Ultraviolet germicidal irradiation disinfection of Stachybotrys chartarum

• Published in: Canadian journal of microbiology Vol. 51; no. 9; pp. 801 - 804
• Main Authors: Green, Christopher F, Davidson, Craig S, Scarpino, Pasquale V, Gibbs, Shawn G
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.09.2005; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Biological and medical sciences; Colony Count, Microbial; Culture Media; Disease control; Disinfection - methods; Dose-Response Relationship, Radiation; Environmental engineering; Fluctuations; Fundamental and applied biological sciences. Psychology; Hair loss; Hay fever; Health hazards; Inactivation; Indoor air quality; Infectious diseases; Irradiation; Light; Mercury; Microbiology; Mold; Mycological methods and techniques used in mycology; Mycology; Sick building syndrome; Spores, Fungal - radiation effects; Stachybotrys - growth & development; Stachybotrys - physiology; Stachybotrys - radiation effects; Stachybotrys chartarum; Ultraviolet radiation; Ultraviolet Rays; Ventilation; Fungi; Antifungal agent; Ultraviolet irradiation; Stachybotrys chartarum; Disinfection; Fungi Imperfecti; Thallophyta
• ISSN: 0008-4166; 1480-3275
• DOI: 10.1139/w05-061

The ultraviolet germicidal irradiation (UVGI) dose necessary to inactivate fungal spores on an agar surface and the efficacy of UVGI were determined for cultures of Stachybotrys chartarum (ATCC 208877). This study employed a UVGI testing unit consisting of four chambers with a 9-W, Phillips, low pressure, mercury UVGI lamp in each chamber. The testing unit's apertures were adjusted to provide 50, 100, 150, and 200 µW/cm 2 of uniform flux to the Petri dish surfaces, resulting in a total UVGI surface dose ranging from 12 to 144 mJ/cm 2 . The UVGI dose necessary to inactivate 90% of the S. chartarum was greater than the maximum dose of 144 mJ/cm 2 evaluated in this study. While UVGI has been used to inactivate several strains of culturable fungal spores, S. chartarum was not susceptible to an appropriate dose of UVGI. The results of this study may not correlate directly to the effect of UVGI on airborne fungal spores. However, they indicate that current technology may not be efficacious as a supplement to ventilation unless it can provide higher doses of UVGI to kill spores, such as S. chartarum, traveling through the irradiated zone.Key words: Stachybotrys chartarum (synonyms S. atra, S. alternana), ultraviolet germicidal irradiation, fungi.