Study of the relationships among known virulence genes, coccoid transformation and cytotoxicity of in different clinical diseases.

BACKGROUND

has infected approximately 4.4 billion individuals worldwide. The known virulence genes and the existing typing methods have not been shown to have a recognized correlation with its infectivity. The aim of this study was to elucidate the relationships among known important virulence genes, coccoid transformation, and cytotoxicity of isolated from individuals with different clinical diseases to provide guidance for the development of new virulence typing methods for .

METHODS

The known important virulence genes of 35  strains were identified by whole-gene next-generation sequencing (WGS) and polymerase chain reaction (PCR). The chronological changes in the proportion of coccoid forms of and their ultramicroscopic structures were observed chronologically using transmission electron microscopy. Human gastric mucosal epithelial cells (GES-1) were infected with strains in vitro to evaluate cytotoxicity of .

RESULTS

There were no significant correlations among the known important virulence genes, coccoid transformation and cytotoxicity of isolated from patients with different clinical diseases. We developed a new virulence classification based on the defensive and offensive abilities of .

CONCLUSIONS

Coccoid transformation and virulence are two independent characteristics of that reflect its defensive and offensive abilities, respectively. These two abilities work synergistically, warranting the construction of a new virulence typing method for . However, the correlation between the new virulence classification and pathogenic ability still needs to be further verified.