Inhaled antibiotics in Cystic Fibrosis (CF) and non-CF bronchiectasis

Bronchiectasis is a pathological diagnosis describing dilatation of the airways and is characterized by chronic lung sepsis. Bronchiectasis has multiple etiologies, but is usually considered in terms of whether it is due to the genetic disorder cystic fibrosis (CF) or secondary to other causes (non-CF bronchiectasis, NCFB). Inhaled antibiotics are used in bronchiectasis to suppress bacterial pathogens and reduce long-term lung function decline. The majority of the literature on inhaled antibiotics comes from studies on CF where the dominant bacterial pathogen in the airway is usually Pseudomonas aeruginosa. Thus, most aerosolized antibiotic regimens target this bacterium, but the emergence of molecular diagnostic methods has questioned this approach and more tailored strategies may need to be considered in CF based on the community composition of the lung microbiome. Similarly, the lung microbiome in NCFB has been found to be a complex polymicrobial one and the current practice of employing the same inhaled antibiotic regimes as are used in CF may no longer be appropriate in many patients. In this article, the use of inhaled antibiotics in CF and NCFB is considered in the light of improved understanding of the lung microbiome and why more tailored therapy may be needed based on molecular identification of the microbial pathogens present. The evidence for the use of currently available inhaled antibiotics and advances in inhaled drug packaging and delivery devices are discussed. Finally, the urgent need for prospective randomized clinical trials in CF and NCFB is highlighted and areas for future research identified.