Early Pseudomonas aeruginosa colonisation in cystic fibrosis patients

Abstract

Authors' reply Sir—Giovanni Taccetti and colleagues' treatment strategy seems to be as successful as our strategy attention. Taken together, the two studies suggest that the decisive moment when antibiotic treatment is started–ie, early after bacterial lung colonisation–is more important than the choice of the drug. However, this is valid only if the infecting pathogen is drug sensitive. If CF patients become infected with sensitive environmental P aeruginosa strains, several drugs can be used to eradicate early lung infection. When the infecting strain is drug resistant, clinicians need to select the antibiotic according to the sensitivity pattern. Unfortunately, Taccetti and colleagues do not comment on the sensitivity of P aeruginosa in patients in whom eradication failed. On the basis of the small number of patients in their and our own study, we agree that multicentre studies are needed to find the optimum drug treatment. Multicentre studies may also strengthen Taccetti and colleagues' second issue about a shorter treatment period than the 12 months in our study. Although one 3-week treatment course may eradicate P aeruginosa in CF patients, assessment of treatment efficacy by throat cultures and serology is difficult in such a short time when antibiotic treatment is given at home.1Döring G Conway SP Heijerman HGM et al.Consensus CommitteeAntibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis: a European consensus.Eur Respir J. 2000; 16: 749-767Crossref PubMed Scopus (503) Google Scholar For most CF patients worldwide, visits to CF centres every 3 weeks are not feasible, and longer treatment periods have to be considered. Given the sharp decline in the number of CF patients with positive P aeruginosa throat cultures after 3 months in our and Taccetti and colleagues' study, such a period may be considered for most but not all CF patients. The lack of information on how long Taccetti and colleagues' CF patients remained free of P aeruginosa after treatment makes comparison of their data with ours difficult. In our study, 14 of 15 patients remained free of P aeruginosa for at least 12 months after treatment was stopped. Future studies should investigate this time for different regimens and, in addition, define how eradication is assessed. We assume that Taccetti and colleagues base eradication on the absence of P aeruginosa throat cultures and negative titres of antibodies to P aeruginosa, as defined in our own study. Antibodies to P aeruginosa should be assessed at least quarterly when shorter durations of antibiotic treatment are considered.1Döring G Conway SP Heijerman HGM et al.Consensus CommitteeAntibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis: a European consensus.Eur Respir J. 2000; 16: 749-767Crossref PubMed Scopus (503) Google Scholar Furthermore, in future studies, sequential P aeruginosa isolates from individuals need to be genotyped to distinguish between eradication and suppression of the pathogen. Early Pseudomonas aeruginosa colonisation in cystic fibrosis patientsF Ratjen and colleagues (Sept 22, p 983)1 report their experience with Pseudomonas aeruginosa colonisation in patients with cystic fibrosis (CF). Full-Text PDF