Friday, December 02, 2005

Clostridium difficile: the Quebec strain

DB blogged about a new face of C-diff earlier today—it’s been showing up in healthy members of the community, some of whom had no recent antibiotic exposure. There’s another aspect that is worth our attention and that’s the Quebec strain.

A hypervirulent strain of C. difficile has emerged there over the last three years. A study of the attributable mortality, an editorial and a news piece appear in the October issue of CMAJ.

What’s different about the strain? As reported in these articles: 1) it produces 15-20 times the amount of toxin as the ordinary strains, due to an altered repressor gene; 2) it’s more lethal, with 23% of patients dead at 30 days and an attributable mortality at one year of 16.7%.

The author of the study points out that some patients appear to have died of direct complications of the infection such as shock or perforation while others succumbed to secondary events such as myocardial infarction, venous thromboembolism or secondary infection.

Infection control implications are discussed and the papers offer conjecture about risk factors at the Quebec hospitals. There was no difference in patient characteristics compared to other regions of Canada or the United States (the strain has shown up at a few locations in the US), and no evident difference in the use of antibiotics. The only common thread seemed to be the use of shared bathrooms. The authors conclude: The lack of investment in our hospitals infrastructure over several decades, with shared bathrooms being the rule rather than the exception, may have facilitated the transmission of this spore-forming pathogen, which can survive on environmental surfaces for months. Providing modern medical care within hospitals built a century ago is no longer acceptable.

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