Phenotypic diversity and genotypic flexibility of during long-term chronic infection of cystic fibrosis lungs.

Chronic bacterial infections of the lung are the leading cause of morbidity and mortality in cystic fibrosis patients. Tracking bacterial evolution during chronic infections can provide insights into how host selection pressures-including immune responses and therapeutic interventions-shape bacterial genomes. We carried out genomic and phenotypic analyses of 215 serially collected isolates from 16 cystic fibrosis patients, spanning a period of 2-20 yr and a broad range of epidemic lineages.

Long-Term Evolution of during a Chronic Cystic Fibrosis Infection Reveals Shifting Forces of Selection.

is an opportunistic pathogen capable of causing severe disease in patients with cystic fibrosis (CF). Patients may be chronically infected for years, during which the bacterial population evolves in response to unknown forces. Here we analyze the genomic and functional evolution of a infection that was sequentially sampled from a CF patient over 20 years.

Whole-Genome Sequencing of Three Clonal Clinical Isolates of B. cenocepacia from a Patient with Cystic Fibrosis.

Burkholderia cepacia complex bacteria are amongst the most feared of pathogens in cystic fibrosis (CF). The BCC comprises at least 20 distinct species that can cause chronic and unpredictable lung infections in CF. Historically the species B.

Activity of Tobramycin against Cystic Fibrosis Isolates of Burkholderia cepacia Complex Grown as Biofilms.

Pulmonary infection with Burkholderia cepacia complex in cystic fibrosis (CF) patients is associated with more-rapid lung function decline and earlier death than in CF patients without this infection. In this study, we used confocal microscopy to visualize the effects of various concentrations of tobramycin, achievable with systemic and aerosolized drug administration, on mature B. cepacia complex biofilms, both in the presence and absence of CF sputum.

Cystic fibrosis-adapted quorum sensing mutants cause hyperinflammatory responses.

Cystic fibrosis lung disease is characterized by chronic airway infections with the opportunistic pathogen and severe neutrophilic pulmonary inflammation. undergoes extensive genetic adaptation to the cystic fibrosis (CF) lung environment, and adaptive mutations in the quorum sensing regulator gene commonly arise. We sought to define how mutations in alter host-pathogen relationships.

Burkholderia species infections in patients with cystic fibrosis in British Columbia, Canada. 30 years' experience.

Rationale: We have been collecting Burkholderia species bacteria from patients with cystic fibrosis (CF) for the last 30 years. During this time, our understanding of their multispecies taxonomy and infection control has evolved substantially.

Objectives: To evaluate the long-term (30 year) epidemiology and clinical outcome of Burkholderia infection in CF, and fully define the risks associated with infection by each species.

In vitro efficacy of high-dose tobramycin against Burkholderia cepacia complex and Stenotrophomonas maltophilia isolates from cystic fibrosis patients.

Burkholderia cepacia complex and Stenotrophomonas maltophilia infections are associated with poor clinical outcomes in persons with cystic fibrosis (CF). The MIC50 based on planktonic growth and the biofilm concentration at which 50% of the isolates tested are inhibited (BIC50) of tobramycin were measured for 180 B. cepacia complex and 101 S.

Swimming motility in a longitudinal collection of clinical isolates of Burkholderia cepacia complex bacteria from people with cystic fibrosis.

Chronic bacterial lung infections in cystic fibrosis (CF) are the leading cause of morbidity and mortality. While a range of bacteria are known to be capable of establishing residence in the CF lung, only a small number have a clearly established link to deteriorating clinical status. The two bacteria with the clearest roles in CF lung disease are Pseudomonas aeruginosa and bacteria belonging to the Burkholderia cepacia complex (BCC).

Fosmidomycin decreases membrane hopanoids and potentiates the effects of colistin on Burkholderia multivorans clinical isolates.

