Emergence and Molecular Characterization of NAP4 Clostridium difficile Healthcare-Associated Infections in Canada
Clostridium difficile is an important nosocomial pathogen and the leading cause of antibiotic-associated diarrhea. In the early 2000's, major outbreaks of C. difficile occurred in the Canada and the United States, both caused by the same strain, the North American Pulsed-Field type 1 (NAP1). Recently a steady rise in prevalence of a NAP4 strain was observed. This study utilized phenotypic and genotypic methods, including whole genome sequencing, to fully characterize and better understand the emergence of NAP4 in Canada. Through WGS it was revealed that an emerging NAP4 PFGE type (PFGE type 0033) has acquired a novel phage (phiCD505), which harbors transcriptional regulators and is inserted in close proximity to a GMP synthase gene. The role of these phage encoded transcriptional regulators on C. difficile virulence factors and/or disruption of normal expression of GMP synthase remain to be elucidated, but might be contributing to the emergence of this PFGE type.