engleski

Toxicity of indoor Stachybotrys chartarum

The toxigenic mould Stachybotrys chartarum has been reported to cause animal and human toxicoses, including fatal ones of babies living in contaminated buildings. During a 5-year study of indoor fungal colonization of mouldy buildings in Slovakia, 147 wall scrapings, house dust and air samples were collected, while only 7 isolates of S. chartarum were recovered. They were able to produce active secondary metabolites also on the building materials (plaster- cardboard and 6 types of cement and lime plasters in wet chambers at 25 °C for 14 ? 90 d) in previous in vitro toxicological studies. In vitro respiratory toxicity (ceasing of chick tracheal ciliary beating and activity of alkaline phosphatase in the rat lung epithelial type II cells in 3 d) as well as in vivo toxicity of the complex mixtures of chloroform-extractable metabolites of a S. chartarum strain ? atranone chemotype (detected by thin layer chromatography) isolated from a mouldy office in Bratislava, SK, after the intratracheal instilation (4 ?g) in Wistar male rats (ca. 200 g) was evaluated. Histological changes (by autopsy and lectinhistochemistry), hematological parameters (leukocyte, erythrocyte and thrombocyte cell counts, hemoglobin and hematocrit), cytotoxic (phagocytic activity and viability of alveolar macrophages (AM), lactate dehydrogenase and acid phosphatase activities) and inflammatory response biomarkers (total cell counts, number of AM, granulocyte and AM differentials) were measured in blood or the bronchoalveolar lavage fluid (BALF) after 3 d. The exometabolites showed higher in vitro activity than endometabolites, especially when originated from the fungal growth on building materials (plasterboard). No significant inflammatory changes of lung tissue, but fragmentation and coarsing of T II lung cell memebrane were found. The exometabolites also proved to be erythrocyte suppressors and siderophores. They caused severe injury of upper and lower airways (cytotoxic ? decreased AM viability, though no significant changes of phagocytic activity, and inflammation inducing ? increased total cell counts, proportion of binuclear cells and of young monocytic AM form, while decreased AM count as well as its proportion in the BALF - activity), too. Anyway, risk assessment to humans requires further studies on dose ? effect relationship, pulmonary deposition characteristics of fungal particles and chronic exposure.

Stachybotrys chartarum; indoor spaces; citotoxicity

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