Vancomycin Shows No Significant Effect in Preventing Recurrent C. difficile Infections

Recent research led by the University of Wisconsin–Madison has evaluated the effectiveness of low-dose oral vancomycin in reducing the recurrence of Clostridioides difficile (C. diff) infections among adults. Although initial signs suggested potential benefits, the findings from a well-designed clinical trial indicate that the use of vancomycin during antibiotic therapy did not result in a statistically significant decrease in recurrent C. diff infections.

The study, titled "Oral Vancomycin for Prevention of Recurrent Clostridioides difficile Infection," was a Phase II, double-blind, placebo-controlled randomized trial involving 81 participants. These individuals had previously been treated for C. diff within the last 180 days and were starting systemic antibiotics for other health issues. The participants were recruited from four different health systems, including the University of Wisconsin–Madison, Medical College of Wisconsin, Henry Ford Hospital, and Mayo Clinic.

Participants were randomly assigned to receive either 125 mg of oral vancomycin daily or a lactose placebo during their antibiotic course, continuing for five days afterward. Over the course of the study, researchers monitored symptoms weekly through phone calls and confirmed recurrences using stool toxin assays. The study also examined the carriage of vancomycin-resistant Enterococcus (VRE) in stool samples collected at baseline and after eight weeks.

Results showed that recurrent C. diff occurred in 17 of 39 participants receiving vancomycin (43.6%), compared to 24 of 42 in the placebo group (57.1%). Although this represented a 13.5 percentage point reduction, the difference was not statistically significant (95% confidence interval: −35.1% to 8.0%; p = .22). This outcome was partly attributed to the trial being underpowered, with only 81 participants enrolled instead of the target 150, due to recruitment difficulties and pandemic-related delays.

Moreover, the incidence of VRE colonization was higher among vancomycin recipients, with 50.0% testing positive versus 24.0% in the placebo group. The researchers concluded that while there was a trend toward fewer recurrences with vancomycin, the data was insufficient to definitively support its preventive use. They emphasized the need for further studies with larger sample sizes to determine its true effectiveness.

This research highlights the complexity of preventing recurrent C. diff infections and underscores the importance of cautious antibiotic use to avoid promoting resistance and gut microbiota disruption. Overall, the findings suggest that routine prophylactic use of low-dose vancomycin may not be an effective strategy for recurrent C. diff prevention, and additional research is necessary to explore alternative approaches.