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Quantitative PCR analysis of house dust can reveal abnormal mold conditions
Teija Meklin1, Richard A Haugland, Tiina Reponen
1National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH 45268, USA.
Abstract:
Indoor mold concentrations were measured in the dust of moldy homes (MH) and reference homes (RH) by quantitative PCR (QPCR) assays for 82 species or related groups of species (assay groups). About 70% of the species and groups were never or only rarely detected. The ratios (MH geometric mean : RH geometric mean) for 6 commonly detected species (Aspergillus ochraceus, A. penicillioides, A. unguis, A. versicolor, Eurotium group, and Cladosporium sphaerospermum) were >1 (Group I). Logistic regression analysis of the sum of the logs of the concentrations of Group I species resulted in a 95% probability for separating MH from RH. These results suggest that it may be possible to evaluate whether a home has an abnormal mold condition by quantifying a limited number of mold species in a dust sample. Also, four common species of Aspergillus were quantified by standard culturing procedures and their concentrations compared to QPCR results. Culturing underestimated the concentrations of these four species by 2 to 3 orders of magnitude compared to QPCR.
Insights
Quantifying specific indoor mold species in dust using quantitative PCR (QPCR) can identify moldy homes. This method accurately distinguishes homes with abnormal mold conditions from reference homes.
Area of Science:
- Environmental Science
- Microbiology
- Indoor Air Quality
Background:
- Indoor mold exposure is a health concern.
- Accurate quantification of indoor mold species is challenging with traditional methods.
Purpose of the Study:
- To evaluate quantitative PCR (QPCR) for measuring indoor mold concentrations.
- To identify specific mold species that can serve as indicators of moldy homes (MH).
Main Methods:
- Quantitative PCR (QPCR) assays were used to measure 82 mold species in dust from moldy homes (MH) and reference homes (RH).
- Logistic regression analysis was performed on the concentrations of commonly detected mold species.
- Standard culturing methods were compared to QPCR for quantifying four common Aspergillus species.
Main Results:
- Approximately 70% of mold species were rarely detected.
- Six species (Aspergillus ochraceus, A. penicillioides, A. unguis, A. versicolor, Eurotium group, Cladosporium sphaerospermum) showed higher concentrations in MH than RH.
- Logistic regression using these six species achieved 95% probability in separating MH from RH.
- QPCR results for Aspergillus species were 2-3 orders of magnitude higher than those obtained by culturing.
Conclusions:
- Quantifying a limited set of indoor mold species via QPCR can effectively differentiate moldy homes.
- QPCR offers a more sensitive and comprehensive method for indoor mold assessment compared to traditional culturing.
