Evaluation of quantitative PCR and culture methods for detection of house dust fungi and streptomycetes in relation to moisture damage of the house.

AIMS: Microbial concentrations in vacuumed house dust samples (n = 71) were analysed by culture and quantitative polymerase chain reaction (qPCR) methods and their association with extent of moisture damage in the house was studied. METHODS AND RESULTS: Microbial concentrations measured by qPCR correlated with concentrations obtained by culture method, but were orders of magnitude higher. qPCR also had better sensitivity. Concentrations of several microbes in house dust, determined with qPCR, were associated with the extent of moisture damage in the house. This association was strongest for Penicillium brevicompactum, one of the fungi detected in highest concentrations by qPCR. Furthermore, house dust concentrations of Wallemia sebi, Trichoderma viride, Cladosporium sphaerospermum, Eurotium amstelodami and the combined assay group for Penicillium spp., Aspergillus spp. and Paecilomyces variotii were significantly associated with the extent of the moisture damage. CONCLUSION: These species or assay groups could probably be used as indicators of moisture damage in the house. SIGNIFICANCE AND IMPACT OF THE STUDY: This finding indicates the benefits of the qPCR method, which is sensitive enough to reveal the differences in microbial concentrations of house dust between moisture-damaged and undamaged houses.