Characterization and Implications of the Regionally Prevalent ST8333 Strains of Salmonella enterica Serotype 4,[5],12:i: - China, 2017-2023.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Salmonella enterica is a significant foodborne pathogen responsible for millions of infections and thousands of deaths worldwide each year. The increasing prevalence of the ST34 Salmonella enterica serotype 4,5,12:i:-(S. 4,[5],12:i:-) poses a substantial public health threat in China.

WHAT IS ADDED BY THIS REPORT?: At the end of 2023, the TraNet early-warning module, utilizing whole-genome sequencing data, identified a newly regionally prevalent sequence type of S. 4,[5],12:i:-, designated ST8333, primarily found in Sichuan Province. Analysis revealed high rates of antimicrobial resistance genes, particularly to aminoglycosides and β-lactams. Plasmid comparisons suggest that ST8333 isolates acquired multidrug-resistance plasmids of swine origin during their distribution in Sichuan Province.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: The emergence of ST8333, likely associated with pork consumption, underscores the importance of food safety measures. The high prevalence of multidrug resistance poses challenges for treatment and highlights the need for vigilant surveillance and control measures. Strengthening efforts in regions like Sichuan, identified as a reservoir for multidrug-resistant ST8333 strains, is crucial to prevent further transmission and potential nationwide dissemination. Surveillance and control measures are imperative to curb the spread of multidrug-resistant ST8333 isolates, particularly in high-prevalence regions.