It turns out that cities have microbial signatures that make them unique. Scientists have found that communities of microbes within a city don't vary much, but between cities, they do.
In this latest study, the researchers sampled microbes from nine offices in three North American cities. More specifically, they monitored these offices for over a one-year period in Flagstaff, San Diego and Toronto. In each office, they installed three sampling plates, with one plate each on the floor, ceiling and wall.
The researchers also installed sensors in the offices that allowed them to monitor parameters of the environment, such as relative humidity on the surfaces of the swatches, available light, occupancy and temperature. In all, the researchers collected samples during four six-week sampling periods.
"We suspect that in the absence of extreme conditions like flooding, microbes may be passively accumulating on surfaces in the built environment rather than undergoing an active process," said J. Gregory Caporaso, one of the researchers involved in the study from the Northern Arizona University in Flagstaff. "As we continue to expand our understanding of the microbiology of the built environment, possibly including routine monitoring of microbial communities to track changes that may impact human health, our results will help inform future research efforts."
The researchers found that floor samples, regardless of material, contained more microbes than wall or ceiling surfaces. Not only that, but the Flagstaff offices had a richer microbial community than the ones in San Diego or Toronto. Across the nine offices, the researchers found, in particular, that human skin bacterial communities were what characterized the microbial communities.
What was interesting, though, was that offices didn't differ too much within cities. Between cities, though, they differed quite a bit.
"This was especially interesting because even within each city, the offices we studied differed from each other in terms of size, usage patterns and ventilation systems, suggesting that geography is more important than any of these features in driving the bacterial community composition of the offices with the ranges that we studied," Caporaso said.
The results reveal a bit more about the bacterial communities located in office spaces. This, in turn, may allow researchers to identify what location bacteria came from.
The findings were recently published in the journal mSystems.
