We have previously shown differences in virulence between species of the Burkholderia cepacia complex using the alfalfa infection model and the rat agar bead chronic infection model. Burkholderia cenocepacia strains were more virulent in these two infection models than Burkholderia multivorans and Burkholderia stabilis strains. In order to identify genes that may account for the increased virul...

The nematode Caenorhabditis elegans may be killed by certain pathogenic bacteria and thus is a model organism for studying interactions between bacteria and animal hosts. However, growing nematodes on prey bacteria may influence their susceptibility to potential pathogens. A method of axenic nematode culture was developed to isolate and quantify interactions between C. elegans and potentially p...

Whole cells and lipopolysaccharides (LPSs) extracted from Burkholderia cepacia, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli were compared in their ability to stimulate tumor necrosis factor alpha (TNF-alpha) from the human monocyte cell line MonoMac-6. B. cepacia LPS, on a weight-for-weight basis, was found to have TNF-alpha-inducing activity similar to that of LP...

Burkholderia cepacia is an opportunistic pathogen that causes severe systemic infections in patients with chronic granulomatous disease (CGD) or with cystic fibrosis (CF), but its mechanisms of virulence are poorly understood. We developed a murine model of systemic infection in wild-type (WT) and gamma interferon knockout (GKO) BALB/c mice to facilitate dissection of components of pathogenicit...

Letters toxicity, no antidiphtheria serum was administered. The patient became well and was discharged on day 4. In the first case, a throat culture could not be done because the patient had already received local antiseptic paint. However, the diagnosis was clinically consistent with classic diphtheria with features of toxicity. In the second case, diphtheria was suspected only after bacteriol...

Burkholderia cepacia is an important pathogen in patients with cystic fibrosis (CF) and much is now known of its epidemiology. In contrast, its virulence mechanisms are poorly understood. The lipopolysaccharide (LPS) of B. cepacia, a well-recognised virulence factor of other gram-negative bacteria, is known to be strongly endotoxic in vitro. The aim of this study was to observe if there were an...

Gram-negative Burkholderia cepacia complex (Bcc) isolates were screened for antimicrobial activity against cystic fibrosis microbial pathogens, and the ability of B. ambifaria to inhibit B. multivorans was identified. The activity was mapped to a cluster of cryptic, quorum-sensing-regulated modular polyketide synthase (PKS) genes. Enacyloxin IIa and its stereoisomer designated iso-enacyloxin II...

Azithromycin and clarithromycin were paired with other antibiotics to test synergistic activity against 300 multidrug-resistant pathogens isolated from cystic fibrosis (CF) patients. Clarithromycin-tobramycin was most active against Pseudomonas aeruginosa and inhibited 58% of strains. Azithromycin-trimethoprim-sulfamethoxazole, azithromycin-ceftazidime, and azithromycin-doxycycline or azithromy...

This work reports the biochemical and functional analysis of the Burkholderia cenocepacia J2315 bceN gene, encoding a protein with GDP-D-mannose 4,6-dehydratase enzyme activity (E.C.4.2.1.47). Data presented indicate that the protein is active when in the tetrameric form, catalyzing the conversion of GDP-D-mannose into GDP-4-keto-6-deoxy-D-mannose. This sugar nucleotide is the intermediary nece...

A single multilocus sequence typing (MLST) scheme was developed for precise characterization of the opportunistic pathogens of Burkholderia cepacia complex (BCC), a group composed of at least nine closely related species. Seven conserved housekeeping genes were selected after a comparison of five Burkholderia species, and a collection of strains was subjected to nucleotide sequence analysis usi...