Background: Antibiotic allergies are frequently reported in children, yet most reactions are mild and should not preclude first-line therapy. Inaccurate allergy labels contribute to increased healthcare costs, Clostridioides difficile infection, and suboptimal or unnecessary antibiotic use. We aimed to characterize the incidence and features of inpatient antibiotic-associated allergic reactions, including serious events, and to determine the proportion of antibiotic regimens that were inappropriately modified in response to reported allergies. Methods: We conducted a retrospective study of patients ≤18 years admitted to Severance Children’s Hospital (Republic of Korea) during 2022–2024 who received oral or intravenous antibacterials and had an antibiotic-related adverse drug reaction (ADR) documented as “allergy” in the electronic health record. ADRs to antiviral, antifungal, or antiparasitic agents and reactions occurring in outpatient or emergency settings were excluded. Each discrete sign or symptom attributed to an antibiotic was counted as one allergic-reaction event. Management was considered appropriate if first-line therapy was continued for mild reactions, discontinued when unnecessary, aligned with international or national guidelines, or reflected pediatric infectious diseases expert opinion. Results: Among 31,164 admissions, 17,614 (56.0%) patients received antibiotics. A total of 215 antibiotic-related ADRs (0.92%) were documented, including 161 allergic-reaction events in 122 patients (0.7%) associated with 143 antibiotic prescriptions. Males accounted for 59.0% of cases; median age was 7.8 years (IQR, 2.8–12.4). The most common indications were surgical prophylaxis (34.3%), systemic febrile illness (14.0%), and pneumonia (11.2%). Frequent manifestations included nausea/vomiting (32.3%), urticaria (23.6%), and non-urticarial rash (18.1%). ?-lactams accounted for 67.3% of implicated agents; the most frequent drugs were ceftriaxone (26.8%), vancomycin (15.7%), and ampicillin/sulbactam (5.9%). Anaphylaxis occurred in 6 patients (5.0% of reactions; 0.002% of antibiotic prescriptions). Overall, 28.7% of allergy-labeled reactions were managed inappropriately, and 8.4% resulted in unnecessary escalation to broader-spectrum antibiotics (Table 1). Surgical prophylaxis was associated with reduced odds of inappropriate management compared with therapeutic use (OR, 0.46; 95% CI, 0.22–0.99; P Conclusion: True antibiotic allergy in hospitalized children is uncommon, yet nearly one third of reported allergies led to suboptimal or inappropriate antibiotic use. With the recent launch of the national antimicrobial stewardship pilot program in Korea (November 2024), we plan to develop an evidence-based clinical pathway for antibiotic allergy management and incorporate de-labeling strategies into the hospital electronic system to optimize antibiotic selection.

Background: Diverticulitis is a common cause of emergency department (ED) visits for abdominal pain. Although recent guidelines recommend selective antibiotic use for low-risk cases, antibiotics remain commonly prescribed. Facility-level variation in prescribing practices has been underreported. Methods: We conducted a retrospective cohort study (2016–2023) using the Veterans Health Administration (VHA) Corporate Data Warehouse. We identified ED visits for a first episode of diverticulitis and excluded patients admitted within 48 hours. Low-risk cases were defined using International Classification Disease-10 codes for diverticulitis without perforation or abscess, Charlson Comorbidity Index <2, white blood cell (WBC) count <15 x 10^3 /?L, and C-reactive protein <14 mg/dL. We applied a multivariable mixed-effects logistic regression model with random facility intercepts to assess variation in antibiotic prescribing across VHA facilities, adjusting for patient demographics, WBC count, and facility complexity level. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated to assess the associations between patient-level variables and antibiotic prescription. Facility-level variation was quantified using the median odds ratio (MOR). Bootstrap resampling (2,000 iterations) was used to estimate 95% CIs for the MOR. Result: Among 4,214 patients (median age, 51 years; 84.6% male) from 72 facilities with ?10 eligible encounters, 176 (4.2%) did not receive antibiotics and 4,038 (95.8%) received antibiotics at ED discharge. Compared with patients who received antibiotics, those not receiving antibioitcs were less often White (72.1% vs. 76.7%). Abnormal WBC count was associated with antibiotic prescribing in the multivariable logistic regression model (adjusted OR 2.15 [95% CI: 1.13-4.08], p=0.019; Table). Facility-specific adjusted ORs ranged from 0.26 (95% CI: 0.14-0.48) to 1.50 (95% CI: 0.60-3.79), indicating heterogeneity in prescribing practices across the VHA system (Figure). The MOR for the facility-level variation in antibiotic prescribing was 1.70 (95% bootstrap CI: 1.00-2.22), suggesting a median 70% difference in the odds of receiving antibiotics between two otherwise identical patients treated at randomly selected facilities. In one significantly low-prescribing facility, review of 63 providers caring for 83 patients showed that among 13 providers who saw low-risk diverticulitis on more than three occasions, 10 prescribed antibiotics in all encounters, 2 in 50-99% of encounters, and 1 in 33%, suggesting provider-level variation. Conclusion: In this nationwide VHA cohort of low-risk diverticulitis, antibiotic prescribing varied across facilities after accounting for patient characteristics and facility complexity. The MOR indicates significant facility-level variation in antibiotic prescribing across facilities, highlighting opportunities for targeted antibiotic stewardship and implementation strategies to improve guideline-concordant care.

