Air Date: 12-4-2015| Episode: 393
A hot topic in the research community is the microbiome of the built environment. This week on IAQ Radio we welcome one of the leading researchers in this area Dr. Jordan Peccia…
A hot topic in the research community is the microbiome of the built environment. This week on IAQ Radio we welcome one of the leading researchers in this area Dr. Jordan Peccia. Dr. Peccia is an Associate Professor of environmental engineering at Yale University, the director of Yale environmental engineering’s undergraduate studies, and the faculty advisor for Yale Engineers Without Borders. He is an associate editor for the journal Indoor Air, and is the 2014-15 chair of the Indoor Aerosols and Aerosol Exposure working group for the American Association for Aerosol Research. Research in the Peccia lab integrates microbiology with engineering to address important contemporary environmental problems. The principle areas of research include: (i) human exposure to bacterial and viral pathogens emitted during the land application of sewage sludge, (ii) the sources of and human exposure to bacteria and fungi in the indoor environment, and (iii) genome-wide gene expression investigations for improving biofuel feedstock production rates in photosynthetic microorganisms. He holds degrees in mechanical engineering (BS) and environmental engineering (MS) from Montana State University, and received his PhD in Environmental Engineering from the University of Colorado in the year 2000. LEARN MORE about the microbiome of the built environment and how new research can inform your practice this week on IAQ Radio!
Microbiome’s best friend
Jordan Peccia, PhD, Associate Professor of Environmental Engineering at Yale University was today’s guest on IAQradio. As an undergrad Jordan was interested in aerospace and studied mechanical engineering. Wanted to work outdoors and he studied environmental engineering. While spending most of his time in the lab; he is excited about integrating microbiology with engineering to study important contemporary environmental problems.
Nuggets mined from today’s episode:
Dr. Peccia knows alot about waste water. There are 2 types of wastewater sludge, Class A and Class B. Class A is higher quality fertilizer in which the pathogens have been inactivated and presumed not to contain pathogens. According to the U.S. EPA, class A sludge is suitable for sale and pubic distribution. Class A sludge is heat processed at 55°-58° C by thermophilic digestion or composting. Milorganite™ fertilizer manufactured by Milwaukee Sewerage is a popular brand of Class A. Class B is presumed to contain pathogens and must follow land application regulations to reduce human exposure.
There are 3 primary methods for quantifying and identifying microbes in buildings: culturing, microscopy and DNA sequencing. While currently not as quantitative as microscopy, DNA sequencing lists hundreds of thousands of microbes and is our best approach for describing the full microbial communities in a sample.
We owe much that we know about the microbiome of the built environment to the recent application of new DNA sequencing technology. DNA sequencing research has become less costly by orders of magnitude. DNA sequencing more accurately reflects resident microbial diversity. Big conclusions: occupants are the primary sources of bacteria, fungal sources are mostly external (outdoor air and what is tracked in).
Researchers are getting a better handle on managing the depth of information providing by DNA sequencing. The trick is assembling the information in meaningful form and making sense out of it. Software to efficiently analyze and interpret the data sets is the biggest challenge.
He predicts that eventually investigation of water damage will shift to DNA sequencing.
Most important lesson learned is the merging of the human and built microbiomes. We have shifted the focus away from only thinking about the bad microbes to also considering the beneficial ones.
Diversity of microbes protects us from asthma.
Next-generation DNA sequencing reveals that low fungal diversity in homes is associated with childhood asthma development. The “Hygiene Hypothesis”, the benefits of kids being exposed to farm animals and house pets.
While studying potential pesticide exposure (Researchers working on the CHAMACOS cohort at UC Berkeley (A. Bradman, N. Holland, K. Harley, and B. Eskenazi) gathered years of data on indoor humidity, breast feeding, dust and found that children living in microbial diverse homes were 5 times less likely to develop asthma.
Over 2,000 types of fungi have been found in house dust. At this point, it appears that dampness is associated with fungal diversity. The connection between asthma and any one specific microbe is not strong.
Findings from a study of Aspergillus fumigatus, cultured at different temperatures and using blood serum from allergic people found that lower temperatures produced more potent allergens.
The Sloan foundation is funding a study of microbial growth on HVAC cooling coils.
Cryptococcus is a huge genus. Not all Cryptococci are pathogenic. Cryptococcus that may pose an increased asthma risk are also presumed to contribute to fungal loads indoors.
Got geeky when he discussed Basidiomycota and Ascomycota.
Collaborated with William W. Nazaroff, PhD, Cal Berkeley on a study of indoor emissions in school classrooms in the US, Europe and China. Microbial communities were studied inside and outside of occupied and unoccupied classrooms. 98% of total airborne bacteria was from the floor and were re-suspended. Important finding was that cleaning may be more important than ventilation for reducing indoor fungal and bacterial exposures. Occupants are the source, emitting 10 million bacteria per hour.
Microbial diversity is an important factor in asthma development. Lactobacillus is an important beneficial microbe. Pets are an important mediator of microbial communities. Take home lesson: get a dog!
Water leaks and pets increase indoor microbial diversity while running air conditioning reduces indoor microbial diversity.
Inconsistencies exist in human health related to moisture and microbial ecology. Shares an interest with Richard Shaughnessy, PhD Univ. of Tulsa in quantifying and identifying everything in samples to build a framework which will predict poor health outcomes for occupants of water damaged buildings.
Sample and tracking technology allows researchers to determine who was there, by sampling: human gut and human urine, building data bases of source trackers which attribute percentages to the results.
We don’t know what normal microbial ecology of indoor environments is. A goal is to design, build and maintain buildings in a manner than contributes to colonization by beneficial microbes.
Evolution of living with animals, get a dog!
Today’s Music: The Invisible Universe of the human Microbiome (NPR) YouTube
Z-Man signing off
Trivia: Name the person who first suggested and coined the term microbiome.
Answer: Joshua Lederberg