Application of a Simple Method to Study Single-Particle Bioaerosols Including Preferential Aerosolization

Bacteria, viruses, fungus, and other biological components (toxins, membranes, spores) can spread in the air through various aerosolization processes (breathing, bubbling, explosion, evaporation) and travel until they reach a surface or a host. Nosocomial diseases are an example of illnesses caused by a human contact with such pathogen vectors in hospital settings. Very little is known about the aerosolization processes of viruses and bacteria and their potential to infect people after their passage in the airborne state and about the microbial burden carried by individual aerosol particles. Here we propose a novel approach to study the aerosolization mechanisms of bacteria in single particles using fluorescence spectroscopy and a homemade system allowing the control of the aerosolization and the impaction of bacteria on a black filter. We validated the concept using P. fluorescence and E. coli. The results show that independently of the amount of P. fluorescens and E. coli aerosolized the average distribution of cells impacted on a black filter is described by a Poisson fit with λ ∼ 0.6 ± 0.2. This means that using this aerosolization process, an aerosol will present no bacterium, but when it does, the number of bacteria per particle in the distributions will more probably be one. We also observed that the aerosolization processes of these two bacterial species allow P. fluorescens to be preferentially aerosolized against E. coli. These results demonstrate that fluorescence spectroscopy is a powerful tool to study bioaerosols in single particles. This technique can be used to study several phenomena like preferential aerosolization.Copyright 2015 American Association for Aerosol Research