Emergency Department Antimicrobial Stewardship: A Critical Area of Focus for Health Systems

ContagionContagion, June 2023 (Vol. 08, No. 3)
Volume 08
Issue 3

As the first line of acute care, emergency departments are key stewards of antibiotics.

With more than 150 million US visits and 10 million antimicrobial prescriptions provided annually, the emergency department (ED) is a critical area for antimicrobial stewardship programs (ASPs) to assess antimicrobial prescribing and develop targeted interventions for improvement.1,2 Uniquely situated at the juxtaposition of inpatient and outpatient care, antimicrobial prescribing decisions made within the ED can impact local resistance patterns in both the community and hospital settings.

Although some of the same core strategies of ASPs can be implemented in the emergency department setting, practices such as audit and feedback or formulary restriction should be tailored to support optimal prescribing, while also limiting barriers to timely care in an often high-throughput and high-acuity setting. Additionally, collaboration with key stakeholders such as emergency medicine pharmacists or ED physician champions can greatly improve the success of stewardship practices. As multifaceted interventions are often necessary to produce optimal prescribing, in this article, we highlight essential areas of focus for the implementation and maintenance of ED ASPs and strategies to support implementation.


While not a core strategy of ASPs, educational interventions support success by laying a foundation for program initiatives. As a wide variety of patients seek care in the ED, educational needs can range from how to optimize prescribing in sepsis and critical illness to acute cystitis or sexually transmitted infection treatment. Educational interventions have been shown to have a beneficial impact on behaviors related to prescribing; however, continuous education is typically necessary for sustained impact.3 Regarding implementation of educational activities, we recommend that ASP leaders provide at least annual live education to ED staff, including pertinent antibiogram and guideline updates. Annual education should include collaboration with the ED pharmacist(s) or physician champion, if available, to demonstrate partnership between the ASP and ED teams. Intermittent educational activities may additionally include webinars, pocket card resources, or live updates of urgent initiatives.

Local resources aligned with educational interventions are powerful tools for ASPs. While many hospital ASPs have already developed inpatient antibiogram and empiric therapy guidelines with corresponding order sentences within the electronic health record (EHR), outpatient antibiograms, guidelines, and EHR optimization may not have been prioritized but can greatly impact ED discharge prescribing decisions. Additionally, local guidelines can serve as the standard for optimal prescribing when providing feedback on antibiotic decisions. A study by Percival and colleagues evaluated the impact of an educational intervention combined with local antibiogram and guidelines development on discharge antimicrobial prescribing from the ED for urinary tract infections (UTIs). The authors saw significant improvement in guideline-concordant antibiotic selection (44.8% vs 83%; P < .001) between the pre- and postintervention groups.4 A similar study by Hecker and colleagues showed an increase in guideline-concordant discharge antibiotic prescribing for UTI in the ED following education plus EHR order set implementation (44% vs 68%; P < .001) and a decrease in unnecessary antibiotic days (250 vs 119 days; P < .001).5 While local resources are ideal, sites must consider potential barriers and ways to overcome them. Antibiogram development must be coordinated with the microbiology laboratory; while some sites have onsite microbiology staff and testing, that is not the case at all institutions, which may make obtaining outpatient isolates difficult. In some cases, the hospital inpatient antibiogram or a regional antibiogram may be necessary to use to guide prescribing and empiric therapy guideline development. Additionally, EHR order sentence optimization typically requires the submission of a request and approval before implementation. At large health systems, this may require a majority vote or consensus, which can significantly delay or prevent implementation at the local level. Local ASPs may look for alternative methods to optimize the EHR, including creating/owning local provider “favorite” order sentences that can be shared with the whole team but are outside the preset selections of the EHR.


Antimicrobial stewardship interventions targeting specific syndromes (eg, respiratory tract infection [RTI] and UTI) have shown to be effective in optimizing antimicrobial prescribing.6 Respiratory illnesses remain a leading cause of ED visits, and distinguishing between viral and bacterial causes is an ongoing challenge. Several rapid molecular diagnostic tools have been developed with the ability to detect a wide array of atypical bacteria and viruses in an effort to improve diagnosis and prescribing. Studies have shown positive impact on diagnoses; however, impact on antimicrobial use has not been as consistent. Rappo and colleagues compared treatment outcomes using a rapid upper respiratory polymerase chain reaction panel vs conventional diagnostic methods in 337 adult patients admitted to the ED.7 They found no difference in antimicrobial use among hospitalized patients with a positive viral test result; however, a significant decrease in hospital admissions was seen in patients diagnosed with noninfluenza viruses despite initially being identified for admission (21% vs 5%; P = .049). When further considering how to improve diagnosis and treatment of patients presenting to the ED with RTIs, procalcitonin is a biomarker that when negative may help in ruling out bacterial infection. However, procalcitonin levels can be affected by several noninfectious factors, which may result in decreased reliability.8

