The document summarizes the discussions and recommendations from a symposium on microbiomes in built environments. [1] Key areas discussed were the interaction between microorganisms and building materials, the need for longitudinal studies to understand changes over time, and developing reference genomes of cultured isolates. [2] Other recommendations included establishing shared buildings for controlled research, studying the effects of human and non-human occupants, climate change, metadata standards, and citizen science approaches. [3] The overall goal is to better understand and control indoor microbial communities to promote healthy buildings.

1. Microbiomes of Built Environments:
2011 Symposium Highlights & Workgroup Recommendations
Indoor Air 2011: Symposium on June 8th / 9th, 2011 (Austin, Texas)– 9,
Richard L. Corsi1, Hal Levin2, Jonathan Eisen3, and Kerry A. Kinney1
1. The University of Texas at Austin
2. microBEnet and Building Ecology Research Group
3. microBEnet - University of California, Davis
Healthy Buildings 2012 - Brisbane, Australia

2. Symposium Overview
Sponsored by the Alfred P. Sloan Foundation
DAY 1
• Keynote: J. Craig Venter
• 15 podium speakers
Day 2
• State of Knowledge: Aino Nevalainen
• New Tools and Opportunities: Jonathan Eisen
• Need to think big: Jesse Ausubel
• Workshop

3. Workgroup Recommendations

4. 1. Microorganisms & Building Materials
• Far more attention needed - interaction with materials
• Material properties (composition, porosity, water capacity)
• Surface temperature and humidity
• Microbial communities on damp materials
• Fungi, bacteria (100% of materials)
• Amoebae (20% of materials)
• Aged wood, gyp board, mineral wool
• Synergistic effects?
• Yli-Pirilä et al. (2004 & 2008)

5. 2. Longitudinal Studies in Buildings
• How do microbial communities change over time and why?
• Changes (or controlled perturbations) in:
• Outdoor environmental conditions
• Indoor environmental conditions
• Building materials/furnishings
• Operations (HVAC, etc.)
• Maintenance (cleaning, etc.)
• Occupant loads / activities
U of Chicago – Center for Health Statistics http://healthstats.org/

6. 3. Reference Genomes of Cultured Isolates
• Sequencing of “reference genomes” from cultured isolates
• Different types of microorganisms removed from buildings
• Valuable community resource
• Predicting functions of importance
• Interpretation of PCR and metagenomic
sequence data

7. 4. Functioning of Microorganisms
• Cataloging is good, but not sufficient in and of itself
• Need to know what the microorganisms are doing
“You can observe a lot just by watching.” – Yogi Berra

8. 5. Shared Buildings
• Several around the world are needed (different climate zones)
• Many benefits:
• Controlled and systematic research efforts
• International & interdisciplinary collaborations
• Compare sampling methods between teams
• Deeper exploration: environmental, building, occupant factors
• Facilitate proposal development

9. 6. Human Occupants
• Humans are important sources of bacteria (Täubel et al., 2009)
• Mattresses: 69-88% of bacteria of human origin
• Floor dust: 45-55% of bacteria of human origin
• Spatial activity patterns & resuspension (e.g., Hospodsky et al., 2012)
• Research needed on behavior & activity effects
• Cleaning practices (how and how frequently, etc.)
• Surface cleaning, vacuum cleaning, etc.
• Microbial community variations / redistribution
• Occupant profiles
• Age, gender, culture, socioeconomics
• Psychology/personality

10. 7. Non-Human Occupants
• Pets can be important sources of bacteria
• Canine contributions (Johansson et al., 2011)
• 2+ dogs: Strong predictor of streptomycetes & endotoxins
• Variations: outdoor/indoor pets versus indoor pets?
• Diet effects?
• Age effects?
• Cleaning effects?
Chloe Corsi
outdoor/indoor Australian cattle dog

11. 8. Effects of Climate Change
• How do indoor microbiomes change as climate changes?
Griffith, Australia 2002
• Direct impacts of climate change
• Heat waves, dust storms
• more intense rainfall, etc.
• Mitigation and adaptation effects on buildings
• Weatherization / tight envelope design
• Rapid implementation of green building materials
• New insulations, etc.

12. 9. Metadata Consensus
• Standardized checklist(s) for researchers
• Sampling methodologies
• Environmental conditions
50 oC
(what, when, where)
13 oC
• Building design and layout
23 oC 35 oC
• Building ventilation methods
• HVAC system / components 18-32 oC
18 oC
• Building materials 40
Attic
• Building operation parameters 35
Indoor
30
• Building maintenance (cleaning, etc.)
Outdoor
Temperature (oC)
25
• Previous water challenges 20
Supply Vent
• Flexibility – One size does not fit all!
15
Difference between supply & attic ≈ 0 - 20 oC (68 oF)
Maximum difference can exceed 40 oC (104 oF)
10

13. 10. Microbial Communities and Chemicals
• Changes in surface chemistry via pH changes
• CO2, NOx, cleaners (HOCl, etc.)
• Chemicals deposited on surfaces
• Chemical transformations of surfaces

14. 11. Citizen (building/microbial) Science
• Get general population excited and involved
• Sample collection in homes, schools, etc.
• Possibility of HVAC filters as integrated samplers
• Centralized analysis sites for “citizen samples”
• Metadata via questionnaire

15. 12. Routine Surveillance Technologies
• Development & verification of new technologies
• Routine surveillance of indoor microorganisms
• If low cost – facilitate citizen science

16. Grand Challenge
Design, operate, & maintain microbially-balanced, healthy buildings
1. How do we improve characterization/testing of existing and
new building materials & their influence on microbes
• Key properties & changes with time?
• Test protocols?
• Microbial communities?
2. How do we effectively build spatial and temporal variability
into field studies?
• Microbial sampling
• Building and environmental condition sampling