Core Principles of Antimicrobial Stewardship

The core principles of antimicrobial stewardship describe what it means to use an antimicrobial appropriately and which interventions most reliably move prescribing toward that ideal. They centre on choosing the right agent, dose, duration, and route for the clinical situation, and on the two strategies that professional guidelines identify as foundational: prospective audit with feedback to prescribers, and formulary restriction with preauthorization.

Definition

The core principles of antimicrobial stewardship are the foundational rules and interventions for promoting appropriate antimicrobial use, summarised as selecting the optimal drug, dose, duration, and route, and operationalised chiefly through prospective audit and feedback and through formulary restriction with preauthorization.

Scope

This topic covers the definition of appropriate antimicrobial use, the rationale that ties prescribing behaviour to resistance, and the principal intervention types (restrictive and persuasive) recognised by stewardship guidelines. It is a methodological and educational topic about how prescribing is improved at the population and institutional level, not a guide to choosing therapy for an individual patient.

Core questions

• What does 'appropriate' antimicrobial use mean in practice?
• Which intervention strategies do guidelines treat as core?
• How do restrictive and persuasive interventions differ in their effects?
• What does the evidence say about the benefits and trade-offs of each strategy?

Key concepts

• Right agent, dose, duration, route
• Prospective audit and feedback
• Formulary restriction and preauthorization
• Restrictive versus persuasive interventions
• Guideline concordance
• Selective pressure
• Unintended consequences of prescribing

Mechanisms

Appropriate use is framed around four prescribing decisions - which agent, what dose, how long, and by what route - each of which affects both patient outcome and the selective pressure exerted on microbial populations. Guidelines organise stewardship interventions into two core categories. Prospective audit with intervention and feedback reviews active prescriptions and returns recommendations to the treating team, a persuasive approach that preserves prescriber autonomy. Formulary restriction with preauthorization requires approval before designated agents are dispensed, a restrictive approach that constrains choice at the point of prescribing. Both are supported by supplementary elements such as guideline development, education, and the use of microbiology and pharmacy data.

Clinical relevance

These principles underpin how hospitals and health systems structure efforts to improve prescribing, and familiarity with them supports critical reading of stewardship studies. Systematic reviews report that interventions built on these core strategies increase guideline-concordant prescribing and can reduce unnecessary therapy without evidence of harm. The topic describes how prescribing quality is studied and improved at a system level and is not a basis for individual treatment decisions.

Evidence & guidelines

The 2007 and 2016 IDSA/SHEA guidelines define the core strategies and supplementary elements of stewardship. The Cochrane review by Davey and colleagues (2017) and the meta-analysis by Schuts and colleagues (2016) summarise the comparative effectiveness of the principal intervention types.

History

The articulation of audit-and-feedback and formulary restriction as the two core stewardship strategies dates to the 2007 IDSA/SHEA guideline, which consolidated earlier, more scattered hospital experience into a coherent framework. The 2016 update reaffirmed these as foundational while expanding the evidence base for a wider menu of interventions.

Debates

Restrictive versus persuasive interventions

Restrictive approaches change prescribing faster but may have shorter-lived effects and can displace prescribing to non-restricted agents, whereas persuasive approaches act more gradually but sustain prescriber engagement; reviews support both, and the balance is debated.

Seminal works

• dellit-2007
• barlam-2016

Frequently asked questions

What are the two core strategies of antimicrobial stewardship?

Professional guidelines identify prospective audit with feedback to prescribers and formulary restriction with preauthorization as the two core, evidence-supported strategies, supported by guideline development, education, and use of microbiology data.

Does appropriate use always mean using a narrower or shorter course?

Not necessarily. Appropriateness means matching the agent, dose, duration, and route to the clinical situation, which can mean prompt effective therapy in one case and narrowing or stopping it in another.