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 ± 3.3 years) 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 3 months 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 ≥. 30 ng/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.