prospective audit and feedback (PAF)
Antibiotic stewardship refers to systematic measurement and coordinated interventions designed to promote optimal use of antibiotic agents, by advocating selection of appropriate antibiotic drug regimens (including dosing, duration of therapy, and route of administration).
The primary goal of antibiotic stewardship is to optimize clinical outcomes while minimizing unintended consequences of antibiotic use (including toxicity, selection of pathogenic organisms such as Clostridium difficile, and the emergence of antimicrobial resistance).
In general, management of patients with suspected or proven bacterial infection consists of initiation of empiric therapy (ie
, prior to availability of definitive microbiology data), followed by adjustment once microbiology data become available.
Antibiotic oversight should include prospective audit and feedback (PAF), preauthorization, or both. In programs that use PAF, trained staff review antibiotic orders and advise regarding optimization of antibiotic use. In programs that use preauthorization, approval is required before certain agents may be administered.
Antibiotic stewardship programs should develop facility-specific clinical practice guidelines for common infections based on local epidemiology, susceptibility patterns, and drug availability or preference.
Pharmacy-led interventions can be used by pharmacists to optimize antimicrobial therapy, including dose optimization (eg, vancomycin dosing) and systematic conversion of intravenous to oral antimicrobial therapy.
Correcting an inaccurate antibiotic allergy history
in the medical record can be very useful for guiding subsequent decisions regarding a patient's antibiotic therapy.
The clinical microbiology laboratory has an integral role in promoting appropriate antibiotic use, by providing ongoing culture results and susceptibility data, preparing an annual antibiogram, and providing guidance regarding implementation and interpretation of rapid diagnostic tests.
The optimal metrics for monitoring stewardship programs are uncertain. Traditionally, programs have focused on antibiotic use and cost savings; focusing on outcome and process measures may better illustrate a program's value and sustainability.
Tailoring antibiotic therapy ("antibiotic time-out")
In patients receiving empiric antibiotic therapy, the regimen should be reevaluated on a continuing basis as the clinical status evolves and microbiology results become available (often after 48 to 72 hours). At this point, an "antibiotic time-out" should be performed, in which microbiology results are reviewed and antibiotic therapy is adjusted from empiric to definitive antibiotic therapy. The spectrum of coverage may be narrowed or broadened as appropriate, the dose may be adjusted as needed, and unnecessary components of the regimen should be eliminated. If it is apparent that the patient's clinical status is not the result of bacterial infection, antibiotics may be discontinued altogether. During the antibiotic time-out, the indication and duration of antibiotic therapy should be estimated and stated in the medical record.
Point-of-care interventions by pharmacy
Inpatient point-of-care protocols can be used by pharmacists to optimize antimicrobial therapy, including dose optimization (eg, vancomycin dosing, extended infusion
administration of beta-lactams), dose adjustments in the setting of organ dysfunction, and automatic conversion of intravenous to oral antimicrobial therapy.
Transition from intravenous to oral therapy
Stewardship programs can develop a protocol defining the appropriate patients for this intervention, taking into account the indication for therapy, the suitability of the oral agent's coverage and bioavailability, the patient's clinical stability, and the patient's ability to tolerate oral or enteral medications. Pharmacy-driven protocols allow the pharmacist to make the transition in acceptable clinical situations for highly bioavailable antibiotics (including fluoroquinolones, azithromycin, trimethoprim-sulfamethoxazole, metronidazole, fluconazole, and others)
Measuring antibiotic use and cost savings
Antibiotic use may be estimated in days of therapy (DOT) or defined daily dose (DDD); use of DOT is preferred.
DOT is an aggregate sum of days for which any amount of a specific antibiotic agent is administered to a particular patient (numerator) divided by a standardized denominator. DOT refers to the number of days a patient receives an antibiotic, regardless of the dose administered. Therefore, the calculation can be distorted if a patient receives more than one antibiotic agent (for example, if a patient receives 2 antibiotics for 7 days, the DOT equals 14) or if a patient receives antibiotics administered every other day. DOT can be used for both pediatric and adult populations. Cost cannot be calculated easily based on DOT because dose is not included. The United States Centers for Disease Control and Prevention (CDC) Antibiotic Use (AU
) option collects and reports DOT data through the National Healthcare Safety Network (NHSN). Participation in the AU
option is voluntary.
DDD aggregates the total number of grams of each antibiotic administered during a period of time divided by a standard DDD designated by the World Health Organization (WHO). Because the data needed are typically available from the pharmacy, it is relatively easy to calculate. However, DDD underestimates the antibiotic exposure in patients with renal failure and does not account for weight-based dosing, making this metric inappropriate for pediatric populations.
Cost should be assessed according to drugs administered or prescribed (not just purchased) and should be normalized for census.