Buccal Adherence of Pseudomonas aeruginosa in Patients with Cystic Fibrosis under Long-Term Therapy with Azithromycin

Background: The oropharyngeal barrier is an innate host defence mechanism to prevent bacterial lung infection. A compromised barrier function is observed in patients with cystic fibrosis (CF) who are chronically infected with Pseudomonas aeruginosa. Macrolides are assumed to modify host defence. We investigated the oropharyngeal barrier function in CF patients treated with azithromycin (AZM). Patients and Methods: In a prospective study, eleven chronically infected children with CF were treated with long-term low-dose AZM. The oropharyngeal barrier function was assessed by adherence of P. aeruginosa (strain PACF 12-1) to buccal epithelial cells of the patients before and after therapy. Results: The mean (standard deviation, SD) buccal adherence before therapy was markedly high with 8.0 (4.8) bacteria/cell. Following therapy with AZM adherence decreased in all patients by 70% or 5.6 to 2.4 (1.1) bacteria/cell (p = 0.007), representing close to normal levels (1.2 ± 0.6). Conclusion: Long-term low-dose AZM therapy may improve the compromised oropharyngeal barrier function in patients with CF, opening new perspectives for early treatment of P. aeruginosa infection in CF. Received: February 28, 2000 · Revision accepted: August 16, 2000