Predicting how varying moisture conditions impact the microbiome of dust collected from the International Space Station (ISS)

The International Space Station is a specialized closed environment that contains own unique indoor microbiome. Elevated moisture such as from a temporary ventilation system malfunction may lead to unintended microbial growth indoors, which is associated with negative health outcomes and degradation of essential built environment materials.

We need to develop a predictive approach for modeling microbial growth to understand when it may occur in these critical indoor spaces. Here we demonstrate that exposure to even fluctuating elevated relative humidity above 80% can lead to rapid microbial growth and community composition changes in dust from spacecraft. We were able to model fungal growth in space station dust using the time-of-wetness framework with activation and deactivation limited growth occurring at 85% and 100% relative humidity conditions, respectively.