Association between sputum culture results and pulmonary changes in children with cystic fibrosis

Despite the significant improvement in the prognosis of cystic fibrosis (CF), it is still regarded as the most common life-shortening genetic disease in Caucasian populations. This disease is the most important cause of chronic lung disease and exocrine pancreatic insufficiency in infancy and childhood. The aim of our study was to assess the potential association between bacterial colonization detected by sputum cultures and pulmonary structural and functional changes in Iranian children with CF.

In this cross-sectional study, 76 CF children ≥6 years old registered in the CF Foundation of Chil- dren’s Medical Center Hospital, Tehran, Iran, who underwent high resolution CT scan (HRCT), pulmonary function test, and sputum cultures within a month of each other during the study period were included. For each patient, demographic charac- teristics (age and sex), results of sputum cultures, forced expiratory volume in 1st second (FEV1), and chest HRCT findings based on the Bhalla scoring system were recorded in a check list.

Sixty seven percent of the patients had positive sputum cultures, with the most commonly isolated microorganism being Pseudomonas aeruginosa (mucoid strain). Based on categorization of Bhalla scores, none of the patients had severe pulmonary involvement. FEV1 was mainly >70%. There was a statistically significant correlation between colonization with mucoid P. aeruginosa and lower Bhalla scores in children aged 14-16 years (P=0.001). Colonization with mucoid P. aerugi- nosa was also significantly associated with patient's age (P=0.020) and FEV-1 (P=0.001).

Severity of lung involvement in CF children is clearly dependent to mucoid P. aeruginosa colonization in airways and this notorious bacterium is the most prevalent one in Iranian CF children. Prompt identification and eradication by proper nebulized and systemic antibiotics can have valueless effects on patients’ quality of life and prevent lifelong de- structive complications such as bronchiectasis. Timely lung CT scan wisely advised by expert CF treatment team can metic- ulously detect injuries and it seems to act more efficacious than -still helpful- clinical scores and pulmonary function tests.