More than 30,000 bacteria are sleeping in offices

Air conditioning systems have a lasting influence on the bacterial flora indoors

03/02/2014

In interiors and offices, there are over 30,000 different types of bacteria. The architecture of the building and the intensity of its use have a significant influence on the bacterial flora that can be found, Canadian researchers report in the journal „PLOS One“. The researchers led by Steven Kembel from the Université du Québec à Montréal, in a recent study examined the „Bacteria communities in the dust of 155 rooms in Lillis Hall, a four-story classroom and office building on the campus of the University of Oregon.“

The sequencing of the detected bacterial species has shown that architectural design features, room type, room layout, human use and ventilation source are closely related to the detectable bacterial communities. For example, the toilet rooms had completely different microbial communities than most of the other rooms were. The rooms with intensive use by many people were much more burdened with bacteria, as little-used, remote spaces. In the offices, however, the source of ventilation air has shown the greatest impact on the structure of the bacterial community, Kembel and colleagues report. If air conditioning was used, the bacterium Deinococcus had been surprisingly dominant.

About the architecture affect the bacterial flora?
In their investigation of the dust samples, the scientists have mainly detected three bacterial strains: Proteobacteria, Firmicutes and Deinococcus. While the former are more related to human use, increased settlement of Deinococcus is directly related to the use of air conditioning, Kembel and colleagues report. This may be due to the resistance of these bacteria to temperature changes, dehydration and UV light, which favor selection of bacterial strains. The scientists come to the conclusion that the architectural or interior design of the buildings could directly influence the settlement of the bacteria in order to create a healthy environment as possible. The same applies to the effects of human occupancy and patterns of use, which in turn are closely related to the bacterial flora. (Fp)

Image: Benjamin Matzmorr / pixelio.d