Association between Clostridioides difficile ribotypes, restriction endonuclease analysis types, and toxin gene expression

Clostridioides difficile strains cause severe infection. Previous studies suggested that the virulence of C. difficile is dependent on ribotype; however, this hypothesis is still controversial. We aim to investigate the relationship between ribotypes, restriction endonuclease analysis (REA) types, and toxin gene expression in C. difficile strains. We utilized 53 clinical C. difficile strains. All strains were assigned a molecular strain type using PCR ribotyping and REA typing and classified into 17 ribotypes and six REA types. The expression of toxin genes (tcdA, tcdB, and cdtB) in C. difficile strains were quantified by real-time PCR using each specific primer set, and expression was normalized to that of the housekeeping gene rpoA. All 53 strains expressed tcdB and four strains expressed cdtB. Five strains did not express tcdA. Most ribotype and REA type strains expressed tcdA and tcdB similar to the BAA-1870 strain. In cdtB-positive strains, the cdtB expression levels were similar to those in the BAA-1870 strain. tcdA and tcdB expression levels were similar in the cdtB-positive and cdtB-negative strains. Toxin gene expression was not associated with the ribotype. Production of binary toxin C. difficile transferase was not related to tcdA and tcdB expression levels. •Virulence of Clostridioides difficile strains is independent of ribotype.•Production of binary toxin CDT is not related to tcdA and tcdB expression.•There is no association between ribotypes/REA types and toxin gene expression.