ARE Labs is proud to support MRI Global in the Design, Development, Characterization and Execution of Bioaerosol a Vaccine Efficacy Study for Burkholderia mallei (glanders).  The program was funded by Biomedical Advanced Research and Development Authority (BARDA).  ARE Labs provided critical study support which included the design and construction of a 12 port nose-only exposure system (murine animal model), validation and characterization of the exposure system with B. mallei, conduct of the  exposures, and data analysis and reporting.

The system was constructed in MRI Global’s BL3 safety Laboratory in a biological safety cabinet glove box.  Flow monitoring and control systems were implemented for ease of adjustment, monitoring, and recording of system operation parameters.  Following construction, the primary containment system and the aerosol challenge system were leak tested at positive pressure conditions with cabinet and system seals and penetrations monitored for leaks with smoke and liquid leak detectors. The aerosol generation, sampling system, flow controllers, and monitors were characterized and calibrated with a certified NIST traceable flow standard and results graphed for documentation.  The system was characterized for aerosol generation, delivery, and exposure concentration homogeneity using NIST traceable polystyrene latex microsphere (PSL) standards of 1.0, 2.0, and 3.0 μm in diameter with each standard prepared individually in molecular grade water.   The PSL standards were aerosolized in independent tests using a Collison nebulizer with the system operating in a dynamic flow through mode at flow and pressures defined to conduct the exposure study.

The exposure system was operated in a dynamic push/pull flow mode at slight negative pressure.  A TSI Aerodynamic Particle Sizer (APS) was used to measure the particle size distribution and count concentration homogeneity of at each of the twelve exposure locations of the nose only exposure system.   The APS data was regressed and concentrations and particle size for each of the PSL standards were verified to be within ± 2% of the median concentration for aerosol delivery at each exposure location.  Following the system characterization, we performed a pilot study to measure the viable aerosol system delivery and collection concentrations of B. mallei standards prepared at concentrations of 1 x 104, 1 x 106, and 1 x 108 colony forming units per mL (cfu/mL).  Aerosol characterization trials for each of the three B. mallei standards were conducted in triplicate.  Impinger samples were taken at a nose only aerosol delivery location of the system during each trial, and collected samples were serial diluted on agar plates, incubated for 48 to 72 hours, and enumerated for viable cfu collection to define the presented dose and exposure parameters for the study.