Inhaled colistin following lung transplantation in colonised cystic fibrosis patients

Inhaled colistin following lung transplantation in colonised cystic fibrosis patientsTo the Editor:Respiratory tract infections due to viral, bacterial or even fungal pathogens are common after lung transplantation [1].Previous studies demonstrated increased hospitalisation rates and a greater risk of chronic lung allograft dysfunction in colonised patients with cystic fibrosis (CF) [2].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 [5].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).CF patients who underwent lung transplantation between January 1, 2005 and May 1, 2011 were included and follow-up continued until June 6, 2011.Perioperative antibiotics were continued for 2 weeks after lung transplantation, consisting of combination therapy based on previous microbiological findings.A routine surveillance programme at 1, 3, 6, 9 and 12 months after transplantation included pulmonary function testing, blood gas analysis and bronchoscopy with bronchoalveolar lavage (BAL).Quantitative microbial status was assessed by microbial investigation of BAL, as previously described [6].According to the presence of bacteria in the first BAL following lung transplantation, patients were categorised as 1) patients with colonisation or 2) patients without colonisation.Within these two groups, patients were subclassified depending on their treatment with inhaled colistin, as there was no standardised protocol for beginning colistin inhalation.The inhalation of colistin (1 million IU twice daily) was started immediately after transplantation (PARI BOY; PARI GmbH, Starnberg, Germany) and only patients with at least 3 months continuous colistin use after transplantation were allocated to the colistin-treated groups.All potential pathogens were included in analysis and the presence of o1 bacterial colony after 48 h of culturing was considered significant.Colonisation was defined as repeated detection of the same pathogen in two consecutive BALs.Timing of eradication was defined as the first of three consecutive negative cultures.Statistical analysis was performed using SPSS Version 18 (SPSS Inc., Chicago, IL, USA).All reported pvalues are two-sided and p-values ,0.05 were considered statistically significant.Chi-squared test and t-test were performed.