To investigate the contamination and antimicrobial resistance status of Salmonella and diarrheagenic Escherichia coli in commercially available foods in Jiangsu Province.

A total of 8110 samples of commercially available foods were collected in Jiangsu Province from 2022 to 2024. Salmonella and diarrheagenic Escherichia coli were detected and typed using the methods specified in the National work manual for food contaminant and hazardous factor risk monitoring, and antimicrobial susceptibility testing was performed by the broth microdilution method.

The overall detection rate of Salmonella and diarrheagenic Escherichia coli was 4.6% and 2.9%, respectively. Meat and meat products had the highest detection rates of both pathogens, which were 9.9% for Salmonella and 4.7% for diarrheagenic Escherichia coli, followed by aquatic products, with the rate of 2.4% and 1.9%. The 49 kinds of serotypes were identified among the 262 Salmonella strains, 37 strains could not be typed. Salmonella enteritidis, Salmonella typhimurium and Salmonella kentucky were the dominant serotypes. Among the 116 diarrheagenic Escherichia coli isolates, most were enteroaggregative Escherichia coli (EAEC), accounting for 87.1%. Both Salmonella and diarrheagenic Escherichia coli showed high resistance rates to tetracycline, ampicillin and chloramphenicol, while they were relatively sensitive to tigecycline and carbapenem antibiotics. The multi-drug resistance rates of Salmonella and diarrheagenic Escherichia coli were 65.3% and 59.5%, respectively.

Salmonella isolated from commercially available foods in Jiangsu Province have diverse serotypes.Both Salmonella and diarrheagenic Escherichia coli exhibit high levels of antimicrobial, multidrug resistance and complex resistance spectra. This issue demands great attention from animal husbandry and regulatory authorities.