Direct assessment of microbial colonisation in damp houses by chemical marker analysis

Ergosterol was used as a marker of fungal biomass and 3-hydroxy fatty acids were used as markers of bacterial endotoxin to determine microbial colonisation of building materials by gas chromatography-mass spectrometry. Pieces (0.3-0.5 g) of materials from two water-damaged buildings were hydrolysed to liberate the markers from larger microbial structures; the preparations were then purified, derivatised, and analysed. The marker patterns obtained revealed that the microbial communities differed between the two buildings both qualitatively and quantitatively. The chemical-analytical method described should be useful for detecting and characterising microbial colonisation on surfaces in, for example, damp buildings.