Antibiotic treatments for long-term Burkholderia cepacia infections in people with cystic fibrosis

Review question

We reviewed the evidence for long-term antibiotic treatments for people with cystic fibrosis who are infected with Burkholderia cepacia complex (bacteria composed of at least 20 different species).

Background

People with cystic fibrosis often suffer from repeated chest infections and eventually their lungs become permanently infected by bacteria, such as a family of bacteria called Burkholderia cepacia complex which can cause problems because many antibiotics do not work against them and they can cause a quicker deterioration in lung disease. We wanted to discover whether using long-term antibiotic treatment was beneficial for people with cystic fibrosis and Burkholderia cepacia complex infection.

Search date

The evidence is current to: 29 May 2019.

Study characteristics

This review included one study of 100 people aged between 6 and 57 years old. The study compared an inhaled antibiotic called aztreonam to placebo (a substance which contains no medication) and people were selected for one treatment or the other randomly (by chance). The study lasted 52 weeks.

Key results

The only study included in this review found inhaled aztreonam had no beneficial effect on lung function or rates of chest infections in people with cystic fibrosis and Burkholderia cepacia complex infection. There was no difference between groups in relation to the average time to the next exacerbation or the number of people hospitalised for an exacerbation. Overall adverse events were similar between groups and with regards to other outcomes assessed, there was no difference between treatment groups for mortality, quality of life or sputum density. More research is needed to establish if other inhaled antibiotics may be useful.

Quality of the evidence

Overall quality of evidence was considered to be moderate across all outcomes, which means further research is likely to have an important impact on results.

Authors' conclusions: 

We found insufficient evidence from the literature to determine an effective strategy for antibiotic therapy for treating chronic BCC infection.

Read the full abstract...
Background: 

Cystic fibrosis (CF) a life-limiting inherited disease affecting a number of organs, but classically associated with chronic lung infection and progressive loss of lung function. Chronic infection by Burkholderia cepacia complex (BCC) is associated with increased morbidity and mortality and therefore represents a significant challenge to clinicians treating people with CF. This review examines the current evidence for long-term antibiotic therapy in people with CF and chronic BCC infection.

Objectives: 

The objective of this review is to assess the effects of long-term oral and inhaled antibiotic therapy targeted against chronic BCC lung infections in people with CF. The primary objective is to assess the efficacy of treatments in terms of improvements in lung function and reductions in exacerbation rate. Secondary objectives include quantifying adverse events, mortality and changes in quality of life associated with treatment.

Search strategy: 

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched online trial registries and the reference lists of relevant articles and reviews.

Date of last search: 29 May 2019.

Selection criteria: 

Randomised controlled trials (RCTs) of long-term antibiotic therapy in people with CF and chronic BCC infection.

Data collection and analysis: 

Two authors independently extracted data, assessed risk of bias and assessed the quality of the evidence using GRADE.

Main results: 

We included one RCT (100 participants) which lasted 52 weeks comparing continuous inhaled aztreonam lysine (AZLI) and placebo in a double-blind RCT for 24 weeks, followed by a 24-week open-label extension and a four-week follow-up period. The average participant age was 26.3 years, 61% were male and average lung function was 56.5% predicted.

Treatment with AZLI for 24 weeks was not associated with improvement in forced expiratory volume in one second (FEV1), mean difference 0.91% (95% confidence interval (CI) -3.15 to 4.97) (moderate-quality evidence). The median time to the next exacerbation was 75 days in the AZLI group compared to 51 days in the placebo group, but the difference was not significant (P = 0.27) (moderate-quality evidence). Similarly, the number of participants hospitalised for respiratory exacerbations showed no difference between groups, risk ratio (RR) 0.88 (95% CI 0.53 to 1.45) (moderate-quality evidence). Overall adverse events were similar between groups, RR 1.08 (95% CI 0.98 to 1.19) (moderate-quality evidence). There were no significant differences between treatment groups in relation to mortality (moderate-quality evidence), quality of life or sputum density.

In relation to methodological quality, the overall risk of bias in the study was assessed to be unclear to low risk.

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