Chronic Burkholderia Research Articles

Study of human ribosomal gene complex in cystic fibrosis

Increasing the life expectancy of patients with CF is an urgent healthcare task all over the world. According to the Register of patients with cystic fibrosis in the Russian Federation (2020), the number of patients over 18 years of age is 26.5%. Assumably, cystic fibrosis can be used as a model of accelerated aging to study the aging process in general.Aim of the study was to analyze the number of rDNA copies in a sample of cystic fibrosis patients at different ages and with lethal outcome in relation to lung function, complications, and respiratory tract infections.Methods. We studied DNA samples isolated by the standard method from peripheral blood leukocytes of 277 patients diagnosed with cystic fibrosis. 998 DNA samples from healthy volunteers were used as a control group.Results. The study showed that the genomes of patients with CF contain more rDNA copies than those of control patients. The greatest number of copies of ribosomal genes was observed in DNA samples from deceased patients (p < 0.001) and was associated with more severe disease course. Among all CF patients, the largest number of rDNA copies in the genome was registered in patients with the lowest FEV1 values (less than 40%). It was found that patients with chronic Burkholderia cepacia complex infection had a significantly higher number of copies of ribosomal repeats than the total sample (p = 0.001) and the adults (p = 0.014). The number of ribosomal repeats did not differ between patients with other chronic respiratory tract infections.Conclusion. In the group of deceased patients, the patients with low respiratory function and Burkholderia cepacia complex infection had the highest number of rDNA copies in the genome, and the differences were significant. It can be assumed that the number of rDNA copies in the genome of CF patients is an additional prognostic marker that is associated with the patient’s life expectancy.

479: O-antigen loss is adaptive in early stages of chronic Burkholderia dolosa lung infection in cystic fibrosis

479: O-antigen loss is adaptive in early stages of chronic Burkholderia dolosa lung infection in cystic fibrosis

Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation.

Chronic pulmonary infection is a hallmark of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 18 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia. Burkholderia cepacia complex bacteria are resistant to many common antibiotics and able to acquire resistance against many more. Following patient segregation in cystic fibrosis medical care, the more virulent epidemic strains are not as frequent, and new infections are more likely to be with less virulent environmentally-acquired strains. Although evidence-based guidelines exist for treating respiratory exacerbations involving Pseudomonas aeruginosa, these cannot be extended to Burkholderia cepacia complex infections. This review, which is an update of a previous review, aims to assess the available trial evidence for the choice and application of treatments for these infections. To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation and chronically infected with organisms of the Burkholderia cepacia complex. We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of latest search: 29 May 2019. Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in people with cystic fibrosis chronically infected with organisms of the Burkholderia cepacia complex. No relevant trials were identified. No trials were included in this review. Burkholderia cepacia complex infections present a significant challenge for people with cystic fibrosis and their clinicians. The incidence is likely to increase as the cystic fibrosis population ages; and managing and treating these infections will become more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for people with cystic fibrosis who have chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each person individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. Multicentre randomised clinical trials are needed to assess the effectiveness of different antibiotic regimens in people with cystic fibrosis infected with organisms of the Burkholderia cepacia complex.

Risk factors associated with pulmonary exacerbations in pediatric patients with cystic fibrosis.

Cystic fibrosis patients develop pulmonary exacerbations (PEs) that require intravenous treatment. The objective of this study was to determine the risk factors associated with PEs and establish the percentage of patients who failed to recover their lung function. Observational, retrospective, cohort study. The medical records of cystic fibrosis patients seen at Hospital de Niños Ricardo Gutiérrez in 2013 were reviewed. Patients were divided into group 1, with PE (Fuchs criteria), and group 2, without PE. Age, sex, p.F508del mutation, percentage of baseline forced expiratory volume in the first second, baseline body mass index Z-score, chronic Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex colonization (Leeds criteria), percentage of cystic fibrosis-related diabetes, and recovery of baseline forced expiratory volume in the first second were recorded. A total of 117 patients were included. Group 1: 50, group 2: 67 patients. PEs were associated with a lower body mass index Z-score (RR: 1.45; p = 0.002), p.F508del mutation (RR: 3.23; p = 0.05), and chronic Burkholderia cepacia complex (RR: 3.69; p = 0.002), Pseudomonas aeruginosa (RR: 1.89; p = 0.01) and methicillinresistant Staphylococcus aureus colonization (RR: 2.32; p = 0.002). Twenty-four percent of patients failed to recover their lung function. The presence of the p.F508del mutation, a poor nutritional status, and chronic colonization were the risk factors for exacerbation. A fourth of patients failed to recover their lung function.

