Efficacy of Secondary Prophylaxis With Vancomycin for Preventing Recurrent Clostridium difficile Infections

OBJECTIVES: Patients with Clostridium difficile infection (CDI) who are re-exposed to antibiotics have a high likelihood of recurrence. We aimed to determine whether oral vancomycin as secondary prophylaxis reduces the risk of recurrence in patients recently diagnosed with CDI who undergo subsequent antibiotic exposure (CDI-AE). METHODS: We conducted a retrospective cohort study of patients diagnosed with CDI (initial episode or recurrence) between 2003 and 2011 in two tertiary care centers in Quebec, Canada and who received antibiotics not targeted against CDI within 90 days after their CDI diagnosis. Risk factors for subsequent recurrence after this exposure to antibiotics were assessed through Cox regression analyses. RESULTS: We included 551 episodes of CDI-AE (379 initial episodes, 172 recurrences). Recurrence occurred after exposure to antibiotics in 181 episodes (32.9%). Recurrence was more likely in older patients (for each additional year of age: adjusted hazard ratio (AHR), 1.01; 95% confidence interval (CI), 1.00-1.03; P=0.02) and among cases where the CDI-AE episode was itself a first (AHR, 3.59; 95% CI, 2.52-5.13; P<0.0001) or a second recurrence (AHR, 4.88; 95% CI, 3.38-7.06; P<0.0001). Oral vancomycin prophylaxis decreased the risk of further recurrence in patients whose CDI-AE itself was a recurrence (AHR, 0.47; 95% CI, 0.32-0.69; P<0.0001) but not in those whose CDI-AE was an initial episode (AHR, 0.91; 95% CI, 0.57-1.45; P=0.68). CONCLUSIONS: Oral vancomycin appears as an effective strategy for decreasing the risk of further CDI recurrence in patients with a history of recurrent CDI who are re-exposed to antibiotics.