Pathophysiology
Clinical meaning
Antibiotic resistance develops through genetic mutations or horizontal gene transfer (plasmids, transposons, transformation) that allow bacteria to survive antibiotic exposure. Resistance mechanisms include: enzymatic inactivation (beta-lactamases destroying penicillins), altered target sites (PBP mutations in MRSA), efflux pumps (tetracycline resistance), reduced permeability (porin channel mutations in gram-negatives), and biofilm formation. Inappropriate antibiotic use (unnecessary prescribing, subtherapeutic dosing, incomplete courses) accelerates selection of resistant organisms. The nurse contributes to stewardship by administering antibiotics at the correct time, reporting adverse effects, and educating patients on adherence.