What is antibiotic resistance and why is it a growing concern?

Antibiotic resistance occurs when bacteria evolve mechanisms to survive exposure to antibiotics that previously killed them. Common mechanisms include producing enzymes like beta-lactamase that destroy the antibiotic, altering the drug target site, reducing cell wall permeability, and developing efflux pumps that expel the drug. Resistance is accelerated by overprescribing, incomplete treatment courses, agricultural antibiotic use, and poor infection control.