Clinical features associated with Pseudomonas aeruginosa colonization in children under 2 years of age: a retrospective study of Cystic Fibrosis Registry

Background. Respiratory colonization with Pseudomonas aeruginosa is associated with increased morbidity and mortality in cystic fibrosis (CF) patients. This study aims to assess the clinical characteristics and associated factors of CF infants under two years of age with P. aeruginosa colonization in Türkiye. Method. Of the 1637 patients registered in the Cystic Fibrosis Registry of Türkiye in 2019, 284 patients under two years of age were included in this retrospective cross-sectional study. Patients were classified into two groups: those with P. aeruginosa colonization (Group 1) and those without (Group 2). Cystic fibrosis transmembrane conductance regulator (CFTR) gene functions were categorized according to CFTR mutation functional class. Results. Twenty-three patients (8.1%) were categorized as Group 1 and 262 participants (91.9%) were classified as Group 2. Infants with P. aeruginosa colonization (Group 1) were more likely to have minimal CFTR function compared with those without colonization (87% vs. 39.8%, p = 0.017). In addition, both Staphylococcus aureus colonization (47.8% vs. 7.3%, p < 0.001) and methicillin-resistant S. aureus positivity (17.4% vs. 6.1%, p = 0.042) were observed more commonly in Group 1. There were no statistical differences between the groups in terms of age at diagnosis, gender, mean z-scores of weight and height, newborn screening test positivity, sweat chloride test results, and pancreatic insufficiency (p > 0.05). Univariate logistic regression analysis did not identify significant associated factors for P. aeruginosa colonization. Conclusions. Our findings suggest that minimal CFTR function and S. aureus colonization are associated with P. aeruginosa colonization in CF patients under two years of age. Further studies are needed to investigate associated factors for early P. aeruginosa colonization, eradication treatment effectiveness, and longitudinal outcomes of in CF patients under two years of age.