A recent study published online as an unedited 'Article in Press' in the journal npj Science of Food found that the riskiest points for drug-resistant Salmonella may emerge after pigs leave the farm, according to a global genomic analysis and field sampling conducted in China on Jul. 30.
Researchers investigated the association between pork supply chains and the evolution of antimicrobial resistance in Salmonella enterica by integrating global genomic datasets from both human and swine sources with field samples collected along a pork supply chain in Guangdong, China. The study assessed whether specific stages of the supply chain were linked to Salmonella contamination and enrichment of resistance genes.
The findings identified S. enterica serovar 4,[5],12:i:- ST34 as a prominent lineage associated with humans and swine that carries a high burden of resistance genes. The study indicated that downstream slaughterhouse and retail stages, particularly within developing-country pork systems like those studied in Guangdong, are potential hotspots for higher recovery rates of Salmonella and increased presence of resistant lineages.
Field data showed that Salmonella isolation rates increased from farms (4.52%) to slaughterhouses (48.22%), reaching their highest levels at retail markets (63.16%). Multidrug resistance was most prevalent among slaughterhouse isolates (84.73%), while extensive drug resistance was highest among retail market isolates (30.55%). Genomic analyses further confirmed S. 4,[5],12:i:- ST34 as the dominant serovar and lineage within these settings.
The authors said that "farm-level biosecurity alone may be insufficient to mitigate foodborne risks," and concluded that effective mitigation requires integrated One Health strategies focusing on slaughterhouse sanitation, improvements to cold-chain infrastructure, enhanced surveillance at retail markets, and risk-based genomic monitoring across pork supply chains.
