Fig 1. Mechanisms of collateral sensitivity.

Schematic illustration of resistance (top left) and collateral sensitivity (top right) of a strain with resistance mechanism against antibiotic R. The resistant strain is indicated with a dashed line, and the susceptible wild-type strain with a solid line. Yellow shading indicates increased inhibitory activity of antibiotic A. The inhibitory effect of A that is generated upon binding of target structure T may be increased by several theoretical mechanisms (numbered 1–4). Bold arrows indicate increased functions. Broken arrows indicate reduced functions.