Investigating the Effects of Fluid Composition on Bacterial Aerosol Production

 

Mathura Thirugnanasampanthar1, Rod G Rhem2, Myrna B Dolovich2,3 & Zeinab Hosseinidoust1,4,5

1McMaster University, Department of Chemical Engineering, 1280 Main Street West, Hamilton, ON, L8S 4L8, Canada

2St. Joseph’s Healthcare, Firestone Research Aerosol Laboratory, 50 Charlton Ave East, Hamilton, ON, L8N 4A6, Canada

3McMaster University, Faculty of Health Sciences, Department of Medicine, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada

4McMaster University, School of Biomedical Engineering, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada

5McMaster University, Micheal DeGroote Institute for Infectious Disease Research, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada

Summary

Airway lining mucus (ALM) is a complex hydrogel composed of 98% (w/v) water and 2% (w/v) solids content.1 Biological aerosols, including infectious aerosols, are believed to originate from shear-stress induced breakup of the ALM. Understanding how the composition and viscoelastic properties of the ALM affects infectious aerosol production can provide valuable insight into airborne transmission mechanisms. In this study we examined the effect of fluid composition on bacterial aerosol production. Solutions containing different concentrations of peptone water, a microbial growth medium rich in protein content, were used to suspend the bacterial pathogen, Staphylococcus aureus (S. aureus). Peptone water solutions were aerosolized using the single jet Blaustein Atomizer module. Polydisperse bacterial aerosols were size fractioned using a viable six-stage cascade impactor. Size and counts of bacterial aerosols generated from the three peptone water solutions were compared. Mean particle size of bacterial aerosols increased as the concentration of the peptone solution was increased from 1.5% (w/v) to 5.0% (w/v) and 10% (w/v) peptone content. Additionally, the number of bacterial aerosols generated from a 1.5% (w/v) peptone water solution was significantly greater as compared to the number of aerosols produced from a 10% (w/v) peptone water solution.

Key Message

Bacterial aerosols were generated from solutions formulated to mimic the solids concentration of the ALM. Significant changes in size and quantity of bacterial aerosols were observed as the concentration of the peptone water solution was altered, demonstrating the influence of fluid composition on the production of pathogen containing aerosols

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