Organisms of the Burkholderia cepacia complex are especially important pathogens in cystic fibrosis (CF), with a propensity for patient-to-patient spread and long-term respiratory colonization. B. cenocepacia and Burkholderia multivorans account for the majority of infections in CF, and major epidemic clones have been recognized throughout the world. The aim of the present study was to develop and evaluate a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) scheme for B. cenocepacia. Potential VNTR loci were identified upon analysis of the annotated genome sequences of B. cenocepacia strains AU1054, J2315, and MCO-3, and 10 of them were selected on the basis of polymorphisms and size. A collection of 100 B. cenocepacia strains, including epidemiologically related and unrelated strains, as well as representatives of the major epidemic lineages, was used to evaluate typeability, epidemiological concordance, and the discriminatory power of MLVA-10 compared with those of pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Longitudinal stability was assessed by testing 39 successive isolates from 14 patients. Typeability ranged from 0.91 to 1, except for that of one marker, which was not amplified in 53% of the B. cenocepacia IIIA strains. The MLVA types were shown to be stable in chronically colonized patients and within outbreak-related strains, with excellent epidemiological concordance.
The Burkholderia cepacia complex (BCC), which includes 18 closely related species, is mainly involved in pulmonary infections in patients with cystic fibrosis (CF), although it is also occasionally recovered in nosocomial infections and/or from immunocompromised hosts. BCC infection in CF patients is associated with accelerated decline of lung function, cepacia syndrome, and poor posttransplantation outcome. The most frequently recovered species of the BCC are B. cenocepacia and Burkholderia multivorans, which have been found to be responsible for large outbreaks among CF patients, prompting the implementation of infection control measures and epidemiological surveillance. B. cenocepacia consists of four recA subgroups: IIIA, which includes the Edinburgh-Toronto electrophoretic type 12 (ET-12) epidemic lineage (in Canada and the United Kingdom) (1); IIIB, which includes the PHDC epidemic lineage (in the United States) (2) and the Midwest clone (3); IIIC, which is exclusively environmental; and IIID, which was reported to be responsible for 50% of the BCC infections in an Italian CF center (4).Putative transmissibility markers have been identified within B. cenocepacia epidemic strains. The cblA pilin gene is characteristic of ET-12 strains (5). The B. cepacia epidemic strain marker (BCESM), which is part of a pathogenicity island, was identified in ET-12 strains and in other epidemic lineages but also in unique clinical or environmental strains (6, 7), whereas the PHDC lineage is BCESM negative. Finally, the IS1363 insertion sequence was demonstrated to be characteristic of the PHDC and ET...
