Endotoxin and β(1→3)-glucan in house dust and the relation with home characteristics:: A pilot study in 25 German houses

Residential microbial exposure has been suggested to be involved in the development of asthma. This paper describes bacterial endotoxin and mold beta(1-->3)-glucan levels in house dust and the relationship to selected home characteristics. Dust was sampled from mattresses and living room and bedroom floors of 25 houses in Germany. Endotoxin and beta(1-->3)-glucan levels ranged from 200-48,600 EU/g dust (100-32,900 EU/m(2) sampled surface) and 182-3,507 mu g/g (157-3,652 mu g/m(2)), respectively. Biocontaminant levels were highest on living room floors and lowest in mattresses. Dust, endotoxin and beta(1-->3)-glucan levels were 2-3 times higher on living room floors of centrally heated houses built after 1970 compared to older individually heated houses. This was not found for mattresses and bedroom floors. No associations between biocontaminant levels and other selected home characteristics (temperature, relative humidity, damp spots and insulation of windows) were found. beta(1-->3)-glucan levels were associated with total culturable fungi (per m(2)) in house dust, as well as with the fungal genus Alternaria (per g dust and per m(2)). In conclusion endotoxin and beta(1-->3)-glucan were readily detectable in house dust and significantly associated with heating system and/or age of the home.