Airborne microbial contamination in indoor environments - comparison of sampling technologies for enumeration by cultivable method

Farru G.

First

;Pavard G.;Joubert A.;Le Cann P.;Andres Y.

2020-01-01

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Abstract

The aim of this study was to compare different sampling methods to investigate the presence of airborne cultivable microorganisms in indoor environments: impaction, impingement and filtration, before enumeration by cultivable method. Microbial aerosol measurements were carried out in 3 different indoor environments: classroom A in a high-efficiency building, classroom B in a low-efficiency building and office C. Three air sampling devices were used: an impaction-based device, the MAS-100NT (MBV), an impinger-based, the BioSampler (SKC) and two filters, cellulose nitrate filter (Sartorius) and fibrous filters (Lydall) requiring microorganisms liquid extraction from the filter before counting. Concentrations of the total cultivable airborne bacteria and fungi ranged from 20 to over 1000 CFU/m3. The highest airborne microbial concentration was observed in classroom A with ventilation off. The results showed that the impaction-based method was the most suitable for microbial aerosol sampling in indoor environments when followed by CFUs count. It enables to collect a greater number of cultivable microorganisms, compared with impingement or filtration with fibrous filter. Avoiding the transfer to liquid phase, more microorganisms are collected and can grow. Good results were achieved with filtration using cellulose filters without extraction phase.