A Closer Look at the Risk: A Review of Prior Antimicrobial Use of Patients with Clostridium difficile Infection

Background: Antibiotic therapy is the most important risk factor for development of Clostridium difficile infection (CDI). Several studies have demonstrated that up to one-third of antibiotic therapy prescribed in hospitals may be unnecessary.

Objective: To test the hypothesis that a significant proportion of CDI patients have received unnecessary antibiotic therapy in the 90 days prior to the CDI diagnosis.

Methods: A 6-month prospective observational study of all hospitalized patients with CDI was conducted in a Veterans Affairs hospital. Medical records were reviewed to assess whether antibiotic therapy received in the 90 days prior to the diagnosis of CDI was necessary based on standard guidelines or principles for treatment of infectious diseases.

Results: Of 48 patients with CDI, 42 (88%) had received one or more antibiotic courses in the 90 days prior to their diagnosis and 40 (83%) had received antimicrobials in the past 30 days. Fourteen of 42 (33%) CDI patients with prior antibiotic therapy received one or more unnecessary courses of antibiotic therapy. Of 577 total days of antibiotic therapy received in the 90 days prior to diagnosis of CDI, 162 (28%) were deemed unnecessary. The most common reasons for unnecessary therapy included administration of antimicrobials for noninfectious or nonbacterial syndromes, treatment of colonization nor contamination, and longer than necessary duration of therapy.

Conclusions: In our institution, hospitalized patients with CDI have often received unnecessary antibiotic therapy prior to their diagnosis. These findings suggest that effective antimicrobial stewardship programs could potentially prevent a significant proportion of CDI cases.