What matters in chronic Burkholderia cenocepacia infection in cystic fibrosis: Insights from comparative genomics.

Burkholderia cenocepacia causes severe pulmonary infections in cystic fibrosis (CF) patients. Since the bacterium is virtually untreatable by antibiotics, chronic infections persist for years and might develop into fatal septic pneumonia (cepacia syndrome, CS). To devise new strategies to combat chronic B. cenocepacia infections, it is essential to obtain comprehensive knowledge about their pathogenesis. We conducted a comparative genomic analysis of 32 Czech isolates of epidemic clone B. cenocepacia ST32 isolated from various stages of chronic infection in 8 CF patients. High numbers of large-scale deletions were found to occur during chronic infection, affecting preferentially genomic islands and nonessential replicons. Recombination between insertion sequences (IS) was inferred as the mechanism behind deletion formation; the most numerous IS group was specific for the ST32 clone and has undergone transposition burst since its divergence. Genes functionally related to transition metal metabolism were identified as hotspots for deletions and IS insertions. This functional category was also represented among genes where nonsynonymous point mutations and indels occurred parallelly among patients. Another category exhibiting parallel mutations was oxidative stress protection; mutations in catalase KatG resulted in impaired detoxification of hydrogen peroxide. Deep sequencing revealed substantial polymorphism in genes of both categories within the sputum B. cenocepacia ST32 populations, indicating extensive adaptive evolution. Neither oxidative stress response nor transition metal metabolism genes were previously reported to undergo parallel evolution during chronic CF infection. Mutations in katG and copper metabolism genes were overrepresented in patients where chronic infection developed into CS. Among professional phagocytes, macrophages use both hydrogen peroxide and copper for their bactericidal activity; our results thus tentatively point to macrophages as suspects in pathogenesis towards the fatal CS.

Clinical and microbiological profile of chronic Burkholderia cepacia complex infections in a cystic fibrosis reference hospital in Brazil.

Burkholderia sp. infections are extremely complex in cystic fibrosis (CF) patients, especially considering the lack of knowledge regarding its behavior, its relationship with prognosis, as well as its transmissibility and multidrug resistance features. This study evaluated the frequency of chronic infection by Burkholderia, using microbiological and clinical data. Ninety-eight patients with CF attended from July 2011 to April 2014 in a Brazilian reference hospital were included. Antimicrobial activity, molecular epidemiology, Shwachman score, body mass index, exacerbations, and lung function were analyzed. Nine patients had chronic colonization, and all of them showed preserved pulmonary function levels, body mass index, and Shwachman score. Meropenem was the most effective antibiotic; however, divergent results were shown by other studies. Cross-contamination may have occurred in only two unrelated patients of different ages, who were colonized by B. vietnamiensis, which does not occur frequently. Twelve new sequence types (STs) were identified and three STs have presented intercontinental distribution. None of the patients presented known epidemic strains. In conclusion, a relatively low number of patients with chronic colonization and suspected cross-infection were identified. Different from other studies that have found CF patients chronically colonized with Burkholderia sp. having a greater deterioration of lung function, more frequent antibiotic therapy, and increased mortality, in the current study, the patients showed good clinical outcomes and favorable options for antibiotics therapy. This study also updated the epidemiological database, which facilitates the multicentric collaborative analysis and assists in the control of global infection by these pathogens.

