Henry P Oswin, Evie Blake, Allen E Haddrell, Adam Finn, Shiranee Sriskandan, Jonathan P Reid, Alice Halliday, Anu Goenka
Microbiology (Reading, England) 2024 JanGroup A streptococcus (GAS) infections result in more than 500β000 deaths annually. Despite mounting evidence for airborne transmission of GAS, little is known about its stability in aerosol. Measurements of GAS airborne stability were carried out using the Controlled Electrodynamic Levitation and Extraction of Bioaerosols onto a Substrate (CELEBS) instrument. CELEBS measurements with two different isolates of GAS suggest that it is aerostable, with approximately 70β% of bacteria remaining viable after 20βmin of levitation at 50β% relative humidity (RH), with lower survival as RH was reduced. GAS airborne viability loss was driven primarily by desiccation and efflorescence (i.e. salt crystallization), with high pH also potentially playing a role, given reduced survival in bicarbonate containing droplet compositions. At low enough RH for efflorescence to occur, a greater proportion of organic components in the droplet appeared to protect the bacteria from efflorescence. These first insights into the aerosol stability of GAS indicate that airborne transmission of these respiratory tract bacteria may occur, and that both the composition of the droplet containing the bacteria, and the RH of the air affect the duration of bacterial survival in this environment. Future studies will explore a broader range of droplet and air compositions and include a larger selection of GAS strains.
Henry P Oswin, Evie Blake, Allen E Haddrell, Adam Finn, Shiranee Sriskandan, Jonathan P Reid, Alice Halliday, Anu Goenka. An assessment of the airborne longevity of group A Streptococcus. Microbiology (Reading, England). 2024 Jan;170(1)
PMID: 38180461
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