FIGURE 5.

Polymyxin Resistance Mechanism. This illustration showcases the various mechanisms by which bacteria develop resistance to polymyxin. Central to this resistance is the structure of Lipopolysaccharide (LPS) present in the bacterial cell, as highlighted in figure. (A) The mcr gene on bacterial plasmids facilitates the primary resistance mechanism, as depicted by the label mcr in the image. Furthermore, resistance can arise from covalent modifications to Lipid A (B) or structural alterations in the LPS (E). The efficacy of polymyxin is further diminished by the reduced charge on LPS (D), especially when it interacts with cations such as Mg²⁺. (C) The growth medium conditions in which bacteria reside can also influence their susceptibility to polymyxin.