Strain Variation in Clostridioides difficile Cytotoxicity Associated with Genomic Variation at Both Pathogenic and...

Area of Science:

• Microbiology
• Genetics
• Infectious Diseases

Background:

• Clostridioides difficile infection (CDI) is a major healthcare concern, primarily linked to toxins A and B encoded within the PaLoc.
• The role of genomic variation outside the PaLoc in modulating CDI virulence remains underexplored.

Purpose of the Study:

• To investigate the influence of genomic variants outside the PaLoc on C. difficile cytotoxicity.
• To identify non-PaLoc genetic loci associated with C. difficile virulence phenotypes and clinical severity.

Main Methods:

• Phylogenetic analysis to assess discordance between cytotoxicity and PaLoc evolution.
• Elastic net modeling to evaluate the predictive power of PaLoc variants for cytotoxicity.
• Bacterial genome-wide association study (GWAS) using a convergence-based approach to identify non-PaLoc loci linked to cytotoxicity and other phenotypes.

Main Results:

• Cytotoxicity of C. difficile is significantly influenced by genomic variants located outside the PaLoc.
• Multiple non-PaLoc loci were identified as correlating with changes in cytotoxicity.
• Other in vitro phenotypes like germination and sporulation also show variable associations with genomic variation and clinical severity.

Conclusions:

• A model of C. difficile disease incorporating numerous non-PaLoc loci is supported.
• Non-PaLoc genetic variations offer potential targets for novel CDI therapeutic interventions.
• Overlapping loci identified through GWAS may be crucial for both bacterial function and clinical disease outcomes.