C36 | Poultry supply chain in Sardinia: monitoring of Salmonella contamination and antibiotic resistance profiles

G. Siddi¹, F. Piras¹, M. Migoni¹, L. Bortolami², A. Tiengo², I. Grussu¹, M. Casula¹, F. Manca¹, A. Sau¹, M. Cuccu¹, E. De Santis¹, C. Scarano¹. | ¹Dip. di Medicina Veterinaria, Università di Sassari, Sassari; ²IZS Venezie, Legnaro (PD).

Purpose. The objectives of this study were to evaluate the presence and distribution of Salmonella spp. along the poultry meat supply chain in Sardinia and to characterise the isolated strains by identifying their serotypes and antimicrobial resistance profiles. Methods. Sampling was conducted in four sessions in 2024, distributed throughout the year to ensure seasonal representativeness, and involved different stages of the supply chain: 32 environmental samples (litter, water, feed, footwear) were collected during the rearing phase; 48 samples (12 swabs from cages containing animals and 36 neck skin samples taken after slaughter). Finally, 92 samples of chicken meat purchased from large retail outlets were analysed, divided into 40 samples of cut meat with skin, 40 without skin and 12 samples of chicken meat preparations. A total of 172 samples were tested for Salmonella spp. The isolates obtained were identified by MALDI-TOF mass spectrometry, serotyped and subjected to automated antibiotic susceptibility testing, testing the antibiotics indicated by EU Decision 1729/2020. Results. Salmonella was never detected in samples taken during the rearing and slaughtering phases. Positive results were found exclusively in meat samples, with 21 positive samples out of 92 analysed (overall prevalence 22.8%). The highest prevalence was observed in cuts with skin (11/40, 27.5%), followed by chicken meat preparations (3/12, 25%) and cuts without skin (7/40, 17.5%). Of the 21 isolates, 20 (95%) were identified as Salmonella enterica serotype Infantis, while one isolate belonged to the Thompson serotype. The S. Thompson isolate was sensitive to all antibiotics tested, while all S. Infantis isolates (100%) showed resistance to active ingredients belonging to at least four classes (ciprofloxacin, nalidixic acid, sulfamethoxazole and tetracycline), indicating a high level of multi-resistance. In particular, isolates from skin cuts showed the highest average number of resistances (6.6 ± 0.8), probably due to greater exposure to environmental contamination. Resistance to cefoxitin was found in 7 out of 21 isolates (33%), suggesting the possible presence of AmpC β-lactamase-producing strains. None of the isolates showed phenotypic patterns compatible with ESβL or carbapenemase production. Conclusions. The retail stage remains particularly critical, as it is the last stage before consumption, where cross-contamination and improper food handling can further increase the risk of foodborne infections.