Bacteria poison and eat their neighbors

Abstract

Bacteria have evolved numerous ways to kill nearby cells, often by secreting diffusible toxins, secondary metabolite antibiotics, or toxic metabolic by-products (1). Many bacteria also possess mechanisms for direct, contact-dependent killing. For example, the type VI secretion system (T6SS) extends a molecular needle into cells to deposit toxins (2, 3). Bacteria bearing such poison needles carry antidotes to their own toxins to avoid killing themselves or other cells of their type. The T6SS provides an advantage by removing competitor cells that might otherwise consume the same resources (4, 5). On page 1214 of this issue, Stubbusch et al. (6) report that T6SS-bearing cells can grow and replicate using the released contents of neighboring cells that they kill. This suggests that the T6SS—and potentially other mechanisms of bacterial antagonism—could be used not only to create space by eliminating competitors but also as a predatory nutrientscavenging mechanism.