December 12th, 2017
Microbial toxins and eukaryotic cell toxicity from indoor building materials heavily colonized by fungi and bacteria were analyzed. The dominant colonizers at water-damaged sites of the building were Stachybotrys chartarum (103 to 105 visible conidia cm22), Penicillium andAspergillus species (104 CFU mg21), gram-negative bacteria (104 CFU mg21), and mycobacteria (103 CFU mg21). The mycobacterial isolates were most similar to M. komossense, with 98% similarity of the complete 16S rDNA sequence. Limulus assay of water extracts prepared from a water-damaged gypsum liner revealed high contents of gram-negative endotoxin (17 ng mg21 of E. coli lipopolysaccharide equivalents) and b-D-glucan (210 ng mg21 of curdlan equivalents). High-performance liquid chromatography analysis of the methanol extracts showed that the water-damaged gypsum liner also contained satratoxin (17 ng mg21). This methanol-extracted substance was 200 times more toxic to rabbit skin and fetus feline lung cells than extract of gypsum liner sampled from a non-water-damaged site. The same extract contained toxin(s) that paralyzed the motility of boar spermatozoa at extremely low concentrations; the 50% effective concentration was 0.3 mg of dry solids per ml. This toxicity was not explainable by the amount of bacterial endotoxin, b-D-glucan, or satratoxin present in the same extract. The novel in vitro toxicity test that utilized boar spermatozoa as described in this article is convenient to perform and reproducible and was a useful tool for detecting toxins of microbial origin toward eukaryotic cells not detectable in building materials by the other methods. Applied and Environmental Microbiology, Feb. 1997, p. 387–393, Vol. 63, No. 2