Antibiotic adjuvant therapy for pulmonary infection in cystic fibrosis

Abstract

Background: Cystic fibrosis is a multi-system disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. This leads to lung destruction and eventually death through respiratory failure. There are no antibiotics in development that exert a new mode of action and many of the current antibiotics are ineffective in eradicating the bacteria once chronic infection is established. Antibiotic adjuvants - therapies that act by rendering the organism more susceptible to attack by antibiotics or the host immune system, by rendering it less virulent or killing it by other means, are urgently needed.

Objectives: To determine if antibiotic adjuvants improve clinical and microbiological outcome of pulmonary infection in people with cystic fibrosis.

Search strategy: We searched the Cystic Fibrosis Trials Register which is compiled from database searches, hand searches of appropriate journals and conference proceedings.Date of most recent search: 26 August 2010.We also searched MEDLINE (all years) on 21 July 2010.

Selection criteria: Randomised controlled trials and quasi-randomised controlled trials of a therapy exerting an antibiotic adjuvant mechanism of action compared to placebo or no therapy for people with cystic fibrosis.

Data collection and analysis: The authors independently assessed and extracted data from identified studies.

Main results: We identified eighteen studies of which three are included that examined antibiotic adjuvant therapies, five studies are ongoing. The included studies involve the assessment of β-carotene, garlic and zinc supplementation. No therapy demonstrated a significant effect upon pulmonary function, pulmonary exacerbations or quality of life. The study of zinc supplementation reports a reduction in the requirement of oral antibiotics but not of intravenous antibiotics, an effect that is difficult to understand.

Authors' conclusions: We could not identify an antibiotic adjuvant therapy that could be recommended for the treatment of lung infection in those with cystic fibrosis. The emergence of increasingly resistant bacteria makes the reliance on antibiotics alone challenging for cystic fibrosis teams. There is a need to explore alternative strategies, such as the use of adjuvant therapies. Further research is required to provide future therapeutic options.