Clostridioides difficile infection (CDI) is the major cause of diarrhea associated with the use of antibiotics, and the most common one in hospitalized patients [1,2]. In the last decade the incidence of CDI has dramatically increased worldwide, especially in its recurrent form [3]. Increasing rates of recurrences are a major challenge for the management of CDI, accounting for nearly 35% of patients after their first episode of infection [4].These patients undergo repeated antibiotic cycles, that sustain the disruption of gut microbiota, increasing the risk of further recurrences (up to 65% after two or more recurrences) and of more severe clinical pictures [[5], [6], [7], [8]]. Specific populations of patients appear to be more susceptible to acquire CDI and experience disease recurrence. Specifically, patients with inflammatory bowel disease (IBD), a group of chronic intestinal disorders that includes Crohn's disease (CD) and ulcerative colitis (UC), experience a 2.5 to 8-fold higher prevalence of CDI than standard population [9,10], as well as higher likelihood of recurrence after a first CDI episode [9,11,12]. CDI superinfection is also associated with an increase in hospitalization rates and length of hospital stay, severity of underlying IBD, escalation of IBD therapy, and complications as colectomy and death [13].Notably, IBD is associated with alteration of healthy gut microbiome (mainly loss of alpha diversity and decrease in the abundance of commensal bacteria) and impairment in host immunity [[14], [15], [16]], which are key factors in the pathogenesis of CDI [17].This evidence supports the identification of gut microbiome as a therapeutic target in these overlapping disorders.

Fecal microbiota transplantation (FMT), that is the transfer of healthy donor feces into the gut of a recipient with a disease associated with microbiome imbalance, is the most powerful modulator of gut microbiota. As recommended by several international guidelines [[18], [19], [20]], FMT is an established treatment for patients with multiply recurrent CDI (rCDI), being not only more effective than antibiotics [21],but also able to prevent CDI-related complications [22,23].

A growing body of evidence shows that FMT is an effective treatment in patients with IBD and rCDI superinfection, being able not only to cure the infection but also to improve disease activity and decrease the need for escalation of IBD therapy [[24], [25], [26], [27]].

Recently, we reported outcomes from a case series of 18 patients with IBD treated with FMT for rCDI. Our results were in line with previous reports, but we also found that this population required multiple fecal infusion (sequential FMT) more often than patients without IBD to cure CDI [28].To strengthen our findings, and as patients with UC achieved different cure rates after FMT than those with CD, we aimed expanding our cohort and focusing only on patients with UC and rCDI, reporting outcomes of FMT in this specific population.