Pathophysiology
Clinical meaning
Antibiotic stewardship programs (ASPs) are systematic approaches to optimize antimicrobial use, improving patient outcomes while reducing resistance selection pressure, C. difficile infections, and healthcare costs. Core strategies include: (1) Empiric-to-targeted de-escalation โ start broad-spectrum empiric therapy for serious infections, then narrow to the most targeted agent once culture and sensitivity results return. (2) Prospective audit and feedback โ ASP pharmacists and infectious disease physicians review antibiotic orders and provide real-time recommendations to prescribers. (3) Formulary restriction and preauthorization โ restricting certain broad-spectrum agents (carbapenems, fluoroquinolones) to require ASP approval. (4) Dose optimization โ using pharmacokinetic/pharmacodynamic (PK/PD) principles to maximize efficacy while minimizing resistance. Time-dependent antibiotics (beta-lactams): efficacy depends on time above MIC โ extended/continuous infusions improve outcomes. Concentration-dependent antibiotics (aminoglycosides, fluoroquinolones): efficacy depends on peak/MIC ratio โ high doses with extended intervals optimize killing. (5) Duration optimization โ shorter courses are often equivalent (e.g., 5-7 days for uncomplicated pneumonia, 3 days for uncomplicated UTI, procalcitonin-guided discontinuation in sepsis). (6) IV-to-oral switch โ transition to oral when patients are clinically improving and can tolerate oral medications (same drug or equivalent bioavailability...