Respiratory tract infections due to viral, bacterial or even fungal pathogens are common after lung transplantation . Previous studies demonstrated increased hospitalisation rates and a greater risk of chronic lung allograft dysfunction in colonised patients with cystic fibrosis (CF) . Positive effects of inhaled antibiotics have been demonstrated for pneumonia in non-transplant patients with improvements of lung function, hospitalisation rates and need for i.v. antibiotics [3, 4]. Inhaled colistin is known to provide high drug concentrations in sputum while low systemic concentrations occur and treatment is well tolerated . Here, the impact of inhaled colistin, both in reducing bacterial load in previously colonised patients and as a preventive therapy in non-colonised CF patients, after lung transplantation, was studied in a retrospective single-centre study (Hanover Medical School, Hanover, Germany).