Abstract Number: 537 Working Group: Health Related Aerosols
Abstract Bioaerosols have a significant impact on health, as they are a major mode of transmission of infectious respiratory diseases such as influenza. Additionally, bioaerosols exacerbate respiratory inflammatory diseases such as chronic pulmonary obstructive disease (COPD) and hypersensitivity pneumonitis (HP). In spite of this, the factors that influence the creation and transport of bioaerosols in both environmental and human-engineered settings are not well understood. Some organisms may be more readily aerosolised than others, known as preferential aerosolisation. This was first demonstrated for nontuberculous mycobacteria (NTM) in an article published in 1983 by Parker et al. More recently, ‘selective’ aerosolisation was observed by Moletta et al, where the biodiversity of bioaerosols and their liquid sources was compared. The authors found that there were higher proportions of some organisms in the bioaerosols than in the liquid source. However, further research into this phenomenon has not been undertaken. Importantly, the dynamics between bacteria during aerosolisation processes must be better understood.
We hypothesised that organisms ‘compete’ during aerosolisation processes, and that as a result, some organisms are preferentially aerosolised. A small aerosol chamber was designed for the study of the aerosolisation of several microorganisms simultaneously. Mycobacterium avium, Pseudomonas aeruginosa and Staphylococcus aureus were aerosolised both simultaneously and separately. A bubbling nebuliser was used to produce bioaerosols, to mimic natural aerosol production and an SKC biosampler was used to collect air samples from the chamber. The nebulising liquid and the air samples were analysed by culture, qPCR, and fluorescence microscopy. We found that P.aeruginosa was more easily aerosolised by bubbling when a mixed suspension was nebulised. We also found that when M.avium was aerosolised with S.aureus and P.aeruginosa, it significantly diminished the aerosolisation of P.aeruginosa, but not of S.aureus. We conclude that the presence of M.avium prevents other bacteria from being efficiently aerosolised.