Microbial monitoring has taken place in major units belonging to the Environmental Control and Life Support Systems (ECLSS) of the International Space Station (ISS). For at least a decade, multiple modules, including US and RU segments, were sampled. In the US ECLSS, water reclamation and air systems combine their microbial contents downstream where biofilm incidents have been recorded. Understanding the microbial contents of segments provides a longitudinal perspective on microbiome changes in the system that contribute to this issue. The US ECLSS has been consistently sampled, especially in the Potable Water Bus (PWB) where bacteria from upstream sources have been observed. Both the US and RU ECLSS present a case for harboring known waterborne bacteria.
Justiniano et al. (Sun,) studied this question.