Detection of biological aerosols by luminescence techniques

Luciferin-luciferase (LL) luminescence techniques were used to successfully measure the adenosine triphosphate (ATP) content (pg/ml) in aerosol sample s containing either vegetative bacterial cells or spores, Aerosols were col lected with wet or dry sampling devices. Evaluation for the presence of tot al biomass from both bacterial and nonbacterial sources of ATP was achieved by suspending the collected aerosol samples in phosphate-buffered saline ( PBS), using a pipette to draw off a 50-mu l aliquot of the PBS suspension i nto a Filtravette(TM), and then adding bacterial releasing agent (BRA), The sample was then reacted with LL, and the resulting relative luminescence u nits (RLUs), indicative of the total ATP content, were measured. Identical techniques were used to prepare the bacterial cells for analysis with one a dditional step: a wash with somatic cell releasing agent (SRA) before addin g BRA, This step removes interfering substances or nonbacterial sources of ATP, For spore analysis, an equivolume sample of the PBS suspension was add ed to an equivolume of trypticase soy broth (TSB), incubated at 37 degrees C for 15 min, and processed using methods identical to bacterial cell analy sis. With the use of these techniques we were able to detect Bacillus subti lis variation niger, formerly known as Bacillus globigii (BG) in artificial ly inoculated aerosol samples at concentrations greater than or equal to 10 (5) colony-forming units (CFU) per milliliter, Results of field and chamber trials show that one can detect the presence of bacterial and nonbacterial sources of ATP, These techniques may be appropriate to situations where th e measurement of bacterial aerosols is needed, (C) 1999 John Wiley & Sons, Inc.*