Issue 1, 2007

Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH)

Abstract

Aerosols of water contaminated with Legionella bacteria constitute the only mode of exposure for humans. However, the prevention strategy against this pathogenic bacteria risk is managed through the survey of water contamination. No relationship linked the Legionella bacteria water concentration and their airborne abundance. Therefore, new approaches in the field of the metrological aspects of Legionella bioaerosols are required. This study was aimed at testing the main principles for bioaerosol collection (solid impaction, liquid impingement and filtration) and the in situ hybridization (FISH) method, both in laboratory and field assays, with the intention of applying such methodologies for airborne Legionella bacteria detection while showering. An aerosolization chamber was developed to generate controlled and reproducible L. pneumophila aerosols. This tool allowed the identification of the liquid impingement method as the most appropriate one for collecting airborne Legionella bacteria. The culturable fraction of airborne L. pneumophila recovered with the liquid impingement principle was 4 and 700 times higher compared to the impaction and filtration techniques, respectively. Moreover, the concentrations of airborne L. pneumophila in the impinger fluid were on average 7.0 × 105 FISH-cells m−3 air with the fluorescent in situ hybridization (FISH) method versus 9.0 × 104 CFU m−3 air with the culture method. These results, recorded under well-controlled conditions, were confirmed during the field experiments performed on aerosols generated by hot water showers in health institutions. This new approach may provide a more accurate characterization of aerobiocontamination by Legionella bacteria.

Graphical abstract: Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH)

Article information

Article type
Paper
Submitted
26 Jul 2006
Accepted
18 Oct 2006
First published
10 Nov 2006

J. Environ. Monit., 2007,9, 91-97

Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH)

M. Deloge-Abarkan, T. Ha, E. Robine, D. Zmirou-Navier and L. Mathieu, J. Environ. Monit., 2007, 9, 91 DOI: 10.1039/B610737K

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