Epidemiology of Burkholderia cepacia complex in patients with cystic fibrosis, Canada

Abstract

The Burkholderia cepacia complex is an important group of pathogens in patients with cystic fibrosis (CF). Although evidence for patient-to-patient spread is clear, microbial factors facilitating transmission are poorly understood. To identify microbial clones with enhanced transmissibility, we evaluated B. cepacia complex isolates from patients with CF from throughout Canada. A total of 905 isolates from the B. cepacia complex were recovered from 447 patients in 8 of the 10 provinces; 369 (83%) of these patients had genomovar III and 43 (9.6%) had B. multivorans (genomovar II). Infection prevalence differed substantially by region (22% of patients in Ontario vs. 5% in Quebec). Results of typing by random amplified polymorphic DNA analysis or pulsed-field gel electrophoresis indicated that strains of B. cepacia complex from genomovar III are the most potentially transmissible and that the B. cepacia epidemic strain marker is a robust marker for transmissibility.

Figure

Phylogenetic analysis of the recA gene from the Burkholderia cepacia complex. The phylogenetic diversity of the B. cepacia complex observed after nucleotide sequence analysis of the recA gene is shown. Isolates recovered from Canadian CF patients that are representative of strains of currently indeterminate genomovar status (Table 2) appear in bold and lack species identification; all fall within the current B. cepacia complex. The tree was drawn as described (16). The recA sequence from Bordetella pertussis was used as a root, and the genetic distance is indicated by the bar.