Enteric pathogens in the pig and wild boar meat chain in Sardinia

This study aimed to (1) characterize pathogenicity, genetic similarity, and antimicrobial resistance (AMR) of Salmonella, pathogenic Escherichia coli, and Yersinia enterocolitica isolates from pigs and wild boars in Sardinia and (2) evaluate the effectiveness of the Sardinian fermented sausage (SFS) production process in controlling Salmonella through a challenge test. Pigs and wild boars are reservoirs of foodborne pathogens, posing public health risks. Regional epidemiological studies are crucial to understanding pathogen prevalence, AMR dynamics, and potential transmission routes in different production systems. Environmental sampling was conducted in six pig farms and slaughterhouses, where Y. enterocolitica was detected in 33.4% of farms, while Salmonella (13.1%) and pathogenic E. coli (26.3%) were only identified in slaughtered pigs. High-risk globally distributed E. coli strains (ST88, ST101, ST648) were isolated. More than half of commensal E. coli isolates carried AMR genes, particularly for tetracycline and ampicillin. In wild boars, Salmonella was found in 4.5% of animals, while Y. enterocolitica was detected in 30.3%. Novel Salmonella enterica serotype and Escherichia species (E. marmotae, E. ruysiae) and pathogenic E. coli were identified, with a lower prevalence of antimicrobial resistance compared to domestic pigs. The challenge test, conducted on three batches of SFS, involved Salmonella inoculation during mixing. Although fermentation reduced microbial load, the pathogen remained detectable at the end of production and after 40 days. The findings emphasize the need for enhanced biosecurity measures in farms and continuous monitoring of enteric pathogens in both domestic and wild swine. Whole genome sequencing analysis provided deeper epidemiological insights, confirming genetic links among isolates and identifying risk factors along the production chain. Findings provide insights for risk management in meat production and emphasize the importance of strict control over raw materials, fermentation and maturation to ensure food safety.

This study aimed to (1) characterize pathogenicity, genetic similarity, and antimi-crobial resistance (AMR) of Salmonella, pathogenic Escherichia coli, and Yersinia enterocolitica isolates from pigs and wild boars in Sardinia and (2) evaluate the effectiveness of the Sardinian fermented sausage (SFS) production process in controlling Salmonella through a challenge test. Pigs and wild boars are reservoirs of foodborne pathogens, posing public health risks. Regional epidemiological studies are crucial to understanding pathogen prevalence, AMR dynamics, and potential transmission routes in different pro-duction systems. Environmental sampling was conducted in six pig farms and slaughterhouses, where Y. enterocolitica was detected in 33.4% of farms, while Salmonella (13.1%) and pathogenic E. coli (26.3%) were only identified in slaughtered pigs. High-risk globally distributed E. coli strains (ST88, ST101, ST648) were isolated. More than half of commensal E. coli isolates carried AMR genes, particularly for tetracycline and ampicillin. In wild boars, Salmonella was found in 4.5% of animals, while Y. enterocolitica was detected in 30.3%. Novel Salmonella enterica serotype, Escherichia species (E. marmotae, E. ruysiae) and pathogenic E. coli were identified, with a lower prevalence of antimicrobial resistance compared to domestic pigs. The challenge test, conducted on three batches of SFS, involved Salmonella inoculation during mixing. Although fermentation reduced microbial load, the pathogen remained detectable at the end of production and after 40 days. The findings emphasize the need for enhanced biosecurity measures in farms and continuous monitoring of enteric pathogens in both domestic and wild swine. Whole genome sequencing analysis provided deeper epidemiological insights, confirming genetic links among isolates and identifying risk factors along the production chain. Findings provide insights for risk management in meat production and emphasize the importance of strict control over raw materials, fermentation, and maturation to ensure food safety