Characterization ofClostridium difficileStrains in British Columbia, Canada: A Shift from NAP1 Majority (2008) to Novel Strain Types (2013) in One Region
Background.Clostridium difficileis a major cause of gastrointestinal illness. Epidemic NAP1 strains contain toxins A and B, a deletion in repressortcdC, and a binary toxin.Objectives. To determine the molecular epidemiology ofC. difficilein British Columbia and compare between two time points in one region.Methods.C. difficileisolates from hospital and community laboratories (2008) and one Island Health hospital laboratory (2013) were characterized by pulsed-field gel electrophoresis, PCR-ribotyping, toxin possession,tcdCgenotype, and antimicrobial susceptibility.Results. In 2008, 42.7% of isolates had NAP1 designation. Hospital-collected isolates were associated with older patients and more NAP1 types. Unlike other isolates, most NAP1 isolates possessed binary toxin and a 19 bp loss intcdC. All isolates were susceptible to metronidazole and vancomycin. A 2013 follow-up revealed a 28.9% decrease in NAP1 isolates and 20.0% increase in isolates without NAP designation in one region. Then, community-associated cases were seen in younger patients, while NAP types were evenly distributed. Isolates without NAP designation did not cluster with a PFGE pattern or ribotype.Conclusions. Evaluation ofC. difficileinfections within British Columbia revealed demographic associations, epidemiological shifts, and characteristics of strain types. Continuous surveillance ofC. difficilewill enable detection of emerging strains.