Hemolysis, toxicity, and randomly amplified polymorphic DNA analysis of Stachybotrys chartarum strains

Stachybotrys chartarum is an indoor air, toxigenic fungus that has been ass ociated with a number of human and veterinary health problems. Most notable among these has been a cluster of idiopathic pulmonary hemorrhage cases th at were observed in the Cleveland, Ohio, area. In this study, 16 strains of S, chartarum isolated from case (n = 8) or control (n = 8) homes in Clevel and and 12 non-Cleveland strains from diverse geographic locations were ana lyzed for hemolytic activity, conidial toxicity, and randomly amplified pol ymorphic DNA banding patterns, In tests for hemolytic activity, strains wer e grown at 23 degrees C on wet wallboard pieces for an 8-week test period. Conidia from these wallboard pieces were subcultured on sheep's blood agar once a week over this period and examined for growth and clearing of the me dium at 37 or 23 degrees C. Five of the Cleveland strains (all from case ho mes) showed hemolytic activity at 37 degrees C throughout the 8-week test c ompared to 3 of the non-Cleveland strains. Five of the Cleveland strains, c ompared to two of the non-Cleveland strains, produced highly toxic conidia (>90 mu g of T2 toxin equivalents per g [wet weight] of conidia) after 10 a nd 30 days of growth on wet wallboard. Only 3 of the 28 strains examined bo th were consistently hemolytic and produced highly toxic conidia, Each of t hese strains was isolated from a house in Cleveland where an infant had idi opathic pulmonary hemorrhage.