Bacterial Surface Detachment during Nebulization with Contaminated Reusable Home Nebulizers.

Patients with chronic respiratory diseases use home nebulizers that are often contaminated with pathogenic microbes to deliver aerosolized medications. The conditions under which these microbes leave the surface as bioaerosols during nebulization are not well characterized. The objectives of this study were to (i) determine whether different pathogens detach and disperse from the nebulizer surface during aerosolization and (ii) measure the effects of relative humidity and drying times on bacterial surface detachment and aerosolization. Bacteria were cultured from bioaerosols after Pari LC Plus albuterol nebulization using two different sources, as follows: (i) previously used nebulizers donated by anonymous patients with cystic fibrosis (CF) and (ii) nebulizers inoculated with bacteria isolated from the lungs of CF patients. Fractionated bioaerosols were collected with a Next-Generation Impactor. For a subset of bacteria, surface adherence during rewetting was measured with fluorescence microscopy. Bacteria dispersed from the surface of used CF patient nebulizers during albuterol nebulization. Eighty percent (16/20) of clinical isolates inoculated on the nebulizer in the laboratory formed bioaerosols. Detachment from the plastic surface into the chamber solution predicted bioaerosol production. Increased relative humidity and decreased drying times after inoculation favored bacterial dispersion on aerosols during nebulized therapy. Pathogenic bacteria contaminating nebulizer surfaces detached from the surface as bioaerosols during nebulized therapies, especially under environmental conditions when contaminated nebulizers were dried or stored at high relative humidity. This finding emphasizes the need for appropriate nebulizer cleaning, disinfection, and complete drying during storage and informs environmental conditions that favor bacterial surface detachment during nebulization.