Bacteria can adapt in response to stressful environments. In this study, Phan et al. identify an emergent phenotype that enables Escherichia coli to escape near-lethal concentrations of antibiotics. When exposed to minimum inhibitory concentrations of cephalexin — a non-genotoxic antibiotic that impairs septum formation in bacteria — E. coli transforms into long helical filaments. The authors recorded swimming filaments using a high-speed resonant confocal microscope. Filaments were either right-handed or left-handed in conformation, but motile filaments were always right-handed. The helical bacteria were slightly past the critical torsional buckling point and had a twist angle of 2π radians, regardless of length. These cells do not swim by ‘run and tumble’ as observed in non-stressed E. coli, but rather synchronously flip their spin and velocity, causing them to reverse direction. The authors suggest that this motility increases the diffusivity of filamentous bacteria, enabling cells to more readily escape stress.