Burkholderia cepacia complex infection in adult patients with cystic fibrosis—is early eradication possible?

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute infection with Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective. This is an updated version of the review.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

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.Last search: 12 March 2019.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 12 March 2019.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics or alternative therapeutic agents used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 52 studies (79 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute of Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective. This is an updated version of the review.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

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.Last search: 14 July 2016.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 14 July 2016.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics or alternative therapeutic agents used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 50 studies (70 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Two case reports of the successful eradication of new isolates of Burkholderia cepacia complex in children with cystic fibrosis

Background

Chronic infection with Burkholderia cepacia complex (BCC) has a detrimental effect on morbidity and mortality for patients with cystic fibrosis (CF). It is therefore logical to attempt to eradicate new isolates however there is a paucity of information to guide treatment. We report the successful eradication of new isolates of BCC in two children with CF.

Case presentation

Burkholderia cepacia was successfully eradicated in a 14 year old boy with CF and Burkholderia gladioli was successfully eradicated in a six year old girl with CF. In both children two weeks of intravenous (IV) tobramycin, ceftazidime and temocillin were used followed by three months of inhaled tobramycin. Bronchoalveolar lavage samples taken during flexible bronchoscopy were used prior to treatment to exclude spontaneous clearance as well as after treatment to confirm eradication.

Conclusions

New isolates of BCC can be successfully eradicated in children with CF. More research is urgently required in this area to identify the best treatment regimen for BCC eradication.

Clinical and in vitro evidence for the antimicrobial therapy in Burkholderia cepacia complex infections

Treatment of infections caused by Burkholderia cepacia complex (Bcc) in cystic fibrosis (CF) patients poses a complex problem. Bcc is multidrug-resistant due to innate and acquired mechanisms of resistance. As CF patients receive multiple courses of antibiotics, susceptibility patterns of strains from CF patients may differ from those noted in strains from non-CF patients. Thus, there was a need for assessing in vitro and clinical data to guide antimicrobial therapy in these patients. A systematic search of literature, followed by extraction and analysis of available information from human and in vitro studies was done. The results of the analysis are used to address various aspects like use of antimicrobials for pulmonary and non-pulmonary infections, use of combination versus monotherapy, early eradication, duration of therapy, route of administration, management of biofilms, development of resistance during therapy, pharmacokinetics-pharmacodynamics correlations, therapy in post-transplant patients and newer drugs in Bcc-infected CF patients.

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute of Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

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.Last search: 13 January 2014.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 28 November 2013.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 43 studies (61 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Growth on mannitol-rich media elicits a genome-wide transcriptional response in Burkholderia multivorans that impacts on multiple virulence traits in an exopolysaccharide-independent manner

In common with other members of the Burkholderia cepacia complex (BCC), Burkholderia multivorans is capable of producing exopolysaccharide (EPS) when grown on certain mannitol-rich media. The significance of the resulting mucoid phenotype and the genome-wide response to mannitol has never been characterized despite its clinical relevance following the approval of a dried-powder preparation of mannitol as an inhaled osmolyte therapy for cystic fibrosis (CF) patients. In the present study we defined the transcriptional response of B. multivorans ATCC 17616, a model genome-sequenced strain of environmental origin, to growth on mannitol-rich yeast extract media (MYEM). EPS-dependent and -independent impact of MYEM on virulence-associated traits was assessed in both strain ATCC 17616 and the CF isolate B. multivorans C1576. Our studies revealed a significant transcriptional response to MYEM encompassing approximately 23 % of predicted genes within the genome. Strikingly, this transcriptional response identified that EPS induction occurs in ATCC 17616 without the upregulation of the bce-I and bce-II EPS gene clusters, despite their pivotal role in EPS biosynthesis. Of approximately 20 differentially expressed putative virulence factors, 16 exhibited upregulation including flagella, ornibactin, oxidative stress proteins and phospholipases. MYEM-grown B. multivorans also exhibited enhanced motility, biofilm formation and epithelial cell invasion. In contrast to these potential virulence enhancements, MYEM-grown B. multivorans C1576 showed attenuated virulence in the Galleria mellonella infection model. All of the observed phenotypic responses occurred independently of EPS production, highlighting the profound impact that mannitol-based growth has on the physiology and virulence of B. multivorans.

