AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Determining the Recovery Efficiencies of Two Aerosol Samplers for Bacteria, Yeast, and Fungi
JOHN TROMBLEY, Jordan Bohannon, Jonathan Spurgin, Larry Bowen, Southern Research
Abstract Number: 431 Working Group: Aerosol Exposure
Abstract Two common methods of collecting bioaerosols for analysis are filtration and liquid impingement. During filtration, bacterial, viral and fungal particles are deposited onto the filter through impaction and interception. Liquid impingers utilize inertial impaction to deposit particles onto the body of the impinger and particle collection is enhanced through diffusion into the liquid. In this poster, we compared the recovery efficiencies of a custom designed, low-flow rate stainless steel liquid impinger and 47 mm gelatin filters for a variety of microorganisms consisting of a spore-forming bacteria (Bacillus anthracis Sterne), a non spore-forming bacteria (Acinetobacter baumannii), a yeast (Candida albicans) and a fungus (Aspergillus fumigates). Suspensions of each organism were aerosolized using a Collison 3-Jet Nebulizer and directed into a radial plenum. The plenum was ventilated at a constant 12 L/min bias flow rate which provided homogenous atmospheres for sampling. Liquid impingers were prepared with 50 mL phosphate buffered saline and gelatin filters were loaded into sterile filter holders prior to each test. Single liquid impinger and gelatin filer samples were collected simultaneously for 15 minutes from iso-axial sample ports on the radial plenum. Three suspension concentrations of each organism were tested. Following collection, each sample was analyzed in duplicate using standard microbiological methods. For B. anthracis Sterne and A. fumigates, greater recovery efficiencies were observed with the gelatin filters. For C. albicans, recovery efficiency was greater with gelatin filters but was nearly equivalent in two out of three tests. The recovery efficiency for A. baumannii was greatest when the liquid impinge was used with the exception of one test. Overall, the results demonstrate that the type of aerosol sampler used can significantly affect the recovery efficiencies of culturable microorganisms, potentially affecting aerosol concentration and dosimetry calculations.