Antimicrobial Stewardship

  • Antimicrobial stewardship refers to a set of coordinated strategies to improve the use of antimicrobial medications with the goal of enhancing patient health outcomes, reducing resistance to antibiotics, and decreasing unnecessary costs.


  • Maximum antimicrobial benefit
  • Avoid harm from adverse reactions and drug allergies
  • Improve patient outcomes
  • Decrease antimicrobial resistance
  • Decrease healthcare costs
  • Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance.
  • With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. 

Antimicrobial resistance (AMR):

  • AMR threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses, and fungi
  • an increasingly serious threat to global public health that requires action across all government sectors and society.
  • Without effective antibiotics, the success of major surgery and cancer chemotherapy would be compromised.
  • The cost of health care for patients with resistant infections is higher than care for patients with non-resistant infections due to longer duration of illness, additional tests and use of more expensive drugs.
  • In 2016, 4,90,000 people developed multi-drug resistant TB globally, and drug resistance is starting to complicate the fight against HIV and malaria, as well.
  • Therefore, these programs are needed to help clinicians to improve the quality of patient care and improve patient safety through increased infection cure rates, reduced treatment failures, and increased frequency of correct prescribing for therapy and prophylaxis.

What constitutes an Antibiotic Stewardship Program (ASP)?

  • usually involves pharmacists, physicians, and other healthcare providers.
  • The Infectious Diseases Society of America/Society for Healthcare Epidemiology of America (IDSA/SHEA) Guidelines for Antimicrobial Stewardship were published in 2007.
  • According to these guidelines, an institutional antimicrobial stewardship program should include an
    • infectious disease trained physician and
    • an infectious disease trained pharmacist as core members, with the inclusion of a
    • clinical microbiologist,
    • an infection control practitioner,
    • an information systems expert and
    • a hospital epidemiologist considered optimal.

The role of individuals in ASP:

1. Infectious Disease Physician

  • Helps in the design, implementation and proper functioning of the program.
  • ensures that therapeutic guidelines, antimicrobial restriction policies, or other measures are based on the best evidence and practice and will not put patients at risk.

2. Clinical and Hospital pharmacists

  • act as the effector arms for antimicrobial stewardship programs because of their role in processing medication orders and their familiarity with the hospital formulary.
  • Due to this role, they may note when restricted antimicrobials are ordered and notify the prescriber that authorization is required.
  • They may also flag orders for review by infectious disease specialists, in addition to their usual role in assuring proper dosing and safety.
  • However, the broad responsibilities of these pharmacists generally do not allow adequate time for a comprehensive review of antimicrobial therapy.
  • In addition, these pharmacists may not have adequate training in infectious diseases to feel comfortable providing recommendations for complex cases.
  • Thus, having a clinical pharmacist with specialized training in infectious diseases dedicated full or part-time to the administration of the antimicrobial stewardship program is increasingly common.

3. Clinical Microbiologists:

  • The clinical microbiology laboratory is a key component in the function of antimicrobial stewardship programs.
  • provide Summary data on antimicrobial resistance rates that allow the antimicrobial stewardship team to determine the current burden of antimicrobial resistance in the hospital, facilitating decisions as to which antimicrobials to target for restriction or review.
  • They prepare antibiograms specific to certain patient care areas, especially intensive care units, that allow identification of local problems and focused antimicrobial stewardship and infection control efforts.
  • Also, having resistance data available on a monthly or quarterly basis allows closer tracking of trends and facilitates well-designed studies of interventions

4. Infection control staff and Hospital Epidemiologists:

  • Infection control staff gather highly detailed data on nosocomial infections which may assist in the antimicrobial stewardship team’s evaluation of the outcomes of their strategies.
  • Hospital epidemiologists have the expertise in surveillance and study design to lend to efforts studying the effect of antimicrobial stewardship measures.
  • In turn, antimicrobial stewardship programs may be able to assist in efforts to control outbreaks by focused monitoring and/or restriction of antimicrobials in the targeted units.

5. Hospital Administrators

  • Program funding, institutional policy, and physician autonomy are core issues in the development of antimicrobial stewardship programs that must be addressed by hospital administration.
  • Without adequate support from hospital leadership, program funding will be inadequate or inconsistent since the programs do not generate revenue (although they may result in significant cost savings).

6. Pharmacologists:

  • Pharmacologists need to be actively involved with microbiologists, infectious disease physicians, and others, informing an antimicrobial policy within the hospital.
  • Pharmacologists could also use their knowledge in activities such as prescription audits, feedback, and monitoring antimicrobial use throughout the hospital.
  • Another area would be in interpreting minimum inhibitory concentrations values when difficult treatment decisions have to be made due to AMR.

Types of ASP interventions:

Antimicrobial stewardship programs may be generally classified according to the strategy by which they seek to affect antimicrobial use. However, as noted, many programs use a combination of such strategies.

