Higher rates of C. difficile detection attributed to better testing

By Charlie Fidelman, GAZETTE Health Reporter November 7, 2012

A sensitive diagnostic test implemented last year at the Royal Victoria Hospital is showing consistently higher rates of detection for a potentially fatal superbug than a test currently used at most Montreal hospitals, officials said Wednesday.

At least one surgery patient has spoken to The Gazette about being sent home from the Royal Victoria Hospital last month as a preventive measure because of an outbreak of Clostridium difficile, a bacterium that can cause damage to the bowel and lead to severe diarrhea in people at risk.

Charles Frenette, medical director of infection control at the McGill University Health Centre, said that while the centre is not facing an outbreak, it has been recording higher rates of C. difficile because its new test is 30 to 40 per cent more sensitive than the former.

“We’re one of the first ones in the province to use that test,” Frenette said of the PCR-based test, which directly targets the gene of the C. difficile toxin instead of looking for the toxin itself. Results are available the same day, while the previous test required an incubation period and up to three days for outcomes.

The MUHC was reporting about 10 cases per 10,000 patient days, and rates have gone up to about 15 cases per 10,000 with the new test, he explained.

“It’s much more sensitive than the previous tests we were using,” Frenette said, “so there are many patients that we are detecting now that we were not detecting before.”

He added that most hospitals are not using it because of its high cost — up to $30 per test.

Royal Victoria conducts such high-risk procedures as cardiac surgery and bone marrow, liver and kidney transplants, and patients often need antibiotics to treat their infections, Frenette said. About 60 to 80 per cent of patients end up on antibiotics because of their health conditions, he said.

“What we hope is that by finding more patients, we can isolate them sooner and prevent more transmission,” Frenette said.

Quebec has been keeping track of C. difficile-associated diarrhea in its hospitals since 2004, after an epidemic in health care facilities; 1,270 Quebecers died after contracting a virulent strain of the bacterium.

Rates of infection have decreased thanks to improved infection-control measures, but the superbug continues to be a problem for facilities.

Officials at the Montreal Health and Social Services Agency confirmed there are no reports of C. difficile outbreaks at any Montreal hospital, although there are always cases of infection because C. difficile bacteria and their spores are present in the feces of healthy people.