Data regarding the impact of procalcitonin on antibiotic use have been mixed. A multicenter, randomized controlled trial performed in 6 tertiary care EDs in Switzerland found that initiating a procalcitonin algorithm reduced antibiotic exposure for lower RTIs (5.7 vs 8.7 days) without increasing risk for serious adverse events (15% vs 18.9%).9 However, Huang et al performed a multicenter, randomized, controlled trial in US EDs and found procalcitonin had no impact on antimicrobial prescribing rates for lower RTIs. Over 92% of patients had a procalcitonin level less than 0.25 μg/L, yet over 35% of ED patients received antibiotics.10 If using RTI rapid diagnostics and procalcitonin in the ED to guide antimicrobial prescribing, collaboration with the ASP is critical to ensure appropriate use and that results are acted upon appropriately and in a timely manner. Developing local resources with diagnostic pearls containing flow diagrams and guidance for when to order and how to interpret results can be helpful to improve judicious testing and appropriate antimicrobial use in RTI. Audit and feedback continues to be a powerful tool for discussing positive viral panel and negative procalcitonin results, thereby decreasing inappropriate antimicrobial use. Health systems that have observed suboptimal implementation of rapid diagnostic testing have benefited from eliminating tests (eg, procalcitonin) or placing ordering restrictions (eg, infectious disease consultation or symptom verification) to steward testing resources.

Finally, UTI and asymptomatic bacteriuria (ASB) are additional syndromes that should be high priority for ASP interventions within the ED. Urine testing, including urinalysis (UA) and urine cultures, within the ED can have a tremendous impact on downstream antimicrobial prescribing. The UA has long been reported as a routine diagnostic practice because of accessibility of a noninvasive test with rapid results; however, UA is a poor positive predictor of UTI. The presence of ASB and pyuria are common and occur in up to 50% of patients. The Infectious Diseases Society of America provided updated guidelines in 2019 recommending against routine UA and urine culturing in patients without signs or symptoms consistent with UTI.11 Despite these recommendations, changes in practice reflecting these updated best practice recommendations have been slow. A recent multicenter, retrospective cohort study evaluated testing and treatment of ASB among 2461 patients admitted through the ED. The authors found that most (80%) patients with ASB had testing and treatment initiated by ED providers and antibiotics were often continued upon admission. Treatment of ASB was associated with increased risk of Clostridioides difficile and longer hospitalization.12 Another retrospective cohort study evaluated adult ED patients at risk for UTI misdiagnosis and discharged from the ED. Of 54,005 patients evaluated, abnormal UA was associated with inappropriate UTI diagnosis, antibiotic use, and longer ED lengths of stay.13 Risk of ASB overtreatment is further exacerbated by urine culture results being available as patients may be under the care of a different provider who was not present for the initial evaluation; this can create pressure to treat based on culture results. Many institutions have had success in decreasing antibiotic use in ASB by eliminating reflex urine cultures from UA results. Interventions aimed at reducing unnecessary UA and urine cultures performed in the ED should be a high priority for ASPs to improve appropriate diagnosis and prescribing. Such interventions include eliminating prechecked UA and urine cultures from admission order sets, removal of reflex urine cultures from UA results, and requiring ordering providers to select an indication or symptom verification prior to urine culture.


