Architect sneaks into ASM – all three days

Just kidding; I paid to get in, but this conference is not intended for a research architect/building scientist like me. This was my third ASM meeting, and now I know something approaching 1% of the jargon, so I was able to “mine” the sessions, especially the posters, for built-environment-relevant content. Under the surface of the talks and the posters, many of the presenters I spoke with actually know something of relevance and practical use.

So I would ask questions related to the built environment application or relevance, like, ‘At what temperature did you try to grow those things?’ Or ‘what was the substrate or the duration of the experiment?’

Of course this works better at the poster sessions than in the large symposium where most of the attendees would probably be asking themselves, “who let this guy in here?” (We won’t tell them it’s all due to the Sloan Foundation’s dramatic efforts to make microbial ecology something that is useful in the sciences applied to the built environment. My own interests are primarily the indoor environment.)

So when I asked Kenneth Flynn (U of New Hampshire) about his poster, “Population genomics of experimentally evolved pseudomonas biofilms provides insight into the molecular mechanisms of ecological specificity,” what were the temperatures at which he did his experiments, I learned that there are people doing lung cultures of Pseudomonas. This will be worth following up on in terms of what they know about the temp and RH of inhaled air.

I have been very interested in linking the indoor environmental conditions (e.g., temperature, relative humidity, pH of moisture on surfaces, ventilation, surface material composition, topography, and chemistry) with the abundance, evolution, and pathogenicity or toxicity of indoor microbial communities. The human skin microbiome is most likely (my hypothesis) affected by some or many of these indoor environmental characteristics. But what about the respiratory tract? (The second of the three most environmentally-exposed surfaces, the gut being the third, of course)? The peer-reviewed literature indicates that the upper respiratory tract is a perfect air conditioner. But the experiments I have read about are fairly short in duration, a matter of minutes. What if someone works or plays or walks outdoors in hot humid or cold dry climate conditions for several hours? How long can the air we inhale be conditioned to reasonably constant temps and RHs? Well, obviously, not for many hours on end, not at least without a significant toll on the individual’s ability to sustain this. So the “climate” in the lung may not be some idealized (37 C) body core temperature all the time.

Robert Parker (Michigan State University) “Role of the rgf Operon in biofilm formation in Group B Streptococcus” — I asked about his substrates and he told me that the biofilm grew better on glass than on PVC. I found that surprising but discussed with him the fact that nearly all surfaces in human-occupied indoor environments are coated with a thin film of human skin oils (squalene compounds), and water and, a large range of volatile and semi-volatile organic chemicals. So surfaces are not always so simple to understand, and our assumptions about them may mislead us. I also mentioned that PVC contains phthalate plasticizers that are known endocrine disruptors. There will typically be a layer of such chemicals at the surface of a plastic token.

If this stuff interests you, come back soon for more of the building science jewels I mined from ASM presenters at discussions of their posters: in the lineup, Legionella, bacteria counts in “natural” air on a university campus, and the development of pseudomonas-biofilm resistant surfaces through manipulation of the surface topography.