Epidemiological status and etiological characteristics of Salmonella detected in meat and meat products in Gansu, 2021−2023

Objective To understand the etiological characteristics of Salmonella detected in meat and meat products in Gansu province from 2021 to 2023, and provide basic research data for risk identification of Salmonella in meat and meat products in Gansu.

Methods Whole genome sequencing of strains of Salmonella isolated from meat and meat products collected from farm produce markets, wholesale markets, supermarkets, and retail processing stores in Gansu from 2021 to 2023 was performed by using illumina second-generation sequencing platform. The sequencing data were used for serotype analysis, multilocus sequence typing, clustering analysis and virulence gene screening with software BioNumerics 7.6.

Results The 44 strains of Salmonella isolated from 683 meat and meat products collected, 44 strains of Salmonella could be divided into 16 serotypes, of which Salmonella Enteritidis was predominant. A total of 17 sequence types (ST) were identified, and ST11 was predominant. The 44 strains of Salmonella were divided into 3 different clades, and the strains in different clades were detected in different years and different areas. A total of 157 virulence genes were detected, of which 98 virulence genes were detected in all the 44 strains of Salmonella, and the remaining 59 virulence genes were detected in 44 strains of Salmonella in different proportions.

Conclusion Salmonella Enteritidis, belonging to ST11 and carrying Salmonella pathogenicity islands virulence genes and structural virulence factors, was mainly detected in meat and meat products in Gansu from 2021 to 2023, and the serotype was related to the sequence type to a certain extent, and the strains in different years and different areas shared homology to some degree.