Antimicrobial Stewardship and Infection Prevention
Core concepts
Stewardship aims to improve outcomes while minimizing harm: appropriate indication, agent, dose, duration, and de-escalation. Know the core interventions (prospective audit and feedback, formulary restriction/preauthorization, rapid diagnostics, IV-to-PO conversion, allergy assessment, and syndrome-specific pathways). Understand metrics: days of therapy (DOT) per 1,000 patient-days, defined daily dose (DDD), and antibiotic time-outs. Recognize the drivers of resistance: selective pressure, inadequate dosing, and unnecessary broad-spectrum use. Infection prevention essentials include hand hygiene, contact precautions for multidrug-resistant organisms (MDROs), isolation for C. difficile, central line-associated bloodstream infection (CLABSI) bundles, catheter-associated urinary tract infection (CAUTI) prevention, and surgical antimicrobial prophylaxis timing. Know the difference between colonization pressure and cross-transmission and the role of environmental cleaning.
Traps
- Equating stewardship with restriction only; audit-and-feedback and education are core.
- Using length of therapy rather than DOT when comparing across units.
- Forgetting that C. difficile requires contact precautions plus soap-and-water handwashing (alcohol does not kill spores).
- Assuming a positive culture means treatment is needed.
Rule of thumb
Every antimicrobial order should answer: Does the patient need it? Is the spectrum right? Is the dose right? Can it be narrowed or stopped?
Worked example: A patient on broad-spectrum therapy for 72 hours with negative cultures and resolving symptoms: de-escalate to the narrowest effective agent or discontinue, documenting the rationale.