Poultry products are important in the transmission of zoonotic pathogens, mainly Salmonella. This genus causes millions of foodborne diseases worldwide every year. Cross-contamination by food sources in human cases of salmonellosis and the increase in resistant strains have become important issues. A qualitative and quantitative Salmonella detection method was utilized in a poultry slaughterhouse in São Paulo State, Brazil. We collected 33 samples from different batches of carcasses. Each sample was analyzed at three process points: postbleeding, postdefeathering, and postchilling. A fourth point, retail simulation, was added to simulate retail market storage at 5°C for 72 h. The qualitative methods revealed 100% (33 samples) contamination at postbleeding, 39% (13 samples) contamination at postdefeathering, 58% (19 samples) contamination at postchilling, and 30% (10 samples) contamination at the retail simulation. The quantitative results, determined by the most-probable-number (MPN) technique, ranged from <0.03 to >2,400 MPN/g. We identified 23 Salmonella serovars; the most prevalent were Mbandaka, Senftenberg, and Enteritidis. Resistance to nalidixic acid was significantly more common (P < 0.05) than resistance to other antimicrobial agents. Five multidrug-resistant strains were identified. This study contributes important epidemiological data and demonstrates the need to improve sanitary conditions in slaughterhouses.

Introduction: Salmonella is a major cause of foodborne disease, and poultry products are important contributors to the transmission of this zoonotic pathogen. Although considered to be rare in most countries, Salmonella Corvallis has been reported in specific geographic areas isolated from both human and non-human sources. The aim of this study was to report the occurrence, the antimicrobial resistance profiles including the extended-spectrum beta-lactamase (ESBL) production, and the clonal relatedness of S. Corvallis strains. Methodology: A total of 132 fragments of poultry carcasses from a slaughterhouse in São Paulo State, Brazil, were collected at different stages of the manufacturing process (post-bleeding, post-plucking, and post-chilling) and analyzed for the presence of Salmonella. Antimicrobial resistance was determined by disc diffusion method and Etest. Clonal relatedness was determined by pulsed-field gel electrophoresis (PFGE). Results: Among the 272 Salmonella strains recovered, fourteen were S. Corvallis. Ten (71.4%) showed ESBL production and resistance to at least three antimicrobial agents. Nalidixic acid resistance and reduced ciprofloxacin susceptibility was verified in four (28.6%) strains. PFGE analyses showed that all the S. Corvallis strains belonged to the same pulsotype. Conclusion: This study identified genetically related S. Corvallis strains exhibiting ESBL production and reduced susceptibility to quinolone. The results suggest the need to improve the sanitary conditions in the slaughterhouse. Moreover, from a public health perspective, continuous surveillance on Salmonella is needed to control the dissemination of this important zoonotic pathogen and its resistance determinants.