Background: Ceftriaxone and cefepime resistance among Enterobacterales continues to increase globally, partly due to the rising prevalence of extended-spectrum β-lactamase (ESBL) producing organisms. Surveillance of both resistance patterns and antimicrobial utilization is essential to inform empiric prescribing practices and stewardship strategies. Since carbapenems are frequently used to treat cephalosporin-nonsusceptible Enterobacterales infections, we evaluated trends in ceftriaxone and cefepime susceptibility among Escherichia coli and Klebsiella pneumoniae from 2012–2024 and institutional carbapenem utilization during overlapping years (2019–2025), following outcomes from the MERINO trial for management of ceftriaxone-resistant Enterobacterales infections. Methods: We conducted a retrospective review of annual cumulative inpatient antibiogram data for E. coli and K. pneumonia isolates for 2012-2024. Percent susceptibility to ceftriaxone and cefepime was assessed using Clinical and Laboratory Standards Institute (CLSI) breakpoints among a median of 1,532 E. coli isolates/year and 561 K. pneumoniae isolates/year. (Table 1). Institutional carbapenem utilization (combined meropenem and ertapenem use) was measured as days of therapy (DOT) per 1000 patient-days during 2019–2025 (not specifically representing treatment of E. coli or K. pneumoniae), following implementation of electronic medical record (EMR)–based antimicrobial utilization dashboards. Temporal trends were visualized using line plots. Pearson correlation coefficients (r) were calculated to assess percent susceptibility trends and carbapenem utilization during 2019–2024. Analyses are descriptive; no causal inference was made. Result: During 2012–2024, ceftriaxone susceptibility declined from 89% to 83% among E. coli and from 93% to 82% for K. pneumoniae, while cefepime susceptibility declined from 95% to 88% and 97% to 85% respectively (Figure 1). During the overlapping years 2019–2024, Pearson correlation showed modest downward susceptibility trends for ceftriaxone (E. coli r = −0.900, p = 0.014; K. pneumoniae r = −0.840, p = 0.036) and cefepime (E. coli r = −0.780, p = 0.067; K. pneumoniae r = −0.850, p = 0.033). Institutional carbapenem use increased from 15.2 to 19.3 DOT per 1,000 patient days between 2019 and 2025 (r = 0.79, p = 0.035) (Figure 2). Upon review, carbapenem use was substantially higher in hematology-oncology services (23.7–25.9 DOT/1000 patient-days, during 2022–2025) compared with overall institutional use (15.2–19.3 DOT/1000 patient-days). Conclusion: Ceftriaxone and cefepime susceptibility among Enterobacterales declined over the past decade, coinciding with a modest increase in institutional carbapenem use without a corresponding increase in carbapenem resistance during 2019-2024. Local susceptibility patterns and antimicrobial utilization data provide critical context for stewardship prioritization, especially in high-risk hematology-oncology populations.

