What is the importance of antimicrobial stewardship in promoting the appropriate use of antimicrobial agents?

Antimicrobial Stewardship: A Critical Framework for Optimizing Antibiotic Use

Antimicrobial stewardship is a systematic approach to optimizing antibiotic prescribing that improves patient outcomes, reduces antimicrobial resistance, decreases adverse events including Clostridium difficile infections, and lowers healthcare costs through coordinated interventions focused on the "5 Ds": right diagnosis, drug, dose, duration, and de-escalation. 1, 2

Core Objectives and Rationale

Antimicrobial stewardship programs (ASPs) exist because inappropriate antibiotic use—occurring in 25-63% of prescriptions—is the single most important preventable cause of antimicrobial resistance in both hospital and community settings. 1 The primary goals are to:

• Optimize clinical outcomes while minimizing unintended consequences including adverse events, selection of pathogenic organisms, and emergence of resistance 1, 2
• Reduce antimicrobial resistance and prolong the lifespan of existing antibiotics 1
• Decrease healthcare-associated infections, particularly C. difficile infections 2, 3
• Lower healthcare costs through reduced drug expenditures and improved resource utilization 1, 2
• Improve patient safety by reducing the estimated 142,500 annual ED visits for antibiotic-related adverse events, 80% of which are allergic reactions 1

Essential Program Components

Leadership Structure

Every ASP requires leadership by an infectious disease physician with stewardship training, partnered with a clinical pharmacist with infectious disease expertise as the core team. 2, 3 This multidisciplinary foundation is non-negotiable for program success. 4

Primary Intervention Strategies

The two evidence-based primary strategies are:

1. Formulary Restriction and Preauthorization

• Requires real-time approval before administering restricted broad-spectrum antibiotics 2, 3
• Controls use at the point of ordering to prevent inappropriate initiation 3, 5
• Optimizes empiric antibiotic choices based on local resistance patterns 3
• Limitation: May delay therapy in urgent situations and can create prescriber frustration 3

2. Prospective Audit and Feedback

• Reviews antibiotic prescriptions 24-48 hours after initiation with recommendations to optimize therapy 2, 3
• Maintains prescriber autonomy while providing educational benefit 3
• Has demonstrated 22% reductions in broad-spectrum antibiotic use over 7-year periods 3
• Decreased C. difficile infections without adversely affecting mortality 3

Both strategies have proven effective at achieving stewardship goals, and the most successful programs employ both approaches simultaneously. 2, 5

Supplemental Strategies

Beyond the two primary interventions, effective ASPs incorporate:

• Facility-specific clinical practice guidelines for common infections based on local epidemiology and resistance patterns 3, 4
• De-escalation protocols to narrow antibiotic spectrum once culture results are available 4, 5
• IV-to-oral conversion programs to optimize route of administration 4
• Dose optimization to ensure adequate drug exposure while minimizing toxicity 4, 6
• Clinical decision support systems integrated into electronic health records 1
• Rapid diagnostic testing to guide appropriate antibiotic selection 1

Critical Measurement and Monitoring

Programs must measure antibiotic use using Days of Therapy (DOTs) per 1,000 patient-days as the preferred metric, stratified by individual antibiotic agent. 7 This approach is superior to Defined Daily Doses because DOTs are unaffected by dose adjustments and can be applied to both adult and pediatric populations. 7

Additional essential metrics include:

• Appropriateness of therapy through guideline compliance assessment 7
• Tracking the "5 Ds": diagnosis accuracy, drug selection, dose optimization, duration appropriateness, and de-escalation timing 1, 7
• Antimicrobial resistance patterns and C. difficile infection rates (recognizing these are influenced by multiple factors beyond antibiotic use alone) 7

Application in Specific Settings

Emergency Department Considerations

The ED represents a particularly critical setting because it sits at the interface of inpatient and outpatient care, and the initial antibiotic choice made in the ED significantly influences what therapy continues during hospitalization. 1

Key ED-specific challenges include:

• High patient turnover and need for rapid decision-making without consultation 1
• Overcrowding and operational efficiency pressures 1
• Medical liability concerns leading to antibiotic overuse 1
• Perceived patient satisfaction requirements (though studies show provision of antibiotics increases satisfaction for respiratory infections) 1

ED stewardship interventions should focus on:

• Watchful waiting protocols for specific infectious syndromes with structured follow-up 1
• Blood culture stewardship for common infectious syndromes (excluding sepsis/septic shock) 1
• Biomarkers and rapid diagnostic tests to guide antibiotic initiation 1
• Integration of ED pharmacists into stewardship efforts 1

Outpatient Stewardship

The CDC recommends outpatient ASPs include: (1) commitment to optimizing prescribing and patient safety, (2) implementation of stewardship policies, (3) tracking prescribing practices through clinician feedback, and (4) access to educational resources. 1

A critical principle: Limiting systemic antibiotics when possible reduces antibiotic resistance and complications. 1 In 2021, dermatologists prescribed more oral antibiotics per clinician than all other specialties, with the majority for acne treatment—highlighting the need for specialty-specific stewardship. 1

Principles of Responsible Antimicrobial Use

Use antibiotics only when infections are proven or strongly suspected to be caused by susceptible bacteria. 8, 9 When culture and susceptibility information are available, they must guide therapy selection. 8, 9 In the absence of such data, local epidemiology and susceptibility patterns should inform empiric selection. 8, 9

For H. pylori and other curable infections, optimized therapy is defined as reliably achieving cure rates ≥95%, with unacceptable therapies being those failing to achieve at least 90% cure rates. 1 This contrasts with the traditional "better than" comparison approach and represents a fundamental shift toward antimicrobial stewardship principles. 1

Common Pitfalls and How to Avoid Them

Pitfall 1: Relying on education alone Education produces non-sustainable improvements in prescribing. 3 Programs must integrate stewardship principles into daily clinical decision-making through systematic interventions, not just didactic teaching. 3

Pitfall 2: Ignoring local resistance patterns National guidelines cannot substitute for facility-specific antibiograms and local resistance data. 3 Clinicians must learn their institution's specific patterns during each rotation. 3

Pitfall 3: Inadequate administrative support Obtaining adequate administrative support and compensation for team members is a major barrier. 4 Programs require dedicated resources and cannot function as unfunded mandates.

Pitfall 4: Physician resistance due to perceived loss of autonomy Gaining physician acceptance is challenging when prescribers perceive loss of clinical decision-making autonomy. 4 Prospective audit and feedback maintains autonomy better than preauthorization and provides educational benefit. 3

Pitfall 5: Using inappropriate metrics C. difficile infection rates and resistance patterns have significant limitations as primary stewardship metrics because they are affected by infection control practices and multiple confounding factors. 7 DOTs per 1,000 patient-days remains the gold standard measurement. 7

Evidence-Based Outcomes

Well-implemented ASPs have demonstrated:

• 22% reduction in broad-spectrum antibiotic use over 7-year periods 3
• Decreased C. difficile infections without adversely affecting mortality 3
• Reduced rates of resistant gram-negative bacilli and vancomycin-resistant enterococci 10
• Improved cure rates and decreased failure rates while reducing healthcare costs 10
• Lower rates of antibiotic-associated complications including inflammatory bowel disease, pharyngitis, and Candida vulvovaginitis 1

Patient Communication Strategy

When antibiotics are not indicated for viral infections, explain to patients why antibiotics are unnecessary and discuss the personal risks of antibiotic use (allergic reactions, C. difficile infection, resistance development). 3 This approach manages expectations and reduces demand for inappropriate prescriptions more effectively than simply refusing to prescribe. 3