A core strategy of inpatient antimicrobial stewardship programs, prospective audit and feedback can be impactful in the ED but potentially difficult to implement depending on local resources. Audit-and-feedback strategies are crucially important for patients being both admitted to and discharged from the ED. Emergency medicine clinical pharmacists are typically best positioned to implement prospective audit and feedback, being physically located within the ED and having established relationships with ED providers. Pharmacist leaders of ASPs should look to partner with ED pharmacists, when able, to optimize stewardship initiatives. Kulwicki and colleagues demonstrated that ED pharmacist-led audit and feedback significantly increased guideline-concordant prescribing for pneumonia and intra-abdominal infections for patients being admitted to the hospital (61% vs 78%; P = .001); additionally, more than 80% of ED orders were continued upon admission, demonstrating the impact of antibiotic prescribing inertia.14 Audit and feedback in the ED may be established in a variety of ways; sites with onsite ED pharmacists may utilize clinical decision support software (CDSS) alerts or manual ED pharmacist audit of the ED tracking board to identify patients receiving antimicrobial therapy requiring intervention. For sites without ED pharmacist presence or 24/7 ED pharmacist coverage, some level of prospective audit and feedback should be provided by non-ED pharmacists when verifying orders prior to patient administration.

Similar to educational interventions, once ED audit-and-feedback processes are established, they must be prioritized and maintained for continued impact. Tagashira et al demonstrated a significant decrease in guideline-appropriate antibiotic prescribing following removal of a multifaceted stewardship intervention within the ED that included infectious diseases physician-led audit and feedback (83.4% vs 71.8%; P < .001). Health system ASP and ED personnel along with information technology resources must be assessed and periodically reevaluated to determine how best to efficiently conduct and sustain effective audit-and-feedback processes.15 This may include involving pharmacists outside ED pharmacy specialists (eg, ASP pharmacists, residents, or generalists) in the process of prospectively reviewing orders prior to verification and providing feedback, as well as evaluating opportunities to improve efficiency in identifying patients needing intervention, such as CDSS software and ED-specific rules, or a requirement for verification of all antimicrobial orders prior to administration or at discharge.


Addressing antimicrobial transitions of care needs following an ED visit is an important aspect of ASPs. Because antimicrobial prescribing in the ED is often empiric, ED culture follow-up programs have emerged as an opportunity to improve antimicrobial use and patient outcomes. There are many published studies outlining the benefits of culture follow-up programs in the ED (TABLE 1). Most of these programs highlight the role of the pharmacist as an ASP leader and the benefit of collaboration with providers and nursing staff in the ED. Many pharmacist-led culture follow-up programs are conducted under collaborative practice agreements (CPAs), allowing for independent follow-up of common infectious disease states such as UTI, URI, sexually transmitted infections, and skin and skin structure infections. Comprehensive CPAs include responsibilities such as culture review, counseling, and documentation, and they outline the personnel able to carry out each responsibility, which may include ED, ASP, generalist, and trainee pharmacists. At hospitals or sites with fewer personnel resources (eg, critical access hospitals), offsite pharmacists may carry out culture follow-up responsibilities remotely.

Structured culture follow-up programs can result in faster time to patient follow-up, improved guideline-concordant prescribing, and decreased short-term readmission or reevaluation in the ED.16-19 The benefits of culture follow-up programs are well established for positive cultures and need for intervention; however, there is less known about the burden of empiric antimicrobials prescribed for negative cultures. There may be significant opportunities for ASPs to discontinue antibiotics when cultures are negative, thereby limiting unnecessary antibiotic exposure, decreasing risk for development of resistance, and avoiding adverse drug reactions.20 While ED stewardship and culture follow-up programs may not be standard of care at every institution, these practices can significantly improve patient care through optimizing antimicrobial use at transitions of care into the outpatient setting. Opportunities to implement and sustain such programs should be evaluated by health system ASPs.


The ED represents an important care area where ASPs have an impact on community and hospital antimicrobial use. Collaboration between pharmacists, physician champions, and the antimicrobial stewardship team can help ensure local resources are used judiciously leading to appropriate diagnosis and improved antimicrobial prescribing.


