Survey of incidence of Clostridium difficile infection in Canadian hospitals and diagnostic approaches

Abstract

A questionnaire relating to Clostridium difficile disease incidence and diagnostic practices was sent to 380 Canadian hospitals (all with > 50 beds). The national questionnaire response rate was 63%. In-house testing was performed in 17.6, 61.5, and 74.2% of the hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average test positivity rates were 17.2, 15.3, and 13.2% for hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average disease incidences were 23.5, 30.8, and 40.3 cases per 100,000 patient days in the hospitals with < 300, 300 to 500, and > 500 beds, respectively. In the 81 hospitals where in-house testing was performed, cytotoxin testing utilizing tissue culture was most common (44.4%), followed by enzyme-linked immunosorbent assay (38.3%), culture for toxigenic C. difficile (32.1%), and latex agglutination (13.6%). The clinical criteria for C. difficile testing were variable, with 85% of hospitals indicating that a test was done automatically if ordered by a doctor. Our results show that C. difficile-associated diarrhea is a major problem in hospitals with > or = 200 beds. Despite a lower disease incidence in smaller hospitals, there was a higher diagnostic test positivity rate. This may reflect the preference of smaller hospitals for culture and latex agglutination tests.

FIG. 1

Specimen processing and test positivity rates stratified according to hospital size (number of beds). A total of 81 hospitals performed in-house testing. Some hospitals referred specimens out for diagnostic testing. Data on the volume of specimens processed and test positivity rates was not provided by all hospitals.

FIG. 2

C. difficile-associated diarrhea rates. Data is stratified according to hospital size (number of beds). C. difficile-associated diarrhea rates are expressed as the number of cases per 100,000 patient days and per 1,000 patient admissions.

FIG. 3

National C. difficile disease incidence rates. Asterisks indicate that data on disease incidence from hospitals having fewer than 200 beds were excluded. Data on disease incidence was not available for Newfoundland. Data on disease incidence per 100,000 patient days was not available for Saskatchewan. The numbers above the bars are the numbers of respondents.

FIG. 4

C. difficile testing methods for tertiary care versus general medicine hospitals. Responses were obtained from 43 tertiary care hospitals and 31 general medicine hospitals.