N-CDAD in Canada: results of the Canadian Nosocomial Infection Surveillance Program 1997 N-CDAD Prevalence Surveillance Project.

Background: A 1996 preproject survey among Canadian Hospital Epidemiology Committee (CHEC) sites revealed variations in the prevention, detection, management and surveillance of Clostridium difficile-associated diarrhea (CDAD). Facilities wanted to establish national rates of nosocomially acquired CDAD (N-CDAD) to understand the impact of control or prevention measures, and the burden of N-CDAD on health care resources. The CHEC, in collaboration with the Laboratory Centre for Disease Control (Health Canada) and under the Canadian Nosocomial Infection Surveillance Program, undertook a prevalence surveillance project among selected hospitals throughout Canada.

Objective: To establish national prevalence rates of N-CDAD.

Methods: For six weeks in 1997, selected CHEC sites tested all diarrheal stools from inpatients for either C difficile toxin or C difficile bacteria with evidence of toxin production. Questionnaires were completed for patients with positive stool assays who met the case definitions.

Results: Nineteen health care facilities in eight provinces participated in the project. The overall prevalence of N-CDAD was 13.0% (95% CI 9.5% to 16.5%). The mean number of N-CDAD cases were 66.3 cases/100,000 patient days (95% CI 37.5 to 95.1) and 5.9 cases/1000 patient admissions (95% CI 3.4 to 8.4). N-CDAD was found most frequently in older patients and those who had been hospitalized for longer than two weeks in medical or surgical wards.

Conclusions: This national prevalence surveillance project, which established N-CDAD rates, is useful as 'benchmark' data for Canadian health care facilities, and in understanding the patterns and impact of N-CDAD.