  1. Cairns C, Ashman JJ, Kang K. Emergency department visit rates by selected characteristics: United States, 2019. NCHS Data Brief.2022;(434):1-8.
  2. Outpatient antibiotic prescriptions — United States, 2021. Centers for Disease Control and Prevention. Reviewed October 4, 2022. Accessed April 20, 2023. https://www.cdc.gov/antibiotic-use/data/report-2021.html
  3. Sangwan R, Neels AJ, Gwini SM, Saha SK, Athan E. Is education alone enough to sustain improvements of antimicrobial stewardship in general practice in Australia? Results of an intervention follow-up study. Antibiotics (Basel). 2023;12(3):594. doi:10.3390/antibiotics12030594
  4. Percival KM, Valenti KM, Schmittling SE, Strader BD, Lopez RR, Bergman SJ. Impact of an antimicrobial stewardship intervention on urinary tract infection treatment in the ED. Am J Emerg Med. 2015;33(9):1129-1133. doi:10.1016/j.ajem.2015.04.067
  5. Hecker MT, Fox CJ, Son AH, et al. Effect of a stewardship intervention on adherence to uncomplicated cystitis and pyelonephritis guidelines in an emergency department setting. PLoS One. 2014;9(2):e87899. doi:10.1371/journal.pone.0087899
  6. Hecker MT, Son AH, Murphy NN, et al. Impact of syndrome-specific antimicrobial stewardship interventions on use of and resistance to fluoroquinolones: An interrupted time series analysis. Am J Infect Control. 2019;47(8):869-875. doi:10.1016/j.ajic.2019.01.026
  7. Rappo U, Schuetz AN, Jenkins SG, et al. Impact of early detection of respiratory viruses by multiplex PCR assay on clinical outcomes in adult patients. J Clin Microbiol. 2016;54(8):2096-2103. doi:10.1128/JCM.00549-16
  8. Samsudin I, Vasikaran SD. Clinical utility and measurement of procalcitonin. Clin Biochem Rev. 2017;38(2):59-68.
  9. Schuetz P, Christ-Crain M, Thomann R, et al. Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial. JAMA. 2009;302(10):1059-1066. doi:10.1001/jama.2009.1297
  10. Huang DT, Yealy DM, Filbin MR, et al. Procalcitonin-guided use of antibiotics for lower respiratory tract infection. N Engl J Med. 2018;379(3):236-249. doi:10.1056/NEJMoa1802670
  11. Nicolle LE, Gupta K, Bradley SF, et al. Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of America. Clin Infect Dis. 2019;68(10):e83-e110. doi:10.1093/cid/ciy1121
  12. Petty LA, Vaughn VM, Flanders SA, et al. Assessment of testing and treatment of asymptomatic bacteriuria initiated in the emergency department. Open Forum Infect Dis. 2020;7(12):ofaa537. doi:10.1093/ofid/ofaa537
  13. Childers R, Liotta B, Brennan J, et al. Urine testing is associated with inappropriate antibiotic use and increased length of stay in emergency department patients. Heliyon. 2022;8(10):e11049. doi:10.1016/j.heliyon.2022.e11049
  14. Kulwicki BD, Brandt KL, Wolf LM, Weise AJ, Dumkow LE. Impact of an emergency medicine pharmacist on empiric antibiotic prescribing for pneumonia and intra-abdominal infections. Am J Emerg Med. 2019;37(5):839-844. doi:10.1016/j.ajem.2018.07.052
  15. Tagashira Y, Goto M, Kondo R, Honda H. Multifaceted intervention for improving antimicrobial prescription at discharge in the emergency department. Infect Control Hosp Epidemiol. 2022;43(1):88-91. doi:10.1017/ice.2020.1436
  16. Randolph T, Parker A, Meyer L, Zeina R. Effect of a pharmacist-managed culture review process on antimicrobial therapy in an emergency department. Am J Health Syst Pharm. 2011;68(10):916-919. doi:10.2146/ajhp090552
  17. Baker S, Acquisto N, Ashley E, Fairbanks R, Beamish S, Haas C. Pharmacist-managed antimicrobial stewardship program for patients discharged from the emergency department. J Pharm Pract. 2012;25(2):190-194. doi:10.1177/0897190011420160
  18. Giruzzi ME, Tawwater JC, Grelle JL. Evaluation of antibiotic utilization in an emergency department after implementation of an antimicrobial stewardship pharmacist culture review service. Hosp Pharm. 2020;55(4):261-267. doi:10.1177/0018578719844171
  19. Cornell K, Hile G, Stone T, Hannum J, Reichert M, Hollinger M. Impact of advanced practice pharmacists on a culture response program in the emergency department. Am J Health Syst Pharm. 2022;79(suppl 4):S106-S114. doi:10.1093/ajhp/zxac157
  20. Geyer AC, Draper HM, Wolf LM, Buss PM, Dumkow LE. Feasibility evaluation to expand a collaborative practice agreement and discontinue antibiotics after an emergency department or urgent care visit. Am J Health Syst Pharm. 2023;zxad063. doi:10.1093/ajhp/zxad063
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