Growth Response of Stachybotrys Chartarum to Moisture Variation on Common Building Materials

Abstract

The mould Stachybotrys chartarum has been found to be associated with idiopathic pulmonary haemorrhage in infants and indoor exposure has also been linked to other pulmonary diseases, including allergies and asthma. S. chartarum has been studied both for toxin production and its occurrence in water-damaged buildings. Growth of S. chartarum on building materials such as gypsum wallboard has been frequently documented. Given that there may be a high frequency of occurrence and so the risk of exposure, environmental factors leading to the growth of S. chartarum have been studied. Samples of commonly used building materials were sterilised, inoculated with S. chartarum and exposed to controlled levels of relative humidity and wetting. A quantitative analysis of viable S. chartarum was performed on the building materials during a 7-month period. The results indicate that for environments with a relative humidity below total saturation, wetting was necessary for visible growth to occur. Conversely, high levels of relative humidity without wetting did not initiate growth. Porous materials, after becoming sufficiently wet and measuring saturation on a moisture meter, exhibited mould growth in every experiment conducted.

Keywords

Stachybotrys chartarum Biocontaminants Mould growth Gypsum Humidity

Get full access to this article

View all access options for this article.

References

1 Dearborn DG , Iwona Y , Sorenson WG , Miller MJ : Overview of investigations into pulmonary hemorrhage among infants in Cleveland, Ohio . Environ Hlth Perspect 1999;107 (Suppl. 3): 495–499 .

2 Vesper SJ , Vesper MJ : Stachylysin may be a cause of hemorrhaging in humans exposed to Stachybotrys chartarum . Infection and Immunity 2002;70(4): 2065–2069 .

3 Vesper SJ , Dearborn DG , Yike I , Allan T , Sobolewski J , Hinkley SF , Jarvis BB , Haugland RA : Evaluation of Stachybotrys chartarum in house of an infant with pulmonary hemorrhage: quantitative assessment before, during, and after remediation : J Urban Hlth 2000;77(1): 68–85 .

4 Scheel CM : Possible sources of sick building syndrome in a Tennessee middle school : Arch Environ Health 2001;56(5): 413–418 .

5 Sudakin DL: Stachybotrys chartarum: current knowledge of its role in disease. Medscape General Medicine, Veterans Administration Medical Center, Portland, Oregon, Feb 19, 2000, pE11, ISSN 1531–0132, Journal Code 100894134.

6 Murtoniemi T , Nevalainen A , Suutari M , Toivola M , Komulainen H , Hirvonen MR : Induction of cytotoxicity and production of inflammatory mediators in RAW264.7 macrophages by spores grown on six different plasterboards . Inhal Toxicol 2001;13(3): 233–247 .

7 Foarde KK , VanOsdell DW , Chang JCS : Static chamber method for evaluating the ability of indoor materials to support microbial growth: in: ASTM STP 1287, Characterizing Sources of Indoor Air Pollution and Related Sink Effects. Tichenor BA West Conshohocken, PA , 1996, pp 87–97.

8 Koch AL : Growth Measurement; in Gerhart P , Murray RGE , Wood WA , Krieg NR (eds): Methods for General and Molecular Bacteriology. Washington DC, American Society for Microbiology , 1994, pp 248–277.