Pilot trial of tobramycin inhalation powder in cystic fibrosis patients with chronic Burkholderia cepacia complex infection

There is no effective chronic suppressive therapy Burkholderia cepacia complex infection in cystic fibrosis (CF) patients. This was a pilot, open-label clinical trial of tobramycin inhalation powder (TIP) delivered via Podhaler twice daily for 28days in adults and children with CF and chronic B. cepacia complex infection in Toronto, Canada. A total of 10 subjects (4 pediatric, 6 adult patients) were treated. There was a mean drop of 1.4 log (CFU/ml) in sputum bacterial density (p=0.01) and sputum IL-8 levels decreased significantly after 28days of TIP (p=0.04). The mean relative change in FEV1 (L) from Day 0 to Day 28 of TIP administration was a 4.6% increase but this was not statistically significant. The majority of patients (70%) had no or mild adverse events.

The art of persistence—the secrets toBurkholderiachronic infections

The Gram-negative proteobacteria genus Burkholderia encompasses multiple bacterial species that are pathogenic to humans and other vertebrates. Two pathogenic species of interest within this genus are Burkholderia pseudomallei (Bpm) and the B. cepacia complex (Bcc); the former is the causative agent of melioidosis in humans and other mammals, and the latter is associated with pneumonia in immunocompromised patients. One understudied and shared characteristic of these two pathogenic groups is their ability to persist and establish chronic infection within the host. In this review, we will explore the depth of knowledge about chronic infections caused by persistent Bpm and Bcc. We examine the host risk factors and immune responses associated with more severe chronic infections. We also discuss host adaptation and phenotypes associated with persistent Burkholderia species. Lastly, we survey how other intracellular bacteria associated with chronic infections are combatted and explore possible future applications to target Burkholderia Our goal is to highlight understudied areas that should be addressed for a more thorough understanding of chronic Burkholderia infections and how to combat them.

42 Dramatic clinical stabilisation following introduction of ivacaftor in an adult patient with cystic fibrosis (CF) and R117H/5T mutation

A 35-year-old man with CF and chronic Burkholderia cenocepacia complex (Genomovar IIIA) developed a progressive decline in lung function and general health over a three year period. FEV1 fell from 57% to 25% predicted with a median (range) CRP of 49 mg/L (24–134). Adherence to treatment was variable and his quality of life poor. He continued to decline despite 703 days of IV antibiotics between 02/2011 and 02/2015. CF was diagnosed at the age of 25 years through family screening. He had two siblings with CF, one of whom sadly passed away. The other sibling has started to show signs of deterioration. He is pancreatic sufficient with DF508/R117H mutations and 5T:9T alleles. In 02/2015 he was commenced on ivacaftor which resulted in a dramatic improvement in his general health and exercise tolerance. Sweat chloride fell from 90 to 59 mmol/l, lung function stabilised, BMI increased significantly and median (range) CRP fell to 27 (18.5–74). He was able to discontinue continuous intravenous antibiotic treatment by April 2015 and since then has only required one further course of treatment. His MRC breathlessness score has fallen from grade 4 to grade 2. Whilst ivacaftor has been approved for class III gating mutations it should also be considered for class IV R117H/5T mutations. In patients with severe lung disease, it appears to reduce sweat chloride, stabilise lung function, improve BMI and reduce the number of intravenous antibiotic courses (Ronan et al., J Cyst Fibros 2015:14; e4–5, Carter et al., Chest 2015:148; e72–5). Treatment of CF patients with milder phenotypes is likely to have significant long term benefit and protect against clinical deterioration

Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation.

