Inhaled antibiotics and non-cystic fibrosis bronchiectasis: Trying to solve the puzzle

Bronchiectasis is a chronic airway disease with recurrent exacerbations and hospitalisations. No inhaled antibiotic has shown consistently beneficial effects in trials. This review analyses the evidence on inhaled antibiotics in non-cystic fibrosis bronchiectasis (NCFB), identifies patient traits for their use, and highlights research gaps. A PubMed search for "Inhaled antibiotics AND bronchiectasis" identified five inhaled antibiotics studied in randomised controlled trials (RCTs): aztreonam, tobramycin, gentamycin, ciprofloxacin, and colistin. Inhaled antibiotics reduced exacerbation frequency, sputum bacterial density, and increased bacterial eradication but did not improve lung function. They also increased antimicrobial resistance, with aztreonam and aminoglycosides having higher discontinuation rates due to side effects. Increased sputum bacterial density (>107 colony forming units/g), increased exacerbation frequency (≥4) at baseline, and increased sputum volume and/or purulence at baseline are some of identifiable traits associated with benefit from inhaled antibiotics. Inhaled antibiotics may aid in eradicating Pseudomonas aeruginosa after first isolation in NCFB, but their role in acute exacerbations requires further research. There are no direct RCTs comparing different delivery systems, antibiotics, and regimens.