Burkholderia cepacia complex (Bcc) pulmonary infections in people living with cystic fibrosis (CF) are difficult to treat because of the extreme intrinsic resistance of most isolates to a broad range of antimicrobials. Fosmidomycin is an antibacterial and antiparasitic agent that disrupts the isoprenoid biosynthesis pathway, a precursor to hopanoid biosynthesis. Hopanoids are involved in membrane stability and contribute to polymyxin resistance in Bcc bacteria.

The mucoid switch in Pseudomonas aeruginosa represses quorum sensing systems and leads to complex changes to stationary phase virulence factor regulation.

The opportunistic pathogen Pseudomonas aeruginosa chronically infects the airways of Cystic Fibrosis (CF) patients during which it adapts and undergoes clonal expansion within the lung. It commonly acquires inactivating mutations of the anti-sigma factor MucA leading to a mucoid phenotype, caused by excessive production of the extracellular polysaccharide alginate that is associated with a decline in lung function. Alginate production is believed to be the key benefit of mucA mutations to the bacterium in the CF lung.

Pseudomonas aeruginosa enhances production of a non-alginate exopolysaccharide during long-term colonization of the cystic fibrosis lung.

The gram-negative opportunistic pathogen Pseudomonas aeruginosa is the primary cause of chronic respiratory infections in individuals with the heritable disease cystic fibrosis (CF). These infections can last for decades, during which time P. aeruginosa has been proposed to acquire beneficial traits via adaptive evolution.

Developing an international Pseudomonas aeruginosa reference panel.

Pseudomonas aeruginosa is a major opportunistic pathogen in cystic fibrosis (CF) patients and causes a wide range of infections among other susceptible populations. Its inherent resistance to many antimicrobials also makes it difficult to treat infections with this pathogen. Recent evidence has highlighted the diversity of this species, yet despite this, the majority of studies on virulence and pathogenesis focus on a small number of strains.

Total protein extraction and 2-D gel electrophoresis methods for Burkholderia species.

The investigation of the intracellular protein levels of bacterial species is of importance to understanding the pathogenic mechanisms of diseases caused by these organisms. Here we describe a procedure for protein extraction from Burkholderia species based on mechanical lysis using glass beads in the presence of ethylenediamine tetraacetic acid and phenylmethylsulfonyl fluoride in phosphate buffered saline. This method can be used for different Burkholderia species, for different growth conditions, and it is likely suitable for the use in proteomic studies of other bacteria.

Burkholderia pseudomultivorans sp. nov., a novel Burkholderia cepacia complex species from human respiratory samples and the rhizosphere.

Eleven Burkholderia cepacia-like isolates of human clinical and environmental origin were examined by a polyphasic approach including recA and 16S rRNA sequence analysis, multilocus sequence analysis (MLSA), DNA base content determination, fatty acid methyl ester analysis, and biochemical characterization. The results of this study demonstrate that these isolates represent a novel species within the B. cepacia complex (Bcc) for which we propose the name Burkholderia pseudomultivorans.

Metabolite profiling to characterize disease-related bacteria: gluconate excretion by Pseudomonas aeruginosa mutants and clinical isolates from cystic fibrosis patients.

Metabolic footprinting of supernatants has been proposed as a tool for assigning gene function. We used NMR spectroscopy to measure the exometabolome of 86 single-gene transposon insertion mutant strains (mutants from central carbon metabolism and regulatory mutants) of the opportunistic pathogen Pseudomonas aeruginosa, grown on a medium designed to represent the nutritional content of cystic fibrosis sputum. Functionally related genes had similar metabolic profiles.

Serum susceptibility in clinical isolates of Burkholderia cepacia complex bacteria: development of a growth-based assay for high throughput determination.

Burkholderia cepacia complex (BCC) bacteria can cause devastating chronic infections in people with cystic fibrosis. Of particular concern is "cepacia syndrome," a rapidly progressive and usually fatal decline in health, characterized by a necrotizing bacteremic pneumonia. An important component of defense against bloodstream infections is the bactericidal action of serum.

In vitro susceptibility of Burkholderia vietnamiensis to aminoglycosides.

