Host environment shapes S. aureus social behavior by promoting plastic interaction of planktonic and sessile multicellular communities

Bacteria can develop different social lifestyles to adapt to environmental changes and resist attacking agents like antibiotics. Weshow that in physiological media, rich in polymers and others bridging molecules, planktonic biofilm-like aggregates and sessile biofilm lifestyles are two co-existing and interacting phases of the same environment-adaptive developmental process. Subtle changes in the physicochemical properties of growing medium have profound effects on the kinetics and spatial organization of planktonic aggregation, sessile biofilm formation, and the transition from the former to the latter. Sensitivity of bacterial development to other environmental conditions like oxygen availability and agitation also depends drastically on the used growth medium. Crucially, our results highlight the inadequacy of commonly used lab media for both biological and clinical studies of bacterial development.