ACQUISITION OF PSEUDOMONAS-AERUGINOSA IN CHILDREN WITH CYSTIC-FIBROSIS

Objective. This study was pursued as an extension of a randomized clin ical investigation of neonatal screening for cystic fibrosis (CF). The project included assessment of respiratory secretion cultures for pat hogens associated with CF. The objective was to determine whether pati ents diagnosed through neonatal screening and treated in early infancy were more likely to become colonized with Pseudomonas aeruginosa comp ared with those identified by standard diagnostic methods. Methodology . The design involved prospective cultures of respiratory secretions o btained generally by oropharyngeal swabs at least every 6 months and m ore often if clinically indicated. Patients were managed with a standa rdized evaluation and treatment protocol at the two Wisconsin certifie d CF centers; however, there were community and environmental variatio ns associated with the follow-up period as described below. Results. O verall, there were no differences in acquisition of respiratory pathog ens between the screened and the control (standard diagnosis) groups. Evaluation of the data between and within the two centers, however, re vealed significant differences with earlier acquisition of P aeruginos a in the center with the following distinguishing characteristics: urb an location; following patients with the standard US approach in which newly diagnosed, young children were interspersed with older CF patie nts; and where there were more opportunities for social interactions w ith other CF patients. The differences were confined to the screened g roup followed in the urban center in which the median pseudomonas-free survival period was 52 weeks contrasted with 289 weeks in the other c enter. In addition, assessment of data for the entire CF populations f ollowed at the two centers revealed that the urban center showed a sig nificantly higher prevalence of P aeruginosa colonization in patients between the ages of 3 and 9 years. Conclusions. These results present questions and generate hypotheses on risk factors for acquisition of P aeruginosa in CF and suggest that clinic exposures and/or social inte ractions may predispose such patients to pseudomonas infections.