A quantitative PCR to detect non-toxigenic Clostridioides difficile

Area of Science:

• Microbiology
• Molecular Diagnostics
• Infectious Diseases

Background:

• Current diagnostics for Clostridioides difficile infection (CDI) do not identify non-toxigenic C. difficile (NTCD) strains.
• NTCD colonization may confer protection against CDI, but its prevalence is unknown due to diagnostic limitations.

Purpose of the Study:

• To develop and validate a molecular assay for the specific detection of NTCD.
• To assess the prevalence of NTCD colonization in hospitalized patients undergoing testing for CDI.

Main Methods:

• A quantitative PCR (qPCR) assay was designed using specific primers and probes targeting unique regions of NTCD.
• The assay's analytical sensitivity and specificity were validated using reference strains.
• 95 clinical stool samples were analyzed to determine NTCD prevalence in patients tested for CDI.

Main Results:

• The developed qPCR assay demonstrated high analytical sensitivity (linear between 3x10^1 and 3x10^6 gDNA, R^2=0.999).
• NTCD was detected in 20% of samples negative for GDH enzyme and 8.7% of samples positive for GDH enzyme.
• The assay identified NTCD colonization in 7% of the overall hospitalized patient cohort.

Conclusions:

• A novel qPCR assay effectively identifies NTCD strains, enabling their detection in clinical samples.
• NTCD colonization is present in a notable percentage of hospitalized patients, suggesting a potential protective role against CDI.
• This assay has significant implications for improving CDI diagnostics, infection control, and antimicrobial stewardship strategies.