surface motility and invasion into competing communities enhances interspecies antagonism.

Chronic polymicrobial infections involving and are prevalent, difficult to eradicate, and associated with poor health outcomes. Therefore, understanding interactions between these pathogens is important to inform improved treatment development. We previously demonstrated that is attracted to using type IV pili-mediated chemotaxis, but the impact of attraction on growth and physiology remained unknown. Using live single-cell confocal imaging to visualize microcolony structure, spatial organization, and survival of during coculture, we found that interspecies chemotaxis provides a competitive advantage by promoting invasion into and disruption of microcolonies. This behavior renders susceptible to antimicrobials. Conversely, in the absence of type IV pilus motility, cells exhibit reduced invasion of colonies. Instead, builds a cellular barrier adjacent to and secretes diffusible, bacteriostatic antimicrobials like 2-heptyl-4-hydroxyquinoline-oxide (HQNO) into the colonies. reduced invasion leads to the formation of denser and thicker colonies with significantly increased HQNO-mediated lactic acid fermentation, a physiological change that could complicate the effective treatment of infections. Finally, we show that motility modifications of spatial structure enhance competition against . Overall, these studies build on our understanding of how type IV pili-mediated interspecies chemotaxis mediates polymicrobial interactions, highlighting the importance of spatial positioning in mixed-species communities.