Fungal aero-decontamination efficacy of mobile air-treatment systems

Abstract

Immunosuppressed patients are at high risk of acquiring airborne fungal infections, mainly caused by Aspergillus species. Although HEPA filters are recommended to prevent environmental exposure, mobile air-treatment units can be an alternative. However, many different models of mobile units are available but there are few data on their fungal aero-decontamination efficacy and usefulness in the prevention of Aspergillus infections. Thus, we developed a challenge test, based on the aerosolization of 10⁶ Aspergillus niger conidia, in order to compare the particle and fungal decontamination efficacy of the following four mobile air-treatment systems; Plasmair T2006, Mobil'Air 1200 (MA1200), Mobil'Air 600 (MA600) combined with Compact AirPur Mobile C250 (C250), and the prototype unit Compact AirPur Mobile 1800 (C1800). The use of all these air-treatment systems was able to significantly decrease the concentration of particles or fungal viable conidia. ISO7 was the maximum particle class reached within 20 min with the Plasmair T2006 and MA1200, 1 h by the combined MA600/C250, and 1 h and 30 min with the C1800. After 2 h, fungal counts were significantly lower with Plasmair T2006, MA1200 and the combined MA600/C250 (2.2 ± 1.9 to 5.0 ± 3.7 CFU/m³) than achieved with the C1800 (23.8 ± 12.8 CFU/m³; P ≤ 6.0E–3). All the air-treatment systems were able to decrease aerial particle and fungal counts, but their efficacy was variable, depending on the units’ air-treatment modalities and rates of air volume that was processed. This comparative study could be helpful in making an informed choice of mobile units, and in improving the prevention of air-transmitted fungal infections in non-protected areas.

Keywords:

• Mobile air-treatment units
• Aspergillus niger
• challenge tests
• particle and fungal counts
• aero-decontamination efficacy

Acknowledgements

The authors are grateful to Eric Jeanne for his participation to the realization of the tests, to Stéphanie Delvart and Dorothée Monvillers for their contribution to mycological analyses, and to Eduardo Dei-Cas for fruitful discussions on the experiment design and the manuscript. We also thank the mobile air-treatment units’ manufacturers (Airinspace, Air Medical Program, and PhotocleanQuartz) for providing air-treatment units and equipments during the experiments.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This paper was first published online on Early Online on 4 May 2011.