MOLECULAR GENETIC CHARACTERIZATION OF MICROBES IN INDOOR AND OUTDOOR AIR AND DUST:

PRINCIPAL INVESTIGATOR:
Professor James Scott
Dalla Lana School of Public Health
University of Toronto
223 College St. Toronto ON M5T 1R4
Tel. 416-946-8778

CO-INVESTIGATORS:
Becker AB, Brook J, Escobar M, Guttman D, Kozyrskyj AL, Scott JA, Silverman F, Takaro T

TRAINEES:
Azad M (postdoc), Du S (Technician), Konya T (MPH student), Koster BM (postdoc), Maughan H (postdoc)

RESEARCH PARTNERS:
Sporometrics Inc.

SPONSOR:
AllerGen Network of Centres of Excellence; CIHR; Canadian Healthy Infant Longitudinal Development (CHILD) Study

PURPOSE OF THE STUDY:
This project uses high-throughput next generation DNA sequencing to characterize airborne and dust-borne microbes. Microbial community profiles will then be analysed in comparison to the human microbiome composition and measures of health and of the building occupants.

BACKGROUND:
Exposures to fine particles occur in both outdoor and indoor environments. Increasing evidence suggests that indoor and outdoor air exposures play an important role in the development and/or exacerbation of airway and cardiovascular diseases. Particles of biological origin may be important contributors to these effects. Measurement of signature biochemicals has revealed that up to one quarter of the organic carbon fraction of submicroscopic particles in outdoor air are of biological origin (Womiloju et al. 2003. Atmos Environ 37: 43354344). The magnitude of the biological fraction of fine particulate matter may be even larger in the indoor environment where house dust is known to serve as both a major reservoir and growth site of microbes. In both the outdoor and indoor setting, there is a lack of detailed information on the relative contribution of different microbial species to biological fine particulate matter. This information cannot be estimated reliably by routine microscopy or culture methods, yet it is vital to a complete understanding of the sources and fates of these particles, their human exposure pathways, and the nature and magnitude of the hazards that these particles pose.

METHODS:
Modern molecular genetic techniques such next generation DNA sequencing have revolutionized the characterization and comparison of complex polymicrobial communities in a wide range of biological systems from agricultural soils to deep sea thermal vents. We are using this method to the study of microbes in indoor and outdoor air and dust will yield similarly fruitful results. The novel application of both techniques to the study of these health-relevant biological particles in indoor and outdoor air and dust offers an innovative, modern approach to characterizing the microbial compositions of bioaerosols and dusts. Genetic methods do not require intact cells and time-consuming, costly culturing procedures. Also, unlike culture-based methods, genetic methods are able to detect and characterize DNA attached to very fine particles consisting of comminuted cells.

STUDY CONTACT:
For more information on the study, contact: