Inhibition of quantitative PCR analysis of fungal conidia associated with indoor air particulate matter.
McDevitt-JJ; Lees-PSJ; Merz-WG; Schwab-KJ
Aerobiologia 2007 Jan; 23(1):35-45
Environmental samples analyzed by quantitative PCR (qPCR) are subject to interference by inhibitors present in the environment being sampled. A controlled determination of the effect of inhibitors associated with sampling indoor air and the ability of internal standard controls to detect inhibition was carried out by filter collection of air samples followed by spiking of the filters with green fluorescent protein-expressing Aspergillus fumigatus conidia. Microscopic conidial counts were compared with qPCR results and correlated with levels of particulate matter and viable airborne microorganisms. Our data showed that PCR can be inhibited by masses of particulate matter as low as 50 µg and that the amount of inhibition was positively correlated with the mass of particulate (r = 0.75) and the number of non-filamentous organisms (r = 0.73). The use of internal standard DNA identified the presence of inhibitors and indicated the need for additional sample processing or qualification of sample results.
Fungi; Environmental-factors; Air-samples; Airborne-particles; Analytical-processes; Analytical-methods; Particulates; Particulate-sampling-methods; Sampling; Sampling-methods; Microorganisms;
Author Keywords: Airborne fungi; Aspergillus fumigatus; Conidia; Quantitative PCR; Particulate-matter; Sample inhibition
K. J. Schwab, Department of Environmental Health Sciences, The Johns Hopkins University, Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205, USA
Johns Hopkins University