Abstract: Objective To understand the serotypes, molecular typing characteristics, and drug resistance of Salmonella in food surveillance and case surveillance in Cangzhou City from 2021 to 2023, and to provide the reference for reducing and controlling the prevalence of drug-resistant strains of Salmonella. Methods Food samples and foodborne disease active surveillance samples were collected from 2021 to 2023 in Cangzhou City, Salmonella strains were isolated, drug sensitivity tests were carried out using an automatic drug sensitizer, diagnostic sera were serotyped, and molecular typing was performed by whole genome sequencing. Results A total of 84 strains of Salmonella were detected in 1 258 samples, the detection rate was 6.7%. There were 26 serotypes, among which Salmonella typhimurium (2.1%), Salmonella enteritidis (1.5%), and Salmonella Kentucky (0.5%) had higher detection rates. Salmonella typhimurium, Salmonella enteritidis, Salmonella Kentucky, and other Salmonella were resistant to 13, 12, 13, and 13 kinds of antibiotics, respectively. The resistance to ampicillin was the highest in 84 strains (76.2%), followed by tetracycline (61.9%) and streptomycin (47.6%), and polymyxine E and tigacycline were the most sensitive (0.0%). Based on the cluster analysis of wgSNP (whole gene single nucleotide polymorphism), there were two dominant typing groups, namely ST34 and ST11, there were homologous strains, but the drug resistance spectrum was not exactly the same. Conclusions Food-borne and human-borne Salmonella in Cangzhou exhibit drug resistance and multidrug resistance. The molecular typing is polymorphic and demonstrates significant superiority. It is imperative for relevant departments to enhance monitoring efforts to anticipate the emergence and prevalence of drug-resistant strains of Salmonella.

Key words: Salmonella, Serotypes, Molecular typing, Drug resistance