The specific biochemical interaction through which an antimicrobial produces its pharmacological effect.

For antibiotics, the most common mechanisms of action are:

  • Inhibition of cell wall synthesis
  • Inhibition of protein synthesis
  • Disruption of cell membranes
  • Inhibition of DNA replication or transcription
  • Inhibition of bacterial metabolism

For compounds identified in phenotypic screens, mechanisms of action may not be immediately obvious. Further studies are required to understand how they achieve their antibacterial effects.

Determining mechanism of action is important because it suggests what modifications could be made to a compound to improve its activity and specificity.

In addition, antibiotics used as combinations should ideally have different mechanisms of actions, to make it harder for bacteria to develop resistance to treatment.