Chronic pulmonary infection is a hallmark of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 18 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia. Burkholderia cepacia complex bacteria are resistant to many common antibiotics and able to acquire resistance against many more. Following patient segregation in cystic fibrosis medical care, the more virulent epidemic strains are not as frequent, and new infections are more likely to be with less virulent environmentally-acquired strains. Although evidence-based guidelines exist for treating respiratory exacerbations involving Pseudomonas aeruginosa, these cannot be extended to Burkholderia cepacia complex infections. This review, which is an update of a previous review, aims to assess the available trial evidence for the choice and application of treatments for these infections. To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation and chronically infected with organisms of the Burkholderia cepacia complex. We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of latest search: 28 August 2015. Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in people with cystic fibrosis chronically infected with organisms of the Burkholderia cepacia complex. No relevant trials were identified. No trials were included in this review. Burkholderia cepacia complex infections present a significant challenge for people with cystic fibrosis and their clinicians. The incidence is likely to increase as the cystic fibrosis population ages; and managing and treating these infections will become more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for people with cystic fibrosis who have chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each person individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. Multicentre randomised clinical trials are needed to assess the effectiveness of different antibiotic regimens in people with cystic fibrosis infected with organisms of the Burkholderia cepacia complex.

319 Nebulised temocillin for prophylaxis against Burkholderia vietnamiensis in an adult with cystic fibrosis

Objectives To illustrate the use of nebulised temocillin for prophylaxis in CF and chronic Burkholderia infection in a 29-year-old male. Methods Retrospective data collection from medical notes, included spirometry, CRP, frequency of IV antibiotics (14-day courses), and symptomatology. Data was collected for pre and post temocillin periods. Results Baseline spirometry: FEV1 66% pred., FVC 89% pred. Between ages 23 and 27 years, he had 2 courses of IV antibiotics yearly for exacerbations. FEV1 fell to a minimum of 55% pred., and CRP ( 100 on 3 occasions), and worsened spirometry (minimum FEV1 37% pred. and FVC 40% pred.). Worsening symptoms were recorded. Following onset of nebulised temocillin alternate months (7 months), frequency of IV antibiotics decreased to 4 courses (3 courses whilst off temocillin). Maximum CRP 42, and minimum FEV1 50% pred., significant symptom improvement was reported. Continuous nebulised temocillin was then started. No IV antibiotics were given in the following 4-month period. Conclusion Temocillin is a narrow spectrum penicillin stable to most β-lactamases and ESBLs. It demonstrates in vitro activity against B. cepacia . It does not induce β-lactamase production. Clinical data suggests benefit of IV temocillin for CF patients with B. cepacia . This case illustrates that temocillin may be a well tolerated and effective nebulised antibiotic for CF patients with Burkholderia .

92 Increasing virulence, acute phenotypic adaptations and evolving host–pathogen interactions during chronic Burkholderia cepacia complex infection of the cystic fibrosis lung

Objectives We aimed to define the phenotypic and genotypic adaptations that occur in the Burkholderia cepacia complex (BCC) during chronic infection of the cystic fibrosis (CF) lung. Methods We studied a total of 57 BCC isolates from 15 CF patients (2–6 isolates per patient), spanning infection periods ranging from 3 to 14 years. We assessed virulence using the Galleria mellonella model, and phenotypically characterized all isolates to determine how individual traits evolve during infection. Genome sequencing of selected early and late isolates provided insight into the genetic basis of the adaptations, whilst selected isolates were also studied in a murine infection model and in vitro macrophage model. Results Strikingly, during infection of 4 BCC-infected patients, the virulence of longitudinal isolates increased. Those patients were infected with either the B. cenocepacia ET-12 lineage (n = 3) or a B. multivorans outbreak strain (n = 1), both of which are linked with poor clinical outcome. Increasing virulence was uniformly correlated with increased haemolytic activity and decreased biofilm formation, consistent with the emergence of an ‘acute phenotype'. Late isolates displaying heightened virulence also exhibited altered host–pathogen interactions, with delayed clearance from Galleria and/or murine infection models, and reduced uptake by macrophages in vitro. Genome sequencing of isolates revealed evidence of convergent evolution, with comparable phenotypic adaptations arising through distinct genetic mutations. Conclusion BCC adaptation strategies within the CF lung differ from those observed in Pseudomonas aeruginosa , and may contribute to poor clinical outcome.

