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. Objecrives 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. aeruginosa. Simple oral and written cleaning instructions should be offered.