Antimicrobial stewardship

Antimicrobial stewardship (AMS) refers to coordinated efforts to promote the optimal use of antimicrobial agents, including drug choice, dose, route of administration, and duration of therapy.

Every time an antimicrobial agent is used, whether or not that use is justified, it applies selective evolutionary pressure to microbial populations which can result in acquired antimicrobial resistance. Antimicrobial resistance genes can then spread to other microbes in the host or their environment, including those organisms that can live on your skin or in your body where they coexist with the host. Antimicrobial use can also cause additional unintended consequences, such as disruption to the normal microbiome (i.e., dysbiosis) as well as direct toxic effects on people and animals, including damage to kidneys, liver, teeth and bones. These unintended consequences are often referred to as "collateral damage". Antimicrobial therapy is justified when the benefits outweigh these risks.

Definition and goals

In 2007, the Society for Healthcare Epidemiology of America (SHEA) defined AMS as a set of coordinated strategies to improve the use of antimicrobial medications with the goal to:

enhance patient health outcomes

reduce antibiotic resistance, and

decrease unnecessary costs

reduce/eliminate any unnecessary applications of antimicrobials, i.e. to stem antimicrobial overuse, e.g., giving antibacterial drugs for viral infections

ensure that human and animal patients who need antimicrobials receive the optimal drug for them, at the correct time, at an effective dose, via the correct route, for the minimum effective duration

minimize environmental contamination with antimicrobial agents

Decreasing the overuse of antimicrobials is expected to serve the following goals:

improve patient outcomes, especially patient safety

decrease adverse drug reactions such as hypersensitivity reactions or kidney or heart damage (e.g., QT prolongation)

decrease antibiotic-associated disease, such as Clostridioides difficile–associated diarrhea, other antibiotic-associated diarrhea, and invasive candidiasis

guard the patient's microbiome, including the gut flora, respiratory tract flora, urogenital tract flora, and skin flora (this is closely related to the preceding goal of preventing antibiotic-associated disease)

decrease wasted costs

slow the increase in antimicrobial resistance

prevent unforeseen environmental degradation, such as likely adverse effects of altering biotas and animal microbiotas by pervading the water cycle with antimicrobials in wastewater

History

Antimicrobial misuse was recognized as early as the 1940s, when Alexander Fleming remarked on penicillin's decreasing efficacy, because of its overuse. However, the first systematic assessment of antibiotic use wasn't published until 1966 from a study that took place at Winnipeg General Hospital in Manitoba, Canada. Two years later, in 1968, others estimated that 50% of antimicrobial use was either unnecessary or inappropriate.