Microbial contamination of home nebulizers in children with cystic fibrosis and clinical implication on the number of pulmonary exacerbations.

Background: Early detection of pulmonary contamination in children with cystic fibrosis (CF) is essential since these children are vulnerable to Pseudomonas aeruginosa (P. aeruginosa) colonization. In Iran, home nebulization of antibiotics is a widespread practice in treatment for patients with CF and, to the best our knowledge, no bacteriological surveys have been conducted till date in this regard.

Method: This observational, cross sectional study was conducted on 61 children with CF at Mofid Children's Hospital, Tehran, from September 2017 to march 2018. The swab sampling was performed from 61 home nebulizers used by children diagnosed with CF. Contemporaneous sputum sample or deep nasopharyngeal swab was taken from each patient for bacterial and fungal testing. Medical records of the patients were reviewed and the number of exacerbations were recorded over the last 12 months prior to the study enrollment.

Results: The results of study showed that, 43 (70.5%) nebulizers were contaminated; 31 (50.8%) mouthpieces, 21 (34.4%) reservoirs, and 11 (18%) connecting tubes. The most common organism to be isolated was P. aeruginosa and was recovered from 19 (31%) nebulizers, 16 of them belonged to patients chronically colonized with P. aeruginosa. The remaining three had at least one positive sputum culture for P. aeruginosa in the past 1 year before the study. There was a significant increase in the number of CF exacerbations with an average number of exacerbation being 1.5 ± 1(SD) over last 12 months in children who had pathogenic organisms recovered from their home nebulizers compared with 0.4 ± 0.7(SD) exacerbations per year in whom non-pathogenic organisms were isolated from their nebulizers (P < 0.001).

Conclusion: The majority of domiciliary nebulizers used by children with CF were contaminated with microorganisms indicating that the nebulizers may serve as potential reservoirs of pathogens for the patients' lung. Perpetuating colonization is a possible concern in the ones recently colonized with P. aeruginosa and, therefore, decontamination of nebulizer requires more attention to prevent ongoing infection. The negative impact of contamination of nebulizer on CF exacerbation requires serious attention and further investigations.