Background: Antimicrobial stewardship programs use the NHSN standardized antimicrobial administration ratio (SAAR) to monitor antimicrobial use (AU) and direct activities, but only certain locations generate SAAR values. We explored the correlation between hospital SAAR coverage using days present (DP) and facility-wide AU measured in days of therapy per 1,000 days present (DOT/1,000DP). Methods: We included Nebraska hospitals reporting at least one adult location and at least six months of AU data that generated a SAAR during 7/2024-6/2025. We classified hospitals by bed size [large: <150, medium: 26–150, and critical access hospitals: ≤25]. Days present from SAAR eligible locations were divided by total facility DP to calculate the SAAR coverage proportion. We categorized hospitals in the upper third as having high SAAR coverage and those in the lower two-thirds as low SAAR coverage. We calculated Spearman correlation coefficients to evaluate the strength of the association between SAAR and AU rates in the high and low SAAR coverage groups. Results: Overall, 45 hospitals were included (median 25 beds, range 7-641) with large variability among total days present (473-228,051). Regarding SAAR coverage, 14 hospitals were classified as low coverage and 31 had high coverage (representing 47% and 83% of total DP, respectively), with an overall median SAAR coverage of 91% (Figure 1). When comparing the all-antimicrobial SAAR with the total AU rate of the top 14 antimicrobials, hospitals with low SAAR coverage showed weak correlation (? 0.163, p-value=0.57) compared to those with high coverage (? 0.901, p-value=<0.001) (Figure 2). Performance varied for other NHSN SAAR categories and AU rates in the low coverage group, with higher correlation between the GRAMPOS SAAR category and vancomycin DOT/1,000DP, and lower correlation between the BSHO SAAR category and the total AU rate of cefepime/piperacillin-tazobactam/meropenem use (Figure 3). Conclusion: In hospitals with low SAAR coverage, SAAR values may not accurately reflect overall facility-wide AU. This discrepancy is especially evident when evaluating overall antimicrobial use. We hypothesize that the weak correlation is likely a result of substantial AU in locations that do not generate a SAAR. We noted variation in AU rates in hospitals with similar SAAR values which may stem from the CDC’s predictive model although incomplete capture of antimicrobial use may be playing some role as well. These findings support CDC efforts to expand the SAAR to include new locations.

Background: Antibiotics are among the most frequently prescribed medications in skilled nursing facilities (SNFs), yet an estimated 40-75% of these prescriptions may be inappropriate or unnecessary. Vulnerability of SNF residents to antibiotic resistance, C. difficile, and adverse drug events make antibiotic stewardship programs (ASPs) crucial in these settings. Pharmacists are central to the success of ASPs, yet the scope of their responsibilities within Philadelphia SNFs is not known. Our team designed a survey to evaluate how consultant pharmacists are embedded in SNF ASPs, barriers to providing AS services, and interest in receiving further education. Methods: We designed a REDCap survey using the CDC Core Elements for AS in Nursing Homes and the Centers for Medicare & Medicaid Services’ Revised Long-Term Care Surveyor Guidance, which included facility-specific questions for each SNF served, as well as general questions. The survey was disseminated through a multi-modal approach to consultant pharmacists (n=26) identified through previous program activities and all Philadelphia SNFs (n=46) via email, phone, and collaborative meetings. Responses were summarized using descriptive statistics. Results: Fourteen pharmacists completed the survey, covering 23/46 (50%) Philadelphia SNFs. Eight pharmacists (57%) reported providing consulting services to <1 SNF in Philadelphia. Six pharmacists (43%) reported having formal training in AS or infectious diseases, and five (36%) served as the lead or co-lead of ASPs, covering 9/23 SNFs (39%). In 83% of SNFs, pharmacists were contracted to provide AS services for <5 hours per week. Limited contracted hours to perform AS activities was the most common consultant-related barrier to providing AS services, reported by 50% of pharmacists. The most commonly reported facility-related barriers were high rate of staff turnover (36%) and staff time constraints (29%). Pharmacists reported supporting a penicillin allergy delabeling program in 17% of SNFs and reported using antibiotic timeouts to assess antibiotic use in 13% of SNFs. Among the 79% of pharmacists interested in receiving further AS education, priority topics were building engagement and collaboration among staff, residents, and leadership (50%), clinical patient care (43%), and tracking, analyzing, and reporting AS metrics (30%). Conclusion: Health departments have an opportunity to enhance AS services delivered by SNF consultant pharmacists through educational outreach. Our survey identified penicillin allergy delabeling, initiating antibiotic timeouts, and AS metric reporting as priority topics. Systemic barriers, such as limited time for AS activities and staff turnover, were frequently reported. Addressing these barriers will be essential to enable sustained improvements in SNF ASPs.

