Mankind moved from 'Ecosystem Nature' into 'Sealed Building Biotopes'

摘要

Mankind moved from "Ecosystem Nature" into "Sealed Building Biotopes" The consequences call for a new hygiene concept with updated microbial perspectives In the very short timeframe of the last two hundred years, industrial revolutions shifted our living and working spaces more and more into buildings, which became increasingly airtight in the last fifty years. Spending more than ninety percent of our lifetime in sealed rooms, often mechanically ventilated with filtered air, limited our interactions with the diversified microbiomes of nature. Our building habitats have become sealed biotopes. For hygienic reasons, natural and locally available mainly porous materials for construction, interior finish and accessories have increasingly been replaced by fabricated, easy to clean, nonporous materials. These materials lack any water storage capacity and are either wet (if undesired condensation occurs) or dry, independent of the relative humidity in the surrounding air. From the perspective of surface attached bacteria and mould, this results in a permanent, year round stress by deprivation of water and nutrients. This stress scenario, intended for hygienic reasons in order to efficiently prevent any proliferation of bacteria and mould turned out to have dangerous side effects on human beings. The provoked stress adaptations (morphologic, metabolic and genetic) of bacteria result in multi-resistance, including antibiotic resistance. This issue is becoming particularly evident in hospital environments where we had to recognize that the multi-resistant gram positive and negative bacteria causing hospital associated infections share the common feature of resistance to water and nutrient deprivation. Dryness and cleanliness as hygienic concepts need to be reconsidered in the light of updated knowledge of microbial stress reactions that combines culture based methods with stress testing and genome sequencing.