Clostridium difficile infection following community-acquired pneumonia

Introduction: In this prospective observational study of hospitalized community acquired pneumonia (CAP) patients, we determined the incidence Clostridium difficile infection (CDI) and its contribution towards treatment failure. Methods: Data were recorded for 1883 consecutive CAP patients. All patients with 2 or more loose stools during these admissions, had samples sent for Clostridium difficile toxin testing. The association of specific risk factors and development of CDI was assessed by multivariable logistic regression (MVR). Results: There were 51 cases of CDI following CAP (2.7% of CAP cases). The most frequent antibiotic regimes implicated were amoxicillin/clavulanic acid +/- macrolide (54.9%) or regimes containing cephalosporins (35.3%.). 37.3% of CDI cases received more than 2 antibiotics (excluding those used to treat CDI), while only 3 patients were on monotherapy. Mortality secondary to CDI was 21.6% as inpatient, rising to 43.1% at 1 year (compared to 1 year mortality for all CAP patients of 21.3%, p=0.0001). Overall mortality rate for CAP patients was 9% at 30 days. In MVR analysis, the factors associated with development of CDI were age (AOR 1.04 95% CI 1.01-1.08, p=0.03), duration of admission (AOR 1.06 95% CI 1.04-1.09, p<0.0001), total number of antibiotics during admission (AOR 2.59 95% CI 1.22-5.51, p=0.01), and total duration of antibiotic therapy (AOR 1.14 95% CI 1.02-1.27, p=0.02). Conclusion: CDI is a relatively uncommon complication of CAP, occurring predominantly in elderly patients. Post CAP, it is, however, associated with increased in-hospital and 1 year mortality. Reducing total antibiotic exposure and duration of treatmentmight be as important as changing antibiotic class in reducing CDI rates.