Effect of hcp1 of the Type VI Secretion System on Biological Characteristics of F18 Shiga Toxin-Producing Escherichia coli

The objective of this study was to investigate the effect of hcp1, a main structural gene of type VI secretion system (T6SS), on the biological characteristics related to the virulence factor of F18 Shiga toxin-producing Escherichia coli (STEC). In this study, based on the construct of the wild type F18 STEC (F18), hcp1 deletion mutant (F18ab Delta hcp1) and complement strain (F18ab Delta hcp1/phcp1), their pathogenic differences were compared, and the function of hcp1 was discussed from the aspects of growth curve, biofilm formation, adherence, invasion, cytotoxicity, and so on. The results showed that hcp1 of the T6SS did not influence bacterial growth and biofilm formation. In F18ab Delta hcp1, bacterial motility, adherence and invasion towards the intestinal porcine enterocyte cells (IPEC-J2) were reduced significantly, and the cytotoxicity decreased. The results of RT-PCR showed that in F18ab Delta hcp1, the flagella gene flic and type I fimbriae fimA were significantly down-regulated. In conclusion, hcp1 gene of F18 STEC is related to flagella expression, bacterial adherence, invasion, and secretion of Stx2e toxin. T6SS hcp1 is proved to be closely involved in the pathogenesis of F18 STEC.

Automated summary

The objective of this study was to investigate the effect of the hcp1 gene on the virulence factors of F18 Shiga toxin-producing Escherichia coli. The results showed that the hcp1 gene is involved in bacterial motility, adherence, invasion, and secretion of Stx2e toxin.