Burkholderia cepacia complex (BCC) bacteria are opportunistic pathogens that can cause severe disease in cystic fibrosis (CF) patients and other immunocompromised individuals and are typically multidrug resistant. Here we observed that unlike other BCC species, most environmental and clinical Burkholderia vietnamiensis isolates were intrinsically susceptible to aminoglycosides but not to cationic antimicrobial peptides or polymyxin B. Furthermore, strains acquired aminoglycoside resistance during chronic CF infection, a phenomenon that could be induced under tobramycin or azithromycin pressure in vitro.

Functional quorum sensing systems are maintained during chronic Burkholderia cepacia complex infections in patients with cystic fibrosis.

Quorum sensing (QS) contributes to the virulence of Pseudomonas aeruginosa and Burkholderia cepacia complex lung infections. P. aeruginosa QS mutants are frequently isolated from patients with cystic fibrosis.

Parallel evolution in Pseudomonas aeruginosa over 39,000 generations in vivo.

The Gram-negative bacterium Pseudomonas aeruginosa is a common cause of chronic airway infections in individuals with the heritable disease cystic fibrosis (CF). After prolonged colonization of the CF lung, P. aeruginosa becomes highly resistant to host clearance and antibiotic treatment; therefore, understanding how this bacterium evolves during chronic infection is important for identifying beneficial adaptations that could be targeted therapeutically.

Mucoid and nonmucoid Burkholderia cepacia complex bacteria in cystic fibrosis infections.

Rationale: infection with Burkholderia cepacia complex (BCC) bacteria in cystic fibrosis (CF) is associated with an unpredictable rate of pulmonary decline. Some BCC, but not others, elaborate copious mucoid exopolysaccharide, endowing them with a gross mucoid phenotype, the clinical significance of which has not been described.

Objectives: to determine whether there was a correlation between bacterial mucoid phenotype, as assessed in a semiquantitative manner from plate culture, and severity of disease as assessed by the rate of decline in lung function.

The role of mucoidy in virulence of bacteria from the Burkholderia cepacia complex: a systematic proteomic and transcriptomic analysis.

Bacteria of the Burkholderia cepacia complex (BCC) are associated with severe infection in cystic fibrosis. Recent evidence shows that the mucoid phenotype is common in BCC bacteria; however, during chronic infection, transitions from the mucoid to nonmucoid morphology have been shown to take place. Here we use RNA microarray and proteomic isobaric tagging relative and absolute quantitation technologies to gain insight into a pair of mucoid and nonmucoid isolates of B.

Hypertonic Saline Therapy in Cystic Fibrosis: Do Population Shifts Caused by the Osmotic Sensitivity of Infecting Bacteria Explain the Effectiveness of this Treatment?

Cystic fibrosis (CF) is caused by a defect in the CF transmembrane regulator that leads to depletion and dehydration of the airway surface liquid (ASL) of the lung epithelium, providing an environment that can be infected by bacteria leading to increased morbidity and mortality. Pseudomonas aeruginosa chronically infects more than 80% of CF patients and one hallmark of infection is the emergence of a mucoid phenotype associated with a worsening prognosis and more rapid decline in lung function. Hypertonic saline (HS) is a clinically proven treatment that improves mucociliary clearance through partial rehydration of the ASL of the lung.

Bacteria of the Burkholderia cepacia complex are cyanogenic under biofilm and colonial growth conditions.

Background: The Burkholderia cepacia complex (Bcc) is a collection of nine genotypically distinct but phenotypically similar species. They show wide ecological diversity and include species that are used for promoting plant growth and bio-control as well species that are opportunistic pathogens of vulnerable patients. Over recent years the Bcc have emerged as problematic pathogens of the CF lung.

Differential mucoid exopolysaccharide production by members of the Burkholderia cepacia complex.

We demonstrate that all nine species of the Burkholderia cepacia complex can express the mucoid phenotype. A survey of clinical isolates showed that strains of B. cenocepacia, the most virulent species of the complex, are most frequently nonmucoid.