Current dilemmas in antimicrobial therapy in cystic fibrosis

The majority of cystic fibrosis (CF)-related morbidity and mortality is caused by pulmonary damage due to recurrent and chronic infections. Considerable improvements in the survival of individuals with CF have been achieved in recent decades, some of which may be due to better management of common pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa. While the search continues for the optimal approach for prophylaxis, eradication and maintenance treatment of infections, there are several unanswered questions, posing dilemmas related to various therapeutic choices. Microbes pose additional challenges by adapting to CF lungs and developing treatment resistance. Several new, highly antimicrobial-resistant pathogens have emerged. Their pathogenic role in the progression of CF lung disease is not yet clear and effective treatment approaches have not been defined. There is an urgent need for well-designed comparative clinical trials of new antibiotic strategies.

Use of the gyrB gene to discriminate among species of the Burkholderia cepacia complex

Bacteria of the Burkholderia cepacia complex (Bcc) are opportunistic pathogens that can cause serious infections in lungs of cystic fibrosis patients. The Bcc comprises at least nine species that have been discriminated by a polyphasic taxonomic approach. In this study, we focused on the gyrB gene, universally distributed among bacteria, as a new target gene to discriminate among the Bcc species. New PCR primers were designed to amplify a gyrB DNA fragment of about 1900 bp from 76 strains representative of all Bcc species. Nucleotide sequences of PCR products were determined and showed more than 400 polymorphic sites with high sequence similarity values from most isolates of the same species. Phylogenetic tree analysis revealed that most of the 76 gyrB sequences grouped, forming clusters, each corresponding to a given Bcc species.

Multidrug-resistant organisms in cystic fibrosis: management and infection-control issues

Chronic infection and inflammation are the hallmarks of cystic fibrosis lung disease. As cystic fibrosis patients are living longer owing to more intense treatment, multidrug-resistant organisms are being isolated increasingly from patients' respiratory tracts. While the adverse effects of Pseudomonas aeruginosa and Burkholderia cepacia complex are well described, less is known about the clinical significance of other emerging multidrug-resistant organisms, such as methicillin-resistant Staphylococcus aureus and Stenotrophomonas maltophilia. Owing to multiple mechanisms of antimicrobial resistance, these organisms are difficult to treat and often require combination antibiotic therapy. Until more is known about their pathogenicity and effect on clinical outcomes, physicians should be aware of the potential transmissibility of these organisms and implement adequate infection control strategies.

Burkholderia cepacia complex species: health hazards and biotechnological potential

The Burkholderia cepacia complex is a group of nine closely related bacterial species that have useful properties in the natural environment as plant pest antagonists, plant growth promoters and degradative agents of toxic substances. Because these species are human opportunistic pathogens, especially in cystic fibrosis patients, biotechnological applications that involve environmental releases have been severely restricted. Recent progress in understanding the taxonomy, epidemiology and ecology of the B. cepacia complex species has unravelled considerable variability in their pathogenicity and ecological properties, which has set the basis for a reassessment of the risk posed by individual species to human health.

Nebulized antibiotic therapy: the evidence

The main indications for nebulized antibiotic use are as maintenance therapy for patients with chronic Pseudomonas aeruginosa infection and in treatment protocols aimed at eradicating early P. aeruginosa infection. Daily nebulized antibiotic therapy has been used extensively in Europe for the last 25 years and recently in North America following the introduction of tobramycin solution for inhalation (TSI). The antibiotic is delivered directly to the site of infection, maximizing its efficacy and reducing its potential for toxicity. The efficacy of nebulized antibiotic therapy has been confirmed by meta-analyses of early studies which usually involved only small numbers of patients, and recently by large scale randomized control trials. These studies have shown that regular aerosolized antibiotic treatment results in improved respiratory function, less hospital admissions and respiratory exacerbations, and a significant reduction in the load of P. aeruginosa respiratory tract infection. Concerns about increasing bacterial resistance do not yet seem to have had any clinical impact. Successful eradication of early P. aeruginosa infection has been reported with nebulized colistin (in combination with oral ciprofloxacin), tobramycin and TSI. No advantage has been shown in studies comparing nebulized and intravenous antibiotics versus intravenous antibiotics alone in the treatment of acute respiratory exacerbations. Inhalation of antibiotics may provoke bronchospasm and patients should be assessed before and after treatment prior to continuing long-term therapy at home.