Introduction Urinary tract infections (UTIs) are among the most common infectious diseases and rank as the second most prevalent infection worldwide. Objectives This study aimed to identify the species-specific distribution of pathogens in positive UTI cultures from both hospitalized and ambulatory patients and to evaluate the applicability of current UTI treatment guidelines in patients from Silesia, southern Poland. Patients and Methods In this retrospective, multicenter study, 85,485 urine samples collected in Poland between 2022 and 2023 were analyzed. Samples were obtained from inpatients (n = 52,294) and outpatients (n = 33,191) with suspected UTIs. Participants were categorized into three groups: premenopausal women, postmenopausal women, and men. Antibiotics were classified using the WHO AWaRe (Access, Watch, Reserve) framework. Results Overall, antibiotic susceptibility was low. The estimated risk of ineffectiveness of empirically prescribed therapies ranged from 26.7% to 44.6%, depending on whether patients were treated as inpatients or outpatients. Among inpatients, Escherichia coli showed 73% susceptibility to co-trimoxazole and ?86.9% susceptibility to cephalosporins only in premenopausal women, compared with approximately 76.6% in men and postmenopausal women. Klebsiella pneumoniae demonstrated susceptibility exceeding 80% only to cefoperazone/sulbactam (86.3%), while susceptibility to other agents remained below 60%. In outpatients, E. coli isolates were highly susceptible to nitrofurantoin (91.9%); however, most other Access-group antibiotics showed susceptibility rates below 60%, except gentamicin (92%). Resistance mechanisms were common: extended-spectrum ?-lactamase production was detected in 12.8% of outpatient and 32.9% of inpatient Enterobacterales isolates, while high-level aminoglycoside resistance was observed in 56.5% of inpatient Enterococcus faecalis and 63.7% of Enterococcus faecium. Conclusion Given the substantial risk of empirical treatment failure under current guidelines, their alignment with real-world clinical practice should be reassessed using more extensive and locally derived epidemiological data.

Background: Inappropriate antibiotic prescribing drives unnecessary healthcare expenditures and antimicrobial resistance. In 2022, the U.S. issued over 200 million outpatient antibiotic prescriptions, with 30% considered unnecessary. Although the clinical effects of overprescribing are well-known, its economic impact at the state level is less studied. This study estimated the financial burden of unnecessary antibiotic use in Tennessee in 2022 and examined differences based on age, rural or urban settings, and antibiotic class. Methods The IQVIA Medical Claims and Longitudinal Prescription Claims databases were used to perform a cross-sectional study evaluating the cost burden of unnecessary outpatient antibiotics dispensed from retail pharmacies in Tennessee from January 1–December 31, 2022. Antibiotic prescriptions were categorized into three tiers based on appropriateness using ICD-10 codes, with only Tier 3 (unnecessary) prescriptions included in the analysis. Prescriptions were aggregated by National Drug Code (NDC). Minimum, maximum, and average unit costs were obtained from Lexidrug-UpToDate and multiplied by the dispensed supply to estimate prescription-level costs. These costs were aggregated and stratified by age, residence, and antibiotic class. Results Conclusion Unnecessary antibiotic prescribing imposes a substantial economic burden, with annual costs reaching up to $245 million and notable out-of-pocket expenses for patients, disproportionately affecting older adults, rural residents, and certain antibiotic classes. Targeted stewardship interventions focusing on high-cost medications and prescribing patterns can reduce costs and antimicrobial resistance. Future research should evaluate tailored interventions and policies to promote proper prescribing across diverse demographic and geographic settings.

