Epidemiology of Clostridium species bacteremia in Calgary, Canada, 2000-2006

Summary Objectives To define the incidence, risk factors for acquisition, and outcomes associated with clostridial bacteremia in a large Canadian health region. Methods Retrospective population-based surveillance for clostridial bacteremia was conducted among all residents of the Calgary Health Region (population 1.2 million) during 2000–2006. Results One hundred and thirty-eight residents had incident Clostridium species bacteremia (1.8 per 100,000/year); 45 (33%) were nosocomial, 55 (40%) were healthcare-associated community onset, and 38 (28%) were community acquired. Older age and a number of underlying conditions were risk factors for acquiring Clostridium species bacteremia most importantly hemodialysis [relative risk (RR) 212.3; 95% confidence interval (CI) 106.5–385.5], malignancy (RR 40.2; 95% CI 27.6–58.1), and Crohn's disease (RR 11.2; 95% CI 3.0–29.4). Clostridium perfringens was most commonly identified with 58 (42%) isolates followed by Clostridium septicum (19; 14%), Clostridium ramosum (13; 9%), Clostridium clostridiiforme (8; 6%), and Clostridium difficile (7; 5%). Reduced susceptibility to penicillin occurred in 14/135 (10%), to metronidazole in 2/135 (1%), and to clindamycin in 36/135 (27%) isolates. The median length of stay was 12.7 days and 39/130 (30%) patients died in hospital for mortality rate of 0.5 per 100,000/year. Conclusions Clostridium species bacteremia is associated with a significant burden of illness and hemodialysis and cancer patients are at highest risk.