A vibrating mesh nebulizer as an alternative to the Collison 3-jet nebulizer for infectious disease aerobiology

Abstract

17Experimental infection of animals via inhalation containing pathogenic agents is essential to 18 understanding the natural history and pathogenesis of infectious disease as well as evaluation of 19 potential medical countermeasures. We evaluated whether the Aeroneb, a vibrating mesh 20 nebulizer, would serve as an alternative to the Collison, the 'gold standard' for generating 21 infectious bioaerosols. While the Collison possesses desirable properties that have contributed to 22 its longevity in infectious disease aerobiology, concerns have lingered about the volume and 23 concentration of agent required to cause disease and the damage that jet nebulization causes to 24 the agent. For viruses, the ratio of aerosol concentration to nebulizer concentration (spray factor, 25 SF), the Aeroneb was superior to the Collison for four different viruses in a nonhuman primate 26 head-only exposure chamber. Aerosol concentration of influenza was higher relative to 27 fluorescein for the Aeroneb compared to the Collison, suggesting that the Aeroneb was less 28 harsh to viral pathogens than the Collison when generating aerosols. The Aeroneb did not 29 improve the aerosol SF for a vegetative bacterium, Francisella tularensis. Environmental 30 parameters collected during the aerosols indicated that the Aeroneb generated a higher relative 31 humidity in exposure chambers while not affecting other environmental parameters. Aerosol 32 mass median aerodynamic diameter was generally larger and more disperse for aerosols 33 generated by the Aeroneb than what is seen with the Collison but ≥80% were within the range 34 that would reach the lower respiratory tract and alveolar regions. These data suggest that for viral 35 pathogens, the Aeroneb is a suitable alternative to the Collison 3-jet nebulizer. 36 Importance 37 The threat of aerosolization is often not the natural method of transmission. While selection of 38 an appropriate animal model is vital for these types of experiments, other confounding factors 39 can be controlled through a thorough understanding of experimental design and the effects that 40 different parameters can have on disease outcome. Route of administration, particle size, and 41 dose are all factors which can affect disease progression and need to be controlled. Aerosol 42 research methods and equipment need to be well characterized to optimize the development of 43 animal models for bioterrorism agents.44 45 65responses that protect the host. These effects could raise the dose required to cause disease, 66 thereby requiring large quantities of pathogens grown to high titers for aerosol experiments. 67While the process of aerosolization will always place mechanical stress on infectious agents, 68 aerosol generators that are 'gentler' than the Collison would be desirable. 69The Aerogen Solo (a.k.a Aeroneb) is a single-use nebulizer employed in clinical settings 70 for the delivery of aerosolized medication. The Aeroneb utilizes a palladium mesh perforated 71 with conical shaped holes that act as a micropump...

Comparison of three air samplers for the collection of four nebulized respiratory viruses ‐ Collection of respiratory viruses from air –

“…In general, it should be mentioned, however, that experimental set‐ups including nebulizer type, collection medium, and the applied flow rate are not uniform among studies. As an alternative to a jet nebulizer, which is often used in similar studies, here, a vibrating mesh nebulizer was used, as this nebulizer was shown to preserve the infectivity of viruses better than a jet nebulizer 42 . Comparing the amount of infectious virus and viral RNA before and after nebulization in the present study showed that the virus solution was almost completely nebulized by the device and that the infectivity of viruses was well preserved.…”

“…Comparing the amount of infectious virus and viral RNA before and after nebulization in the present study showed that the virus solution was almost completely nebulized by the device and that the infectivity of viruses was well preserved. It should be noted that the nebulizer creates a higher relative humidity compared to a jet nebulizer and that in the current study aerosols and droplets were directly nebulized into a small chamber (11.5 L) 42 . In other studies, a dryer is often added to the experimental set‐up that further dries aerosols and droplets before entering a collection chamber and thereby further decreasing particle sizes 49 .…”

“…Air samplers were connected to a chamber (Nalgene BioTransport Carrier box, 11.5 L, dimensions 36,8 × 18,4 × 17,0 cm (L × W × H)), in which 500 µl of a virus suspension was nebulized using the Aerogen Solo (Medicare Uitgeest B.V.). The Aerogen Solo is a vibrating mesh nebulizer that uses electricity to produce aerosols and droplets between 1 and 5 µm, with a reported mass median aerodynamic diameter of 3.05 µm, when nebulized in a 12 L chamber 41,42 . The vacuum pump was switched on just before nebulization and air was drawn through the air samplers for a total of 5 min (Figure 2B).…”

New insights into the standard method of assessing bacterial filtration efficiency of medical face masks

“…Recent studies on bioaerosol generation [14][15][16][17][18] used a modern vibrating mesh nebulizer as an alternative to older jet nebulizers (such as the collision jet) that have been used for decades to perform BFE tests. Consequently, the E-Flow mesh nebulizer (Pari GmbH, Starnberg, Germany) provided aerosolization of 3.0 ± 0.3 µm droplets from a 3-mL suspension with 3000 CFU/mL of S. aureus.…”

Aerosolization and recovery of viable murine norovirus in an experimental setup

“…Evaluations of viral infectivity after aerosolization have been performed in previous studies 1, [10][11][12][13][14][15][16][17] . Yet, many of these studies lack a detailed representation of the generated aerosol, such as size characterization from nanometer to micrometer sized aerosol particles, physical dilution factor (or spray factor) of the setup, and the effect of drying on particle size 18 .…”