Antimicrobial Stewardship

Antimicrobial stewardship (AMS) is a coordinated set of interventions designed to optimize antimicrobial use, improve patient outcomes, reduce adverse events (including Clostridioides difficile infection), and slow the emergence of antimicrobial resistance. The CDC and IDSA identify core elements of hospital AMS programs: leadership commitment, accountability (physician or pharmacist leader), drug expertise (clinical pharmacist), action (implementing interventions), tracking (monitoring prescribing and resistance patterns), reporting (providing feedback to prescribers), and education. Two primary AMS strategies are prospective audit with feedback (reviewing antimicrobial orders after initiation and providing recommendations to the prescriber) and formulary restriction with preauthorization (requiring approval before certain antimicrobials can be dispensed). De-escalation involves narrowing antibiotic spectrum once culture and susceptibility data are available, which reduces selection pressure for resistant organisms without compromising outcomes. IV-to-PO conversion criteria include clinical improvement, functioning GI tract, ability to tolerate oral medications, and availability of a bioequivalent oral formulation. Procalcitonin-guided antibiotic discontinuation has been validated in respiratory infections and sepsis, with levels below 0.25 ng/mL supporting safe discontinuation. The institutional antibiogram aggregates local susceptibility data to guide empiric therapy and is updated annually.