title: Culturability of Bacillus spores on aerosol collection filters exposed to airborne combustion products of Al, Mg, and B·Ti.
abstract: Destruction of bioweapon facilities due to explosion or fire could aerosolize highly pathogenic microorganisms. The post-event air quality assessment is conducted through air sampling. A bioaerosol sample (often collected on a filter for further culture-based analysis) also contains combustion products, which may influence the microbial culturability and, thus, impact the outcome. We have examined the interaction between spores deposited on collection filters using two simulants of Bacillus anthracis [B. thuringiensis (Bt) and B. atrophaeus (referred to as BG)] and incoming combustion products of Al as well as Mg and B·Ti (common ingredient of metalized explosives). Spores extracted from Teflon, polycarbonate, mixed cellulose ester (MCE), and gelatin filters (most common filter media for bioaerosol sampling), which were exposed to combustion products during a short-term sampling, were analyzed by cultivation. Surprisingly, we observed that aluminum combustion products enhanced the culturability of Bt (but not BG) spores on Teflon filters increasing the culturable count by more than an order of magnitude. Testing polycarbonate and MCE filter materials also revealed a moderate increase of culturability although gelatin did not. No effect was observed with either of the two species interacting on either filter media with products originated by combustion of Mg and B·Ti. Sample contamination, spore agglomeration, effect of a filter material on the spore survival, changes in the spore wall ultrastructure and germination, as well as other factors were explored to interpret the findings. The study raises a question about the reliability of certain filter materials for collecting airborne bio-threat agents in combustion environments.
authors.affiliation: Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA; Department of Environmental Health Sciences, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA.
authors.forename: Atin
authors.initials: A
authors.lastname: Adhikari
authors.affiliation: Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Yermakov
authors.affiliation: Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA.
authors.forename: Reshmi
authors.initials: R
authors.lastname: Indugula
authors.affiliation: Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA.
authors.forename: Tiina
authors.initials: T
authors.lastname: Reponen
authors.affiliation: Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL 60153, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Driks
authors.affiliation: Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA. Electronic address: sergey.grinshpun@uc.edu.
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Grinshpun
mesh_terms: D000336:Aerosols; D061808:Air Filters / Q000382:microbiology*; D000535:Aluminum / Q000494:pharmacology*; D001407:Bacillus / Q000187:drug effects / Q000302:isolation & purification* / Q000502:physiology; D001408:Bacillus anthracis / Q000302:isolation & purification / Q000502:physiology; D001413:Bacillus thuringiensis / Q000302:isolation & purification / Q000502:physiology; D023482:Bioterrorism; D001895:Boron / Q000494:pharmacology; D005390:Fires; D008274:Magnesium / Q000494:pharmacology; D050296:Microbial Viability / Q000187:drug effects; D008962:Models, Theoretical; D013171:Spores, Bacterial / Q000187:drug effects / Q000302:isolation & purification*; D014025:Titanium / Q000494:pharmacology
chemical_list: D000336:Aerosols; D000535:Aluminum; D014025:Titanium; D008274:Magnesium; D001895:Boron
keywords: Air sampling; Anthrax spores; Bio-threat; Bioaerosol