Clostridium difficile infection (CDI) is an important cause of diarrhea and continues to be a major burden within healthcare institutions and in the community. For a small subset of patients with frequently relapsing CDI who do not have access to fecal microbiota transplantation (FMT), or fail FMT, there are no clear treatment recommendations. We review our experience with prolonged oral vancomycin for secondary prophylaxis of relapsing CDI. We performed a retrospective chart review of cases from the C. difficile consultation service at our institution since 2013. The service had three primary physicians providing consultations and performing over 1000 FMTs over the five-year period. Patients with relapsing CDI who were not candidates for FMT, refused, or relapsed after FMT were treated with vancomycin, followed by long-term oral vancomycin at a dose of 125 mg once daily. Twenty patients received at least 8 weeks of once-daily oral vancomycin for prophylaxis of relapsing CDI. Patients had a median age of 80 years, and experienced a median of four episodes of CDI prior to long-term vancomycin. Most were female and 75% had received FMT. Only a single case of C. difficile relapse occurred while on long-term vancomycin during 200 patient-months of follow-up. Amongst those who stopped long-term vancomycin, 31% relapsed within 6 weeks. No adverse events were observed. For elderly patients with frequently relapsing C. difficile, prolonged vancomycin once daily at a dose of 125 mg orally was effective in preventing further relapse. Vancomycin secondary prophylaxis may be considered in patients who have failed FMT, or in cases where FMT is not available.

Background: Clostridium difficile infection (CDI) is one of the most common healthcare-associated infections (HAI) in the United States and Canada, and incidence rates have increased worldwide in recent decades. Currently, antibiotics are the mainstay treatments for both primary and recurrent CDI, but their efficacy is limited, prompting further therapies to be developed. Aim: This review summarizes current and emerging therapies in CDI management including antibiotics, fecal microbiota transplantation, monoclonal antibodies, spore-based therapies, and vaccinations.

Computational topologists recently developed a method, called persistent homology to analyze data presented in terms of similarity or dissimilarity. Indeed, persistent homology studies the evolution of topological features in terms of a single index, and is able to capture higher order features beyond the usual clustering techniques. There are three descriptive statistics of persistent homology, namely barcode, persistence diagram and more recently, persistence landscape. Persistence landscape is useful for statistical inference as it belongs to a space of $p-$integrable functions, a separable Banach space. We apply tools in both computational topology and statistics to DNA sequences taken from Clostridioides difficile infected patients treated with an experimental fecal microbiota transplantation. Our statistical and topological data analysis are able to detect interesting patterns among patients and donors. It also provides visualization of DNA sequences in the form of clusters and loops.