Alteration of target protein
Structural change — alteration of DNA gyrase
Overproduction — increased amount of target enzyme
Reduced access to target
Reduction in cell wall permeability to ABX — imipenem resistance
Alteration in PBP — MRSA
Actively pumping out ABX from cell — tetracycline resistance
Enzymatic inactivation of antibiotic
… beta lactam / aminoglycoside resistance