Characterizing biofilm interactions betweenRalstonia insidiosaandChryseobacterium gleum

AbstractRalstonia insidiosaandChryseobacterium gleumare bacterial species commonly found in potable water systems and these two species contribute to the robustness of biofilm formation in a model six-species community from the International Space Station (ISS) potable water system. Here, we set about characterizing the interaction between these two ISS-derived strains and examining the extent to which this interaction extends to other strains and species in these two genera. The enhanced biofilm formation between the ISS strains ofR. insidiosaandC. gleumis robust to starting inoculum and temperature, occurs in some but not all tested growth media, and evidence does not support a soluble mediator or co-aggregation mechanism. These findings shed light on the ISSR. insidiosaandC. gleuminteraction, though such enhancement is not common between these species based on our examination of otherR. insidiosaandC. gleumstrains, as well as other species of Ralstonia and Chryseobacterium. Thus, while the findings presented here increase our understanding of the ISS potable water model system, not all our findings are broadly extrapolatable to strains found outside of the ISS.ImportanceBiofilms present in drinking water systems and terminal fixtures are important for human health, pipe corrosion, and water taste. Here we examine the enhanced biofilm of cu-cultures for two very common bacteria from potable water systems,Ralstonia insidiosaandChryseobacterium gleum. While strains originally isolated on the International Space Station show enhanced dual-species biofilm formation, terrestrial strains do not show the same interaction properties. This study contributes to our understanding of these two species in both dual and mono-culture biofilm formation.