AbstractIn addition to bacteria and inflammatory cells, the sputum of patients with bronchiectasis contains mediators that damage the airway epithelium and promote inflammatory change. The deleterious effects of these mediators, such as neutrophil elastase, reduce host defences and consequently perpetuate the propensity to recurrent infection. This ‘vicious cycle’ of infection and inflammation in bronchiectasis suggests that long-term antibiotic therapy might be beneficial in these patients by reducing microbial load and, in doing so, inhibit inflammation in the lung allowing tissue repair to occur. Short courses of antibiotics achieve clinical improvements and also have been shown to reduce the levels of harmful mediators in the sputum. Th...