Inhaled aztreonam for chronic Burkholderia infection in cystic fibrosis: A placebo-controlled trial

Inhaled aztreonam for chronic Burkholderia infection in cystic fibrosis: A placebo-controlled trial

Inhaled aztreonam for chronic Burkholderia infection in cystic fibrosis: A placebo-controlled trial

Individuals with Burkholderia spp. infection have historically been excluded from efficacy trials of inhaled antibiotics, including aztreonam for inhalation solution (AZLI). A double-blind, placebo-controlled, 24-week trial of continuous AZLI/placebo treatment was undertaken in individuals with cystic fibrosis (CF) and chronic Burkholderia spp. infection. All subjects also received usual medical care (determined by their physicians). Additional antibiotic use was not restricted. Baseline FEV1% predicted values ranged from 15.8% to 114.6%. No significant treatment differences (AZLI vs. placebo) were observed at week 24 for any endpoints, including FEV1% predicted, number of respiratory exacerbations requiring systemic/inhaled antibiotics, or hospitalizations. Continuous AZLI administration was well tolerated. Burkholderia spp. susceptibility to antibiotics commonly used in CF therapy showed little change. 24-weeks of continuous AZLI treatment did not significantly improve lung function in CF subjects with chronic Burkholderia spp. infection. Non-study antibiotic use may have confounded any potential AZLI effects.

58 No antibiotic cross-resistance after 1 year of continuous aztreonam for inhalation solution (AZLI) in cystic fibrosis (CF) patients (pts) with chronic Burkholderia (BURK) infection

58 No antibiotic cross-resistance after 1 year of continuous aztreonam for inhalation solution (AZLI) in cystic fibrosis (CF) patients (pts) with chronic Burkholderia (BURK) infection

WS5.4 Aztreonam for inhalation solution (AZLI) in cystic fibrosis (CF) patients with chronic Burkholderia species (BURK) infection: final results from a randomized, placebo-controlled trial

WS5.4 Aztreonam for inhalation solution (AZLI) in cystic fibrosis (CF) patients with chronic Burkholderia species (BURK) infection: final results from a randomized, placebo-controlled trial

84 Aztreonam 75 mg powder and solvent for nebuliser solution (AZLI) in cystic fibrosis (CF) patients with chronic Burkholderia species (Burk) infection: baseline demographics and microbiology from a randomized, placebo-controlled trial

84 Aztreonam 75 mg powder and solvent for nebuliser solution (AZLI) in cystic fibrosis (CF) patients with chronic Burkholderia species (Burk) infection: baseline demographics and microbiology from a randomized, placebo-controlled trial

Development of novel animal infection models for the study of acute and chronic Burkholderia pseudomallei pulmonary infections

Burkholderia pseudomallei causes the disease melioidosis. The most common clinical presentation of melioidosis is pneumonia which can occur in acute and chronic forms. The tsunami of 2004 demonstrated a new risk factor for the acquisition of melioidosis and resulted in the proposal that direct delivery of B. pseudomallei into the lungs may result in the enhanced ability of this pathogen to cause disease. In the present studies, we present the development and characterization of rat models of acute and chronic pulmonary melioidosis, and we have utilized these models to demonstrate that direct delivery of B. pseudomallei into the lungs does indeed result in the enhanced ability of this pathogen to cause disease. Importantly, the rat lung infection models for melioidosis can quantify differences in virulence between individual B. pseudomallei wild type strains during both acute and chronic infections. Further, the histopathology associated with pulmonary melioidosis in the rat resembles that seen in tuberculosis. B. pseudomallei microarrays were used to characterize gene expression patterns during chronic pulmonary infections. Transcriptional profiling at several time points during chronic infection revealed that a wide range of genes associated with virulence and metabolic functions are differentially regulated in vivo during chronic infections.

Evidence of Coinfection with Distinct Strains of Burkholderia multivorans in a Cystic Fibrosis Patient

We report a Cystic Fibrosis patient with chronic Burkholderia multivorans infection involving persistency of one strain and temporary, consecutive coinfection with two different strains. Comparison of the colony morphology with the genotype revealed no correlation. These data are important for interpretation of clinical outcome and transmission studies in CF patients.