Kill switches for engineered microbes gone rogue

Stable autonomous kill switches ensure biocontainment of living microbes designed as devices for medicine or the environment. New research outlines two new types of kill switches that address these challenges. The new kill switches are self-sufficient and highly stable in bacterial populations that evolve, and they last over many generations. They can ensure that only bacteria with intact synthetic gene circuits survive, or confine bacteria to a target environment at 37°C (body temperature) while inducing them to die at lower temperatures, as demonstrated during bacterial exit from a mouse intestinal tract.