Breakdown of Vibrio cholerae biofilm architecture induced by antibiotics disrupts community barrier function

Bacterial cells in nature are frequently exposed to changes in their chemical environment(1,2). For such stimuli, the response mechanisms of isolated cells have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure(3–7), which may hold the key to understanding the structure and functions of the most common bacterial communities: biofilms. Here, by monitoring all individual cells in Vibrio cholerae biofilms during exposure to commonly administered antibiotics for cholera infections, we discovered that translational inhibitors cause strong effects on cell size and shape, as well as biofilm architectural properties. We identified that single-cell-level responses result from the metabolic consequences of protein synthesis inhibition, and that the community-level responses result from an interplay of matrix composition, matrix dissociation, and mechanical interactions between cells. We further discovered that the antibiotic-induced changes in biofilm architecture have substantial effects on biofilm population dynamics and community assembly, by enabling invasion of biofilms by bacteriophages and intruder cells of different species. These mechanistic causes and ecological consequences of biofilm exposure to antibiotics are an important step towards understanding collective bacterial responses to environmental changes, with implications for the effects of antimicrobial therapy on the ecological succession of biofilm communities.