1.Genome sequence and bioinformatics analysis of an ovine-derived Salmonella enterica strain
Yao WANG ; Longbin KANG ; Renjie WU ; Qiuyong CHEN ; Longbai WANG ; Dingping BAI ; Lunjiang ZHOU ; Yongliang CHE
Chinese Journal of Veterinary Science 2025;45(10):2187-2195
To elucidate the genomic characteristics of Salmonella strains derived from sheep,this study employed various methods,including bacterial isolation and identification,biochemical identi-fication,pathogenicity test,whole-genome sequencing,and BLAST comparison,along with the screening of integrative conjugative elements(ICE)using ICEfinder and EasyFig for comparative analysis,as well as plasmid comparisons utilizing PlasmidBrig.The results revealed the isolation of a Gram-negative,non-spore-forming bacillus from nasal swabs of diseased sheep,which formed gray-white,smooth-surfaced,and neatly edged circular colonies on TSA sheep blood agar.On XLT-4 agar medium,it produced smooth-surfaced,white,circular colonies.The bacterium was identified as Salmonella enterica through 16S rRNA sequencing and biochemical identification.This bacteri-um induces hemorrhaging in the intestines of guinea pigs,resulting in their demise within a 48-hour period.The pathogen exhibits high virulence.Whole-genome alignment demonstrated a high degree of homology with Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7).ICE screen-ing and comparative analysis indicated the presence of a novel ICE in this strain,characterized by a core structural framework that includes an integrative shear module,a mobilizable processing mod-ule,a conjugative pair formation module,and a regulatory module.Notably,ICE from different spe-cies containing the same integrase exhibited identical inverted repeat sequences and insertion sites at tRNAPhe.Plasmid homology comparisons revealed that plasmid sequences from different strains of Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7)also showed high homology;however,the homology with plasmid sequences from other Salmonella and Escherichia coli strains was only 50%.These findings indicate that the isolated strain is Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7)and contains a novel ICE as well as a plasmid.This study fur-ther enriches the molecular epidemiology of Salmonella and provides a theoretical basis for the prevention and control of infections caused by this pathogen.
2.Genome sequence and bioinformatics analysis of an ovine-derived Salmonella enterica strain
Yao WANG ; Longbin KANG ; Renjie WU ; Qiuyong CHEN ; Longbai WANG ; Dingping BAI ; Lunjiang ZHOU ; Yongliang CHE
Chinese Journal of Veterinary Science 2025;45(10):2187-2195
To elucidate the genomic characteristics of Salmonella strains derived from sheep,this study employed various methods,including bacterial isolation and identification,biochemical identi-fication,pathogenicity test,whole-genome sequencing,and BLAST comparison,along with the screening of integrative conjugative elements(ICE)using ICEfinder and EasyFig for comparative analysis,as well as plasmid comparisons utilizing PlasmidBrig.The results revealed the isolation of a Gram-negative,non-spore-forming bacillus from nasal swabs of diseased sheep,which formed gray-white,smooth-surfaced,and neatly edged circular colonies on TSA sheep blood agar.On XLT-4 agar medium,it produced smooth-surfaced,white,circular colonies.The bacterium was identified as Salmonella enterica through 16S rRNA sequencing and biochemical identification.This bacteri-um induces hemorrhaging in the intestines of guinea pigs,resulting in their demise within a 48-hour period.The pathogen exhibits high virulence.Whole-genome alignment demonstrated a high degree of homology with Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7).ICE screen-ing and comparative analysis indicated the presence of a novel ICE in this strain,characterized by a core structural framework that includes an integrative shear module,a mobilizable processing mod-ule,a conjugative pair formation module,and a regulatory module.Notably,ICE from different spe-cies containing the same integrase exhibited identical inverted repeat sequences and insertion sites at tRNAPhe.Plasmid homology comparisons revealed that plasmid sequences from different strains of Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7)also showed high homology;however,the homology with plasmid sequences from other Salmonella and Escherichia coli strains was only 50%.These findings indicate that the isolated strain is Salmonella enterica subsp.diarizonae serotype 61:k:1,5,(7)and contains a novel ICE as well as a plasmid.This study fur-ther enriches the molecular epidemiology of Salmonella and provides a theoretical basis for the prevention and control of infections caused by this pathogen.

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