Detection of airborne microbes using a novel ambient air sampling device

Rationale
Aerosolised particles of biological origin (bioaerosols) including bacteria, viruses, fungi and their derivatives, pose risks to public and occupational health, including disease transmission, asthma and allergy. Bioaerosol detection is important in multiple indoor environments where there is elevated risk of exposure.
AIM: to demonstrate the use of a high volume ambient air sampler (AAS) with noise-less operation for the detection of airborne microorganisms.
Methods
Bacterial strains Staphylococcus aureus, Klebsiella pneumoniae, Listeria innocua and Escherichia coli, and the bacteriophage MS2 were aerosolised within a test chamber. Air was sampled using the AAS. Filters were extracted and microbes were quantified using culture-based techniques (viable counts) and qPCR (total counts).
Results
Viable bacterial and viral particles were quantified from AAS filters following 1-minute sampling. From 109 colony forming units (CFUs) aerosolised into the chamber, 105 CFU/m3 of K. pneumoniae, S. aureus and L. innocua and 104 CFU/m3 of E. coli were recovered. From 1010 plaque forming units (PFU) of MS2 aerosolised, 106 PFUs/m3 were recovered. Using qPCR for quantification, longer duration sampling and higher microbial collection was achieved. From 109 CFU aerosolised into the chamber, 106 bacteria/m3 were recovered following 60-minute sampling for S. aureus and K. pneumoniae.
Conclusions
This pilot study demonstrates the ability of the AAS to sample a variety of bioaerosol constituents which can impact human health. The AAS provides a user-friendly solution for routine monitoring of bioaerosol exposure within indoor environments.