A recent study has shown that oral vancomycin prophylaxis (OVP) significantly reduces the incidence of Clostridioides difficile infection (CDI) during hospitalization in autologous stem cell transplant (ASCT) recipients, without increasing the risk of infection after discharge. The study, conducted at a single institution, evaluated 254 ASCT patients between January 2012 and December 2021. Patients were divided into two groups: those who received OVP (125 mg twice daily) and those who did not. The primary outcome, the incidence of CDI during hospitalization, revealed a significantly lower CDI rate in the OVP group (4%) compared to the non-OVP group (11%), with a p-value of .03.
The secondary outcome, assessing CDI risk up to 180 days after discharge, found no increased risk following OVP discontinuation. The study also identified longer hospital stays as a factor associated with a higher risk of CDI.
In an interview with Contagion, Michael Williams, PharmD, the study’s lead investigator, addressed concerns about the long-term effects of OVP, particularly regarding antibiotic resistance and microbiome disruption. He explained, “Based on the significant reduction of in-hospital CDI incidence, we expect the benefit to occur acutely during the immediate early transplant period, especially prior to cell engraftment. A potential long-term risk remains promotion of vancomycin resistance, however multiple studies have dispelled this concern (Morisette 2019 and Altemeier 2022). Concern for gut microbiome disruption is valid but has yet to be fully elucidated. In our study, the timing of CDI did not exactly correlate with time periods identified as highest risk due to antimicrobial-related microbiota disruption. Given there was no increased risk for CDI post-OVP discontinuation, compared to those who were OVP-naive, we do not have reason to suspect increased OVP-induced risk of CDI development long term. Data surrounding risk of Gram-negative infections are mixed.”