Clostridium difficile update

Dr. Vivian Loo, Director of Infection Control at the MUHC, has confirmed what staff and physicians in infection control and microbiology have long suspected — some of the Clostridium difficile strains that we have been seeing here at the MUHC and elsewhere in Quebec are similar to outbreaks in the U.S.

Tests undertaken at the Centers for Disease Control in Atlanta on samples sent by Dr. Loo indicate that the epidemic strain has an extra toxin known as binary toxin. The epidemic strain is also missing part of a gene that regulates toxins A and B that are normally produced by C. difficile. This gene deletion suggests that there's increased toxin production. These two factors may explain the virulence of some cases. Dr. Loo noted that identifying the particular strains is important in understanding the problem and developing precise measures to combat this pathogen.

For the last four periods starting in June, the number of cases of C. difficile at the MUHC has decreased dramatically to about 13 cases per 1,000 admissions. (The average across all Canadian hospitals is between five and ten cases per 1,000.) While there is a seasonal variation of decreased rates in the summer, possibly related to decreased antibiotic use, we have instituted a number of measures to combat the outbreak, including:

• Enhanced housekeeping activities
• Reducing the number of patients per room on units that have experienced persistent outbreaks
• Close monitoring of antibiotic use
• More dedicated equipment for all patients
• C. difficile diagnostic tests are available on a daily basis
• Patients exhibiting symptoms are immediately placed in isolation and treatment is initiated even before a diagnosis is confirmed
• Full isolation precautions for all ICU patients
• Information pamphlets provided to all patients at admission and at discharge
• Follow-up clinics within our infectious disease clinics at the RVH and the MGH for discharged patients
• Daily in-service support by our infection control specialists on affected wards

Although the downward trend is encouraging, Dr. Loo maintains that we must still remain vigilant in our control measures. With the coming winter season, the next several months will be the real test of whether the rates remain low.

(Reprinted from the MUHC Employee Newsletter, October 14, 2004 edition)