Concentrating Viable Airborne Pathogens Using a Multi-Nozzle Virtual Impactor Paired With a Compact Water-Based Condensation Air Sampler
William B. Vass, SRIPRIYA NANNU SHANKAR, John Lednicky, Morteza Alipanah, Braden Stump, Patricia Keady, Z. Hugh Fan, Chang-Yu Wu, University of Florida
Abstract Number: 623
Working Group: Bioaerosols
Abstract
People are constantly exposed to bioaerosols through the ambient air that they breathe. While there are several methods to collect and detect pathogens from the air, the infectivity of those agents must be assessed to fully evaluate health risks from exposure to airborne pathogens. Air samplers which operate by growing particles through water vapor condensation and subsequently collecting them into a liquid medium have proven effective at conserving the viability of microorganisms. We present a study that assessed the performance improvement of one such sampler, BioSpot-GEMTM, gained by augmenting it with an upstream multi-nozzle virtual impactor (VI) designed to concentrate particles in aerosols. Two test organisms viz., Escherichia coli and human coronavirus OC43 were aerosolized using a Sparging Liquid Aerosol Generator and a 3-jet Bioaerosol Nebulizing Generator respectively, in custom-built laboratory air chambers. Post-collection, quantification by culturing methods showed the integrated air sampler (i.e., GEM_VI) improved the collection of live E. coli by a median Concentration Factor (CF) of 1.59 and increased the recovery of viable human coronavirus OC43 (OC43) by a median CF of 12.7 as compared to the sampler without the VI. A comparison between reverse transcription and quantitative polymerase chain reaction and culturing methods showed that OC43 can be concentrated by the integrated air sampler without significant loss of infectivity. Data analysis by Kruskal-Wallis rank sum tests indicated that no significant differences existed between the small BioSpot-GEMTM and the larger BioSpot-VIVASTM for collection of live E. coli (p > 0.05), suggesting both the samplers had similar collection efficiencies. Our analyses show potential benefits toward improving the collection of viable pathogens from the air using a more portable water-based condensation air sampler, which can ultimately enable better characterization of health risks associated with airborne pathogen exposures.