Bioaerosol collection efficiency and extraction from different filter materials using a Bacillus anthracis simulant.
Burton-NC; Adhikari-A; Grinshpun-SA; Reponen-T
Abstracts of the 1st National Conference on Environmental Sampling for Bio-Threat Agents, Baltimore, Maryland, January 27-28, 2005. Washington DC: Department of Homeland Security/Department of Defense, 2005 Jan; :1
A laboratory-based study was conducted to examine extraction efficiency and culturability using aerosolized Bacillus subtilis var. niger (BG) endospores as a surrogate for B. anthracis. Gelatin filters (3 um pore size), mixed cellulose ester (MCE) filters (3 um pore size), and polytetrafluoroethylene (PTFE) filters (of 1 and 3 um pore sizes), in conjunction with Button Inhalable Aerosol Samplers were used to collect endospores for 15-minute, 1-hour, and 4hour sampling periods. Physical collection efficiency (PCE) was determined by measuring the concentration of BG spores upstream and downstream of the filter sampler with an optical particle counter. Vortexing combined with ultrasonic agitation or shaker agitation extraction methods were compared in terms of extraction and culturability. Extraction fluid was plated on trypticase soy agar plates and colonies were counted after 18 hours incubation time. Total count was determined using an acridine orange staining method followed by epifluorescence microscopic counting. The gelatin, MCE, and 1 um PTFE, filters with the Button Inhalable Aerosol Samplers had PCEs of 94% or more. The 3 um PTFE filter with the Button Inhalable Sampler showed inconsistent efficiency characteristics between filters (64 +/- 32%), likely due to leakage around the filters, and was not used in the rest of the study. No statistically significant differences between the MCE, 1 um PTFE, and gelatin filters were found in the relative culturability (culturable count/total count) or physical extraction efficiency. MCE and 1 um PTFE had the best performance among the tested filters and are expected to be effective for the collection of B. anthracis samples.
Filters; Filtration; Laboratory-testing; Laboratory-work; Aerosols; Aerosol-sampling; Sampling; Sampling-methods
Abstract; Conference/Symposia Proceedings
Abstracts of the 1st National Conference on Environmental Sampling for Bio-Threat Agents, Baltimore, Maryland, January 27-28, 2005