The Cytopathic Effect of Different Toxin Concentrations From Different Clostridioides difficile Sequence Types Strains in Vero Cells

Abstract

Clostridioides difficile is one of the leading causes of healthcare-associated diarrhea, with severity ranging from mild, self-limiting disease, to life-threatening toxic megacolon. C. difficile infection (CDI) pathogenesis is mediated by the TcdA and TcdB toxins. This work aimed to draw correlations between toxin levels, bacterial strains, and disease severity in 63 CDI patients. C. difficile typing was performed by multi-locus sequence types (MLST). Toxin concentrations were measured using the TOX A/B test. In addition, cell cytotoxicity assay was performed following Vero cell exposure to stool extracts (24 h). The most prevalent sequence types (ST) were ST2, ST4, ST6, ST13, ST37, ST42, and ST104, with highest toxin levels produced by ST42 and ST104 (302.5 and 297.1 ng/ml, respectively). These strains had a stronger cytopathic effect (CPE) on Vero cells as compared to strains with lower toxin concentrations (p < 0.001), as manifested by lower cell counts and higher percentages of cell rounding and adhesion loss. Although no association was found between ST, toxin concentrations, and disease severity, a diverse in vitro effect of different STs on the viability and activity of Vero cells was observed. These findings suggest that disease severity is affected by both host immune responses and by bacterial characteristics.

Butyrate enhances Clostridioides difficile sporulationin vitro

“…We next assessed the impact of SCFAs on C. difficile toxin and spore production, which typically occur during stationary stage (60). We assessed toxin production in the presence of SCFAs using an in vitro cell rounding assay (61). After 24 hours of growth, we observed increased toxin by C. difficile strain 630 in the presence of all SCFAs, compared to BHI alone (Figure 3A, Dunnett's Test, p < 0.001).…”

Butyrate enhances Clostridioides difficile sporulation in vitro

“…We next assessed the impact of SCFAs on C. difficile toxin and spore production, which typically occur during the stationary growth phase ( 61 ). We assessed toxin production in the presence of SCFAs using an in vitro cell rounding assay ( 62 ). After 24 h of growth, we observed increased toxin by C. difficile strain 630 in the presence of all SCFAs, compared to BHI alone ( Fig.…”

Update on Commonly Used Molecular Typing Methods for Clostridioides difficile

“…There has been previous research on the relationship between the levels of toxins produced by different strains of C. difficile and disease severity, but it has yielded contradictory results. However, a recent study that investigated the impact of different STs [ 142 ] found that, although there was no significant association between toxin levels and disease severity, ST 42 and ST 104, which produce high levels of toxins, had the most significant effects on cell proliferation, causing a reduction when compared to control cells. Additionally, ST 37 had a more severe impact on cell morphology.…”