Streptococcus pneumoniae oropharyngeal colonization in children and adolescents with cystic fibrosis

Background This study was designed to evaluate Streptococcus pneumoniae ( S . pneumoniae ) carriage rates in patients with cystic fibrosis (CF). Methods An oropharyngeal swab was obtained from 212 CF children and adolescents enrolled during routine clinical visits. DNA from swabs was analyzed by real-time polymerase chain reaction. Results A total of 42 (19.8%) CF patients (mean age±standard deviation [SD], 12.0±3.3years) were colonized by S. pneumoniae . Carriage was more common in younger patients and tended to decline with age. Administration of systemic and/or inhaled antibiotics in the last 3months significantly correlated with a reduced carrier state [odds ratio (OR) 0.23, 95% confidence interval (CI) 0.07–0.69, and OR 0.26, 95% CI 0.08–0.77, respectively]. Vitamin D serum levels ≥30ng/mL were less common in carriers than that in non-carriers (OR 0.35; 95% CI 0.08–1.49). In both the vaccinated and unvaccinated subjects, serotypes 19F, 5, 4, and 9V were the most commonly carried serotypes. Conclusions S. pneumoniae carrier state of school-age children and adolescents with CF is more prevalent than previously thought, and pneumococcal conjugate vaccination administered in the first year of life does not reduce the risk of re-colonization in later childhood and adolescence.