Laboratory Medicine ›› 2017, Vol. 32 ›› Issue (2): 71-75.DOI: 10.3969/j.issn.1673-8640.2017.02.001

• Orginal Article •     Next Articles

Invasion abilities and the virulence gene expressions of Salmonella typhimurium with different origins

DAI Sui   

  1. Department of Clinical Laboratory,Tianjin Fifth Central Hospital,Tianjin 300450,China
  • Received:2016-04-28 Online:2017-03-30 Published:2017-03-30

Abstract:

Objective To analyze the difference of invasion abilities and the virulence gene expressions of Salmonella typhimurium with different origins.Methods A total of 34 isolates of Salmonella typhimurium were collected from soil(strains from soil),water(strains from water) and patients with diarrhea(clinical strains),and their abilities of attachment and invasion to epithelial cells and abilities of replication in macrophages were compared. Real-time fluorescence quantitation polymerase chain reaction(PCR) was used to determine the virulence gene expressions of Salmonella typhimurium with different origins. The virulence genes,including flagella locus filC,Salmonella pathogenicity island-1 loci hilA and invI,and Salmonella pathogenicity island-2 loci ssrA and sseF,were determined.Results The attachment and invasion abilities of strains from soil and water were comparable to those of standard strain(ATCC 14028),while about 80% clinical strains exhibited higher attachment and invasion abilities to epithelial cells. Macrophage replication assay showed that all the strains showed comparable replication ability with that of standard strain(ATCC 14028). The expression patterns of virulence genes in different strains were highly consistent with the results of the attachment and invasion abilities and the replication abilities in macrophages. In line with the results of invasion ability,clinical strains showed high filC,hilA and invI gene expressions relative to that of standard strain(ATCC 14028)(P<0.05),while the gene expressions of ssrA and sseF were not altered. Strains from soil and water showed comparable expression of all the determined genes to that of standard strain(ATCC 14028). Conclusions Clinical strains exhibit higher invasion ability and virulence gene expression than those of environmental strains,and the controlling for clinical strains should be highlighted to prevent from nosocomial infection.

Key words: Salmonella typhimurium, Invasion ability, Virulence gene expression

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