Microbial contamination of nebulizers in the home treatment of cystic fibrosis

Background: Home nebulizers are in widespread use in cystic fibrosis (CF) and other chronic pulmonary diseases. Bacterial contamination may be a source of respiratory tract colonization. Objectives: To investigate microbial contamination of home nebulizers in CF patients, compare with sputum cultures and relate to cleaning practices. Methods: A total of 29 home nebulizers of CF patients were cultured. Families were interviewed regarding cleaning routines and patients had sputum cultures for bacteria and fungi. Results: In total, 19/29 (65%) nebulizers were contaminated: 18 reservoir cups, 14 mouthpieces and five filters. Pseudomonas spp. were isolated from 10 nebulizers (35%) and all 10 had Pseudomonas aeruginosa airway infection although without genetic typing we could not be sure this was the same bacteria as that from their nebulizer unit. An additional 7/29 had Pseudomonas aeruginosa airway infection without a contaminated nebulizer (P = 0.001). No nebulizers were contaminated with Aspergillus. Only 4/19 contaminated nebulizers (22%) had been cleaned after every use, compared with seven of the 10 (70%) uncontaminated nebulizers (P = 0.017). Only 7/19 patients with contaminated nebulizers (37%) and 5/10 with clean nebulizers (50%) recalled receiving cleaning instructions (not significant). Conclusions: Home nebulizers are frequently contaminated, particularly when cleaning instructions are inadequate, and may be a source of airway infection or reinfection especially following contamination from a patient chronically colonized with P. eruginosa. Simple oral and written cleaning instructions should be offered.