Correlation of wbiI Genotype, Serotype, and Isolate Source within Species of the Burkholderia cepacia Complex

Abstract

Gram-negative bacteria of the Burkholderia cepacia complex (Bcc) are opportunistic pathogens that can infect the lungs of cystic fibrosis (CF) patients and can be transmitted among these patients, causing epidemics in the CF community. Lipopolysaccharide (LPS) is an important virulence factor of many gram-negative bacteria, with the O antigen component of LPS being responsible for serotype specificity. The goal of this work was to develop a genetic method of determining the serotype of Bcc isolates based on the conserved gene wbiI. Homologues of wbiI are found in polysaccharide biosynthesis gene clusters in other bacteria. Primers to a conserved region of the Bcc wbiI gene were able to amplify by PCR a single product in 67 of 80 Bcc isolates tested. Sequencing and restriction enzyme digestion of this wbiI PCR product revealed sufficient DNA polymorphisms to distinguish and group various isolates. In five of nine instances, Bcc isolates of a single serotype had a single wbiI restriction fragment length polymorphism (RFLP) pattern, while isolates of the other four serotypes could have multiple wbiI RFLP types. Species determination of the Bcc isolates revealed no obvious correlation between wbiI RFLP type and species. There was also no apparent correlation between wbiI RFLP type and the ability of a single Bcc isolate to infect an individual with CF. However three of five Bcc outbreaks involved isolates with the same wbiI RFLP type, indicating that wbiI RFLP typing may be a useful tool to help track Bcc outbreaks.

Phylogeographic, genomic, and meropenem susceptibility analysis of Burkholderia ubonensis

“…Unlike B . pseudomallei , where human-to-human transmission is exceptionally rare and where infections are almost always acquired from the environment [ 55 ], Bcc species can transmit between individuals, and indeed this a major clinical issue in the management of cystic fibrosis cohorts [ 56 ]. The selective forces acting upon Bcc strains in patients receiving meropenem or other antibiotics may encourage this phenotype to persist in the population, although the lack of human B .…”

Cepacia syndrome in cystic fibrosis: A systematic review of the literature and possible new perspectives in treatment

“…Another mechanism used by bacteria involves the activity of the alternative RNA polymerase extracytoplasmic sigma factor, an important regulator of the extracytoplasmic response that promotes the intracellular survival of B. cenocepacia , delaying phagolysosomal fusion in macrophages 26 . Furthermore, BCC forms biofilms, which can protect from both host defenses and antibiotics, and have a distinct lipopolysaccharide that has also been implicated in resistance to antibiotics and antimicrobial peptides 27 . In addition, BCC secretes a number of factors, such as catalases, proteases and siderophores, which can help BCC to evade the host's defenses 28 .…”

“…26 Furthermore, BCC forms biofilms, which can protect from both host defenses and antibiotics, and have a distinct lipopolysaccharide that has also been implicated in resistance to antibiotics and antimicrobial peptides. 27 In addition, BCC secretes a number of factors, such as catalases, proteases and siderophores, which can help BCC to evade the host's defenses. 28 However, the contribution of single factors to the overall virulence of BCC in CF remains to be better defined.…”