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Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels
Author(s) -
Cai G.H.,
Bröms K.,
Mälarstig B.,
Zhao Z.H.,
Kim J. L.,
Svärdsudd K.,
Janson C.,
Norbäck D.
Publication year - 2009
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/j.1600-0668.2009.00600.x
Subject(s) - allergen , fungal diversity , penicillium , odor , alternaria , contamination , veterinary medicine , aspergillus , biology , toxicology , microbiology and biotechnology , food science , medicine , horticulture , ecology , immunology , allergy , neuroscience
Sweden has had allergen‐avoidance day care centers (AADCs) since 1979. The aim of this study was to measure fungal DNA by quantitative polymerase chain reaction (qPCR), a new method, in AADCs and ordinary day care centers (ODCs) and examine associations between allergen levels and building characteristics. Dust samples were collected by swabbing doorframes, vacuum‐cleaning, and using Petri dishes. In total, 11 AADCs and 11 ODCs were studied (70 rooms). Total fungal DNA, measured by qPCR in the swab dust, was detected in 89%, Aspergillus or Penicillium ( Asp/Pen ) DNA in 34%, and Stachybotrys chartarum DNA in 6% of the rooms. Total fungal DNA was significantly higher in rooms with linoleum floor ( P = 0.02), textile carpets ( P = 0.03), reported dampness/molds ( P = 0.02) and reported odor ( P < 0.001) in the buildings, and significantly lower in wooden facade buildings ( P = 0.003). Reported odor was related to the amount of sieved fine dust, reported dampness/molds and type of building construction. Total fungal DNA was related to cat, dog, horse and total allergen levels ( P = 0.003) in the day care centers. In conclusion, total fungal DNA is related to reported dampness/molds, reported odor, and type of wall construction. The association between fungal and allergen contamination indicated a general ‘hygiene factor’ related to biological contaminants. Practical Implications The associations between fungal DNA, reported dampness/molds, and odor support the view that buildings with odor problems should be investigated for possible hidden fungal growth. There is a need to measure fungal biomass in different types of building constructions by monitoring fungal DNA. Analysis of fungal DNA with quantitative PCR can be a fast and practical way to study indoor fungal contamination. Swabbing dust from the doorframe of the main entrance to the room can be a convenient method of sampling dust for fungal DNA analysis. The high prevalence of reported dampness/molds and the common occurrence of fungal DNA indicate the need to improve the indoor environment of Swedish day care centers.