Clostridioides difficile can colonize the mucus layer of the colon, which may allow it to evade treatment and be a factor in recurrent C difficile infection (CDI), according to research presented at the 2020 American College of Gastroenterology (ACG) Annual Scientific Meeting.

In this pilot study, patients underwent flexible sigmoidoscopy to obtain sigmoid colon biopsies within 2 weeks of completing antibiotic therapy for recent CDI infection. Samples were fixed in methacarn solution and stained with 4′, 6-diamidino-2-phenylindole (DAPI) for DNA and fluorescence in situ hybridization (FISH) probes for bacteria (EUB388), mucin (MUC2), and a C difficile 16S rRNA-specific probe. Clinical information was obtained after reviewing electronic health records, and the participants were contacted 8 weeks after CDI treatment to determine if recurrent infection had developed.

A total of 17 patients completed the study (mean age 53.4 years; 64.7% women). The investigators found that 5 patients (29.4%) experienced recurrent CDI (4 confirmed by C difficile stool testing and 1 based on symptom recurrence and favorable response to treatment) within 8 weeks of treatment. No significant differences were observed regarding age, gender, recent hospitalization, or recent antibiotic use between participants with and without recurrence.


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The researchers also assessed for the presence of C difficile in the colonic biopsy specimens using FISH and detected C difficile on tissue staining in 2 of 5 (40.0%) patients who subsequently developed recurrent infection compared with 3 of 12 (25.0%) patients without recurrence. Colonic mucosal permeability was found to be higher in patients who developed recurrent CDI compared with those who did not (P =.056).

The investigators findings indicate that C difficile can colonize the colonic mucus layer, which may allow it to evade treatment and contribute to recurrent CDI.  They suggest that mucosal colonization of C difficile following treatment and increased colonic mucosal permeability may predict recurrence of infection.

Reference

Schupack DA, Pu M, Si J, et al. Mucosal association of Clostridioides difficile in the colon may play a role in infection recurrence. Paper presented at: 2020 Annual Scientific Meeting of the American College of Gastroenterology; October 26-28, 2020. Abstract P0467 (S0248).