A Comparative Analysis of Legionella pneumophila Infection Following Intranasal Instillation or Bioaerosol Inhalation

Current methodology for Legionella pneumophila infection studies often revolves around either 1) artificial administration using intranasal or intratracheal delivery, 2) semi-authentic delivery using bioaerosols and individual delivery systems (i.e. nose cones), or 3) the burgeoning field of authentic exposure scenarios using aerosol generating showerhead devices. Here, we propose an alternative to these methods in the use of a Madison Aerosol Chamber as a means of generating and delivering bioaerosols for an A/J mouse model. Using intranasal inoculation as a comparative, non-surgical delivery method, we show that bioaerosol delivery using the Aerosol Exposure Chamber is just as effective, with both infections following nearly equivalent dynamics with similar inocula. Mice in both groups also exhibited similar gene expression profiles following infection, with bioaerosol delivery generating a slightly more punctate expression. Taken together, this evidence shows that our system delivers similar, if not better, results than intranasal inoculation while allowing researchers to study bioaerosol generation and delivery mechanisms at the same time, factors that are critical when studying Legionella pneumophila infection.