Evaluation of media for detection of Stachybotrys and Chaetomium species associated with water-damaged buildings

Stachybotrys chartarum and Chaetomium globosum are two important species colonising wet building materials containing cellulose. Both species produce toxic metabolites in pure cultures as well as on arti cially inoculated building materials, so detection is important. However, the media recommended for detection of fungi in buildings, DG18 (dichloran 18% glycerol agar), MEA (malt extract agar) and Water agar, are ine ective. Furthermore, contact plates should be used instead of air sampling, because the spores of S. chartarum and C. globosum do not readily become air-borne. Therefore, 22 mycological media were tested and evaluated according to colony size, colony density and sporulation density of 14 test isolates. Amongst the 14 isolates (nine Stachybotrys, four Chaetomium and one Memnoniella) used in this study, eight came from Danish water-damaged buildings. The results showed that none of the 14 isolates sporulated on DG18 and that growth was very restricted. On MEA the fungi were inhibited in their growth and only one-third of the isolates sporulated. Only media containing some kind of plant-based ingredient resulted in good growth and sporulation. At present V8, with antibiotics in the form of contact plates, seems to be the best choice of medium out of the 22 tested for detection of S. chartarum and C. globosum species found in water-damaged buildings