AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Effect of Season and Environmental Parameters on Assemblages of Airborne Bacteria and Fungi in Mexico City
GEDIMINAS MAINELIS, Valdis Krumins, M. Hernandez, Jose Angeles, Victor Paramo-Figueroa, Martha Torres, Stephan Schwander, Rutgers, The State University of New Jersey
Abstract Number: 633 Working Group: Bioaerosols
Abstract Earlier studies showed that exposure to ambient PM adversely affects protective human immune responses against M. tuberculosis, the causative agent of tuberculosis, possibly confounded by co-exposure to airborne microorganisms. Here we investigated the composition of airborne microbe assemblages in PM in a densely populated Iztapalapa municipality of Mexico City in 2016/2017.
Duplicate PM10 samples were collected weekly for 24 hours at the height of 18 m using Impact Samplers (SKC Inc.) operated at 10 L/min. The accumulated microbial DNA was extracted and submitted to Molecular Research Laboratory (Shallowater, TX) for analysis of the 16S ribosomal RNA gene for prokaryotes and the internal transcribed spacer (ITS) region for fungi.
More than 3200 species of fungi in 150 orders (22 phyla) and more than 5000 species of bacteria belonging to 300 orders (50 phyla) were detected at highly varying relative abundances. More than 80% of bacterial communities were comprised of Actinobacteria, Proteobacteria, and Firmicutes. Forty percent of fungal reads belonged to orders identified as sooty mold, with Cladosporium spp. comprising ~40% of its genera; order Pleosporales, the majority species of which feed on decayed organic matter, comprised ~10% of reads; other major orders included Agaricales, Eurotiales, Polyporales, Hypocreales, and Xylariales (each >3%).
Principal coordinates analysis (PCoA) revealed seasonal effects (rainy vs. dry) and weather effects (rain/no rain during sampling) on the composition of the bacterial and fungal communities. Temperature, wind speed and direction, and relative humidity were weak predictors of microbial diversity. The ongoing data analysis is focusing on microbial diversity and richness indices and health-relevant species.
These preliminary data suggest that the makeup and abundance of microbes should be taken into account when analyzing exposures and potential health effects of outdoor PM.
Funding: NIEHS:R01ES020382 (S. Schwander), NIH-NIEHS:P30 ES005022, CEED pilot grant (S. Schwander, G. Mainelis).