Multi-strain Clostridioides difficile infection: Increased detection and clinical implications

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Clostridioides difficile infection (CDI) is a significant cause of antibiotic-associated diarrhea.
• While mixed-strain (MS) CDI has been observed, its clinical implications remain unclear.
• Understanding strain dynamics in CDI is crucial for effective treatment and prevention strategies.

Purpose of the Study:

• To investigate the prevalence of multi-strain (MS) Clostridioides difficile isolates in patients diagnosed with CDI.
• To evaluate the clinical implications of MS infection, including disease severity and recurrence.
• To identify specific C. difficile strains and their toxin profiles in single-strain (SS) and MS infections.

Main Methods:

• Fecal specimens from 174 CDI patients were cultured, and three C. difficile colonies per sample were analyzed for toxin gene profiles via PCR.
• A subset of specimens (n=62) underwent whole-genome shotgun sequencing for detailed strain analysis.
• Clinical data from 160 patients were analyzed to correlate infection type with outcomes.

Main Results:

• Multi-strain (MS) CDI was identified in 32.8% of patients.
• The most common toxin profiles involved combinations of toxin A, toxin B, and binary toxins.
• In MS cases, the presence of non-toxigenic strains was associated with a significantly decreased risk of severe CDI (p=0.0098).
• Whole-genome sequencing confirmed MS infections and identified ST2 and ST42 as common sequence types in MS and SS cases, respectively.

Conclusions:

• A high prevalence of MS infection exists in Clostridioides difficile-infected patients.
• Non-toxigenic C. difficile strains in MS infections appear to mitigate disease severity.
• Strain-specific interactions in MS infections warrant further investigation regarding treatment outcomes.