Author Interviews, C. difficile, Hospital Acquired, JAMA / 05.05.2015
Non-Toxic Spores May Prevent C. difficile infection
MedicalResearch.com Interview with:
Dale N. Gerding, MD
Research Physician, Edward Hines, Jr., VA Hospital
Professor, Department of Medicine of Loyola University Chicago Stritch School of Medicine
Medical Research: What is the background for this study? What are the main findings?
Dr. Gerding: Naturally occurring strains of C. difficile lack the genes for production of the toxins that cause C. difficile infection (CDI) and are known as non-toxigenic C. difficile (NTCD). These strains when ingested by patients whose normal microbiota is disrupted by antibiotic treatment will harmlessly colonize the colon and remain in the gut for weeks to months. Specific strains of NTCD found in patients were shown to colonize the gut and prevent C. difficile infection when challenged with toxigenic C. difficile strains in animal models. One such NTCD strain, NTCD-M3, was shown to be safe and well tolerated in human volunteer trials and was used in the present study to determine if it would prevent recurrence of C. difficile infection in patients who had just completed treatment with vancomycin or metronidazole of either their first CDI episode or first recurrence of
C. difficile infection. 168 patients were randomized to receive by mouth in a liquid form, either 10,000 spores/day of NTCD-M3 for 7 days, 10 million spores/day for 7 days, 10 million spores/day for 14 days, or an identical placebo for 14 days. Primary outcome was safety, and secondary outcomes were the percent who colonized the gut with NTCD-M3 in the time period from end of treatment to week 6, and the rate of recurrent CDI in the patients at week 6. The results showed that NTCD-M3 was safe and well tolerated, and colonized the gut of 69% of patients who received it. The C. difficile infection recurrence rate was 30% in the placebo patients and 11% in patients who received any of the NTCD-M3 doses (P<.006). The best dose tested was 10 million spores/day for 7 days which resulted in a recurrence rate of only 5% (p<.01 vs placebo). Colonization of the gut was not permanent, but lasted a maximum of 22 weeks. The summary conclusion is that NTCD-M3 is safe, colonized the gut, and when it colonized the gut, reduced recurrence of C. difficile infection to 2% (p<.001 vs patients who were not colonized).
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