Survival of Airborne Microorganisms During Swirling Aerosol Collection
An earlier study evaluated the physical performance of the Swirling Aerosol Collector, also known as the ''BioSampler,'' and found it to have several advantages over the widely used AGI-30 impinger when tested with inert test particles. The present study was focused on the physical and biological performance with laboratory-aerosolized micro-organisms. The results showed that the BioSampler has better physical collection efficiency for B. subtilis and P. fluorescens than the AGI-30 when water was used as the collection fluid and the sampling flow rate ranged from 8.5 L min-1 to the standard 12.5 L min-1. Additionally, the BioSampler provided equivalent or better microbial recovery for the 2 species than the AGI-30 did. The swirling motion of the collection liquid in the BioSampler generates very few bubbles and therefore causes minimal reen trainment of already collected micro-organisms. In contrast to the AGI-30, the BioSampler can be used very effectively with nonevaporating liquids, such as mineral oil or glycerol. Mineral oil was found to be a suitable collection fluid for culture analysis, whereas glycerol can be used only for nonculture assays, such as the polymerase chain reaction. By using a more viscous, nonevaporating fluid, the BioSampler can be used for long-term sampling of low airborne bacterial concentrations, while the AGI-30 impinger, filled with a standard evaporating fluid, can only be used for up to about 30 min.