Neisseria meningitidis is the causative agent of invasive meningococcal disease, a potentially fatal disease transmitted via respiratory aerosol that occurs across the globe with a particularly high mortality rate of 10%. Previous data we collected using CELEBS (Controlled Electrodynamic levitation and extraction of bioaerosol onto a substrate) on the airborne survival of N. meningitidis found there to be a rapid loss of bacterial viability over the first fifteen seconds after aerosolisation in artificial saliva.
However we have identified that survival is significantly increased and prolonged when aerosolised in human saliva samples. This was identified in Serogroup A, B and C N. meningitidis strains but not in the commensal strain Neisseria lactamica, suggesting a species-specific effect. Furthermore, this effect was seen across saliva samples from different donors.
We have also identified that the addition of different anti-oxidants significantly increases the survival of serogroup B strains, suggesting that oxidative stress is a mechanism that drives loss of bacterial viability in the air, as previously shown for E. coli (Oswin et al. 2023).Furthermore, removing the presence of small molecules from the real saliva via dialysis, including the antioxidant glutathione, resulted in a reduction in bacterial viability in aerosol.
Although further work must be completed to determine the mechanisms by which saliva may increase survival of N. meningitidis upon aerosolisation, this research will help to understand the dissemination of airborne pathogens and therefore how they may be contained.
Oswin, H. P., A. E. Haddrell, C. Hughes, M. Otero-Fernandez, R. J. Thomas, and J. P. Reid. 2023. 'Oxidative Stress Contributes to Bacterial Airborne Loss of Viability', Microbiol Spectr, 11: e0334722.