Is the Improvement of CF Patients, Hospitalized for Pulmonary Exacerbation, Correlated to a Decrease in Bacterial Load?

Background: Cystic Fibrosis (CF) patients are vulnerable to airway colonization with Pseudomonas aeruginosa. In case eradication fails after antibiotic treatment, patients become chronically colonized with P. aeruginosa, with recurrent pulmonary exacerbation, for which patients typically are hospitalized for 2 weeks and receive intravenous antibiotic treatment. Normally, improvement of the patients ’ health is established. Aim: Determination of the correspondence between patient improvement and changes of the P. aeruginosa and total bacterial load in the sputum. Methods: Eighteen CF patients with exacerbation were included for a total of 27 hospitalization episodes. At day 1, 8 and 15, inflammation and lung function parameters were determined, together with the P. aeruginosa load in the sputum using culture, quantitative PCR (qPCR) and propidium monoazide qPCR. Results: Patients improved during hospitalization (decrease in levels of C-reactive protein, white blood cell counts and erythrocyte sedimentation rate, increase of FEV1), reaching normal values already after one week. Also the P. aeruginosa load and the total bacterial load decreased during the first week of antibiotic treatment (p,0.05), except for patients with a low lung function (FEV1#39.4%), for whom no significant decrease of P. aeruginosa was established. Comparison of culture-based and propidium monoazide qPCR-based quantification of P. aeruginosa showed that at the end of the treatment o