Molecular characteristics and whole genome typing of Salmonella in Changchun from 2018 to 2021
To explore the molecular characteristics of Salmonella strains,reveal the phylogenetic relationships among strains and provide a basis for tracing Salmonella outbreaks,this study collected 105 strains of Salmonella by the active surveillance in Changchun from 2018 to 2021.Whole genome sequencing and bio-informatics analysis were used to detect virulence genes,followed by whole genome single nucleotide polymorphism(wgSNP),multilocus sequence typing(MLST)and complete genome multilocus sequence typing(cgMLST).A total of 144 virulence genes in Salmonella strains were analyzed,and the results showed that the genes in Salmonella pathogenicity islands(SPIs)were relatively stable.However,the virulence factors of non-secretory system were varied significantly among different serotypes of Salmonella.The cgST and ST types of the 105 Salmonella strains were identical,totaling 13 types.The major epidemic strains,Salmonella enteritidis(ST11)and Salmonella I 4,[5],12:i:-(ST34),were closely related to foreign epidemic strains.This study confirmed that the virulence genes carried by Salmonella in Changchun are relatively stable.The major epidemic strains distributed across specimens from different years and sources,and their molecular characteristics are consistent with those of foreign epidemic strains.The serotype of Salmonella is closely related to its ST type and cgST type.
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