Background: Acute bacterial rhinosinusitis (ABRS) is a common, often self-limited condition that frequently leads to inappropriate antimicrobial prescribing in children. Continued reliance on the 2013 American Academy of Pediatrics (AAP) sinusitis guidelines and limited awareness of newer recommendations—particularly those supporting shorter treatment durations—have contributed to antibiotic overuse. As part of an enterprise-wide antimicrobial stewardship initiative, an intervention was implemented to support outpatient pediatric clinicians in identifying children most likely to benefit from antibiotics and in prescribing a 5-day course of guideline-concordant therapy consistent with the 2024-2027 AAP Red Book. We evaluated the impact of this intervention on prescribing practices and clinical outcomes. Methods A retrospective study was conducted among pediatric outpatients diagnosed with uncomplicated ABRS between January 1 and December 1, 2025 at an urban primary care pediatrics clinic within a large health system. The intervention consisted of a brief, targeted educational lecture delivered at a division meeting by pediatric antimicrobial stewardship leadership (pharmacist and physician), emphasizing updated guidance and promoting use of a sinusitis Epic order set. A one-page summary infographic was also distributed for reference. Data were extracted using Epic SlicerDicer and included patient demographics, clinical presentation, antibiotic selection and duration, use of the sinusitis order panel, and clinical outcomes. Outcomes before and after the intervention (May 14, 2025) were compared. Results A total of 99 pediatric patients with uncomplicated ABRS were included, with 55 treated before and 44 after the intervention. Use of the sinusitis order panel increased from 16% to 39% of encounters. The proportion of patients meeting diagnostic criteria for ABRS decreased slightly from 95% to 91%. Prescribing of 5-day antibiotic courses increased from 11% to 34%. There were no significant differences in prescribing provider type, antibiotic selection, or clinical outcomes—including Clostridioides difficile infection, return outpatient visits, or hospital admissions related to ABRS within 30 days—between patients receiving 5 versus <5 days of antibiotics (p<0.05). Conclusions A single, brief educational intervention paired with promotion of an Epic order set and summary infographic increased prescribing of shorter (5-day) antibiotic courses for pediatric ABRS without adversely affecting short-term clinical outcomes. Further studies are needed to assess the durability and long-term impact of this intervention on prescribing behavior.

Background: Our prior research demonstrated that Escherichia coli antimicrobial resistance varies geographically at a neighborhood level and antibiotic resistance risk is associated with patient demographics. This study aimed to examine whether antimicrobial resistance exhibits spatial dependence beyond individual-level risk factors. Methods: We performed retrospective geospatial analyses of patient characteristics and 2019-2024 E. coli antibiotic susceptibilities from Marshfield Clinic. Patients who had cultures positive for E. coli with susceptibility data were included with their first unique isolate per year (N = 36,043). All covariates were encoded as binary (0/1) indicators, including sex (female), farm residence, public insurance coverage, age under 18 years, age 65 years or older, White race, and antibiotic exposure within the prior 90 days. Outcomes included binary indicators of E. coli susceptibility vs non-susceptibility (intermediate or resistant) to ciprofloxacin (CIP), trimethoprim/sulfamethoxazole (SXT), cefazolin (CFZ), ceftriaxone (CRO), nitrofurantoin (FM), and tetracycline (TE). We first estimated standard logistic regression (binomial logit) models with antimicrobial non-susceptibility as the dependent variable and the full set of covariates as predictors. We then estimated spatial autoregressive probit models using Bayesian Markov Chain Monte Carlo methods (SAR-probit), which explicitly incorporates spatial dependence through a spatially lagged latent propensity. Spatial relationships were encoded using a K-Nearest-Neighbors-based spatial weights matrix constructed from point coordinates, with the neighborhood size (k = 25) selected based on a preceding calibration procedure. We compared non-spatial and spatial models to assess whether spatial clustering in antimicrobial resistance persists after accounting for demographic and exposure-related covariates. Results: Consistent with our prior results, logistic regression showed many patient demographics as significant independent predictors, with all variables significantly associated with ciprofloxacin resistance (p < 0.05) and some variation by variable with each of the other antibiotics. The spatial autoregressive parameter results indicated risk of E. coli non-susceptibility is influenced by nearby neighborhood non-susceptibility for all analyzed antimicrobials: CIP (rho = 0.633, p < 0.001), SXT (rho = 0.596, p < 0.001), CFZ (rho = 0.603, p < 0.001), CRO (rho = 0.639, p < 0.001), FM (rho = 0.708, p < 0.001), and TE (rho = 0.580, p < 0.001). Conclusions: An individual’s risk for an antibiotic-resistant E. coli infection is affected by their neighbors’ antibiotic resistance. This statistically significant geographic pattern in antibiotic resistance remains while accounting for known patient-level risk factors for antibiotic resistance. The results support patient-level strategies that are informed by community antibiotic resistance surveillance.

Background: Antibiotic overuse is common at hospital discharge. Antibiotic stewardship [