1. Education and Guideline Implementation Strategies:

  • To counter perceived conflicts in knowledge and practice, institutions may attempt to provide guidelines for antimicrobial use and educate clinicians regarding preferred antimicrobial therapy.
  • This strategy attempts to influence providers’ prescribing during their evaluation of the patient and the selection of antimicrobial therapy.
  • The approaches taken vary widely, from posting copies of national guidelines on the institution’s website to the formulation of consensus local guidelines with academic detailing and prescriber feedback.
  • Academic detailing refers to one-on-one educational sessions between an academic clinician-educator (usually a physician or pharmacist) and the clinician targeted for education.
  • Prescriber feedback consists of providing data to clinicians regarding their prescribing habits, with comparisons to expected norms (e.g., guidelines) or to other prescribers in the same practice area.
  • Although there is no shortage of evidence-based practice guidelines regarding antimicrobial use, including those addressing the problem of antimicrobial resistance, the mere publication of these guidelines is insufficient to significantly impact antimicrobial prescribing patterns.
  • Adaptation of national guidelines to local circumstances, collaboration with hospital specialists, broad dissemination of guidelines in easily accessible forms (print and/or electronic), and active educational methods such as academic detailing (targeted to the most influential clinicians first), are required to increase the chances of the adoption of recommendations in clinical practice.

2. Formulary and Restriction Strategies:

  • Because of poor compliance with guidelines for antimicrobial usage, external control over clinicians’ prescribing of these drugs may be implemented.

The different types of strategies used are:

Criterion monitored strategies

  • In this, only selected antimicrobial agents are freely dispensed by the pharmacy.
  • Other agents may only be available if certain criteria for use are met.

Prior-authorization strategies

  • In this, the antibiotics are dispensed if approval for use is obtained from a specialist in infectious diseases.

Closed-formulary strategies

  • the antibiotics may not be available at all.

3. Review and Feedback Strategies:

  • To optimize the use of non-restricted antimicrobials, or to manage the use of targeted antimicrobials in institutions where restriction strategies are not in place, programs built around antimicrobial review and feedback may be instituted.
  • Such a program involves the retrospective (hours to days) review of antimicrobial orders; if an order appears to be inappropriate, a member of the antimicrobial management team contacts the prescriber in an effort to optimize therapy.

4. Computer-Assisted Strategies:

  • The increasing computerization of the hospital environment offers new opportunities for programs to optimize antimicrobial use.
  • These opportunities have primarily been associated with the implementation of computerized physician order-entry systems in hospitals.
  • The order-entry encounter can be designed to facilitate each of the antimicrobial stewardship strategies above.
  • Educational strategies may be as simple as a link to the institution’s guidelines for therapy, or as sophisticated as computerized expert systems that integrate patient-specific laboratory and microbiology data in devising a suggested therapeutic regimen.
  • If a prescriber enters an order for a restricted agent, a list of formulary alternatives can be suggested, along with the pager number needed to obtain authorization.
  • When an agent targeted for review is ordered, the data can be forwarded in real-time or entered into a queue for later review by antimicrobial stewardship personnel.

5. Antibiotic Cycling Strategies

  • It is a strategy of rotating antimicrobials that might be effective in slowing the emergence of resistance to any one agent.
  • It involves scheduled rotation of antimicrobials in order to minimize the emergence of bacterial resistance.
  • These programs typically target gram-negative resistance (the cycled antimicrobials are those primarily active against gram-negative organisms) and are generally limited to the intensive care unit setting.

Outcome Measurements in ASP

varies widely, depending on program goals, study design, study duration, and measurement capabilities.

Common outcome variables related to antimicrobial usage include:

  • The change in antimicrobial usage is the most common outcome measured in studies of stewardship programs.
  • Measurement of antimicrobial usage may be performed from patient charts or as aggregate antimicrobial use (e.g., in defined daily doses per 1,000 patient-days) from billing or purchasing data.
  • Quantity of total antimicrobial use
  • Quantity of targeted antimicrobial use
  • Duration of therapy
  • Percentage of oral versus intravenous drug administration.
  • Antimicrobial drug expenditures- these are often measured to demonstrate the cost savings (or at least cost neutrality) associated with antimicrobial stewardship programs.
  • Clinical criteria are often included in studies to demonstrate that a change in antimicrobial usage does not have a deleterious effect on patient outcomes.
  • Common clinical outcomes include all-cause mortality, infection-related mortality, duration of hospitalization, and rates of readmission.
  • Clinical cure or improvement may also be measured, with or without a precise definition of the terms
  • Microbiologic outcomes include the percentage of organisms resistant to a certain antimicrobial, percentage of multi-drug-resistant organisms, or the number of infections due to specified organisms.

The available guidelines for ASP are:

1. IDSA: New Antimicrobial Stewardship Guideline 2016 – by Infectious Diseases Society of America.

2. Antimicrobial Stewardship: Guidelines – by The Society for Healthcare Epidemiology of America (SHEA)

3. Core Elements of Hospital Antibiotic Stewardship Programs by Centres for Disease Control and Prevention

4. Practice resources from the Association for Professionals in Infectious Control and Epidemiology (APIC)

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