistance is essential for epidemiological surveillance. From 2021 to 2025, a total of 350 poultry samples were collected in Sicily and analyzed for Salmonella spp. detection, serotyping and antimicrobial resistance (AMR) phenotyping. Overall, 101/350 samples tested positive for Salmonella spp. Eight serovars were identified with S. Infantis being the most prevalent, followed by S. Kentucky, S. Enteritidis, S. Strathcona, S. Agona, S. Corvallis, S. Toulon, S. Virchow. The following resistance percentages were revealed: 78.7% (144/183)—tetracycline, 68.9% (126/183)—trimethoprim-sulfamethoxazole, 51.9% (95/183)—penicillins, 35.0% (64/183)—third-generation cephalosporins, 33.3% (61/183)—aminoglycosides, 4.9% (9/183)—chloramphenicol, 2.2% (4/183)—fluoroquinolones, 0% (0/183)—imipenem. The following genetic determinants were searched in a selected subset of 46 isolates resistant/intermediate resistant (R/I) to third-generation cephalosporins or fluoroquinolones: blaCTX-M-1, blaCTX-M-2, blaCTX-M-4, blaCMY-2, blaTEM, blaOXA, blaSHV (third-generation cephalosporins); qnrA, qnrB, qnrC, qnrD, qnrS, qepA, oqxAB, aac(6′)-Ib (fluoroquinolones) and intI1. High proportions of R/I isolates (78.6% for third-generation cephalosporins, 100% for fluoroquinolones) carried at least one of the resistance determinants. All of them carried intI1. Our data confirm that poultry meat and poultry-based foods represent important vehicles of Salmonella and that S. Infantis is the predominant serovar. The high rate of AMR is of concern for human safety and environmental health, especially referring to the highest priority and critically important antimicrobials (hpCIAs) such as third-generation cephalosporins.