Disproportionate Distribution of Burkholderia cepacia Complex Species and Transmissibility Markers in Cystic Fibrosis

Abstract

Several distinct species (genomovars) comprise bacteria previously identified merely as Burkholderia cepacia. Understanding how these species, collectively referred to as the B. cepacia complex, differ in their epidemiology and pathogenic potential in cystic fibrosis (CF) is important in efforts to refine management strategies. B. cepacia isolates recovered from 606 CF patients receiving care at 132 treatment centers in 105 cities in the United States were assessed to determine species within the B. cepacia complex and examined for the presence of putative transmissibility markers (B. cepacia epidemic strain marker [BCESM] and cable pilin subunit gene [cblA]). Fifty percent of patients were infected with B. cepacia complex genomovar III, 38% with B. multivorans (formerly genomovar II), and 5% with B. vietnamiensis (formerly genomovar V); fewer than 5% of patients were infected with either genomovar I, B. stabilis (formerly genomovar IV), genomovar VI, or genomovar VII. BCESM was found in 46% of genomovar III isolates and not in any other species. Only one isolate, from a patient infected with the ET12 epidemic lineage, contained the complete cblA pilin subunit gene. Our data indicate a differential capacity for human infection among the phylogenetically closely related species of the B. cepacia complex. The low frequency of BCESM and cblA suggests that they are not sufficient markers of B. cepacia virulence or transmissibility.

Evaluation of species-specific recA-based PCR tests for genomovar level identification within the Burkholderia cepacia complex

“…However, it was apparent that not all B. cepacia strains have the same capacity for epidemic cross-infection or are capable of causing fatal pneumonia [8,12,13]. Taxonomic studies have revealed that B. cepacia consists of a group of at least five phenotypically similar and closely related genomic species (B. cepacia genomovars I-V), which has become known as the B. cepacia complex [14].…”

“…Although all B. cepacia genomovars can colonise CF patients, the large majority of infections is caused by B. multivorans or B. cepacia genomovar III [12,13,27]. The aim of the present study was to evaluate the sensitivity and specificity of recA-based PCR tests for the identification of these B. cepacia genomovars and of PCR tests for B. cepacia genomovar I and B. ambifaria.…”

Comparason of extraction methods for PCR detection of Burkholderia cepacia complex (BCC) from cystic fibrosis patients

“…Laboratory identification of BCC up to genomovar level is also crucial since certain genomovars are reported to be highly transmissible between CF patients and stringent infection control policies should be undertaken to prevent transmission to other patients [1,8,11]. The discrepancy between results obtained by phenotypic and molecular detection techniques is also of importance for the identification of BCC.…”

Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides

“…cenocepacia and Burkholderia multivorans are the most frequently isolated Bcc species from CF patients (Govan et al, 2007;LiPuma, 2005;Reik et al, 2005). B. cenocepacia accounts for most transmissible strains, although transmissible strains of B. multivorans and Burkholderia dolosa have also been reported in some CF centres (Biddick et al, 2003;LiPuma et al, 2001;McDowell et al, 2004;Speert et al, 2002). CF patients infected with B. cenocepacia have a much lower success rate after lung transplantation compared to CF patients infected with other Bcc species or not infected with Bcc (Alexander et al, 2008;Murray et al, 2008).…”