Risk factors for initial acquisition of Pseudomonas aeruginosa in children with cystic fibrosis identified by newborn screening

The objective of this study was to identify risk factors for initial detection of Pseudomonas aeruginosa (P. aeruginosa) in children with cystic fibrosis (CF) identified by newborn screening. Life history data on 180 patients, collected prospectively in a follow-up study of infants and children diagnosed with CF, were examined for factors associated with the initial detection of P. aeruginosa ascertained by oropharyngeal cultures. Univariate and multivariate Cox proportional hazards regression analyses were used to assess the effect of baseline and time-varying covariates on age at first positive culture for P. aeruginosa. Seventy-nine patients (44%) had at least one culture positive for P. aeruginosa during the study. The median age of detection was 8.1 years (95% CI, 7.0, 10.0). Median length of follow-up was 4.1 years, ranging from 0.2-15.5 years. Multivariate Cox regression analysis identified female gender (RR, 1.85; 95% CI, 1.14, 3.01), the DeltaF508 homozygous genotype (RR, 2.23; 95% CI, 1.30, 3.80), and S. aureus isolations (RR, 1.30; 95% CI, 1.11, 1.52) to be independently associated with acquisition of P. aeruginosa. Other marginally independent associations were found with days hospitalized and increased height. We conclude that female gender, homozygous DeltaF508 mutation, and S. aureus isolations are important risk factors for early P. aeruginosa detection in children with CF identified through newborn screening.