BACKGROUND AND GOALS: Fidaxomicin is a new antibiotic used to treat Clostridium 
difficile infection (CDI). Given limited clinical experience with fidaxomicin, 
we assessed outcomes in a diverse cohort of patients with CDI treated with 
fidaxomicin.
STUDY: All CDI cases treated with fidaxomicin at 3 referral centers over a 
4-year period were included. Response was defined as resolution of diarrhea and 
recurrence was defined by recurrence of CDI within 8 weeks of the end of 
treatment.
RESULTS: Overall, 81 patients (median age 55.9 y; 53% female; 26% with 
inflammatory bowel disease) were included. Response occurred in 90%. Responders 
had fewer prior CDI episodes [median 1 (range, 0 to 8)] than nonresponders 
[median 2.5 (range, 1 to 8)], P=0.01. Response after a first CDI episode was 
100%, 96% after 1 prior episode, and 82% after 2 or more, P=0.02. Recurrence 
occurred in 19%. Patients without recurrence had fewer prior episodes of CDI 
[median 1 (range, 0 to 6)] than patients who recurred [median 2 (range, 1 to 
8)], P=0.005. Recurrence after a first episode was 0%, 23% after 1 prior 
episode, and 29% after 2 or more, P=0.005. All patients with inflammatory bowel 
disease responded either with improvement of symptoms or a negative C. difficile 
test; 19% recurred.
CONCLUSIONS: All patients with a first CDI episode treated with fidaxomicin 
responded with no recurrences. Patients with prior CDI episodes were less likely 
to respond (especially with more than 1 prior episode) and more likely to recur, 
suggesting a greater clinical benefit of fidaxomicin earlier in the course of 
CDI.