Objectives: (i) To study fungal biodiversity on building materials in water-damaged houses (ii) To compare different building materials for resistance to fungal colonization (iii) To estimate efficacy of fungicidal disinfection of building materials Methods: Smears and scrapings from surfaces of damaged building materials were cultured on Sabouraud agar and malt agar plates for 20 days at 28 C and 37 C. Fungal isolates were identified by morphological features. Samples of not-damaged building materials (brick, gas concrete, expanded-clay concrete, gypsum board) were inoculated with a mixed suspension of fungal spores of seven mold species. The density of the suspension was 106 CFU ml)1. Samples were incubated in humid conditions at 28 C for 42 days and then examined for fungal growth. Surfaces of gypsum boards in a fungal damaged building were treated with fungicides (formalin, chlorine and guanidine derivatives, quaternary ammonium compounds) and sampled for fungal growth 2 weeks and 9 months after disinfection. Results: During 20062011 y.y. 360 water-damaged buildings were inspected. Penicillium spp. were most common on surfaces of all kinds of building materials. On brick surfaces the concentarions of Penicillium spp. were usually less than 300 CFU g)1. Aspergillus spp. also commonly grew on brick walls. Fungal species on sealant included Cladosporium spp., Fusarium spp., Aureobasidium pullulans, Penicillium spp., Rhodotorula spp. Paint, plaster and putty were usually colonized by Penicillium spp. (up to 30000 CFU g)1) and Aspergillus spp. (up to 10000 CFU g)1). Putty samples were also frequently damaged by Scopulariopsis brevicaulis and Acremonium spp. Inner side of vinyl wallpaper was commonly colonized by S. brevicaulis, Chaetomium globosum, Trichoderma spp., Stachybotrys chartarum. Experimental inoculation of clean building materials showed that expanded-clay concrete was most resistant to fungi and gypsum board was most susceptible to fungal growth in moist conditions. Disinfection of contaminated gypsum boards by different fungicidal agents was ineffective. Stachybotrys chartarum, Chaetomium globosum, Penicillium spp. were isolated from the surfaces and inner layers of gypsum boards in spite of fungicidal treatment. Conclusion: Wide spectrum of fungal species grow on building materials in water-damaged houses and may cause invasive mycoses, sensitization, toxic reactions. Gypsum board was most susceptible to fungal colonization. Potentially toxigenic species Stachybotrys chartarum and Chaetomium globosum could not be eliminated from damaged gypsum board by disinfection.
Full conference title:
Trends in Medical Mycology, 5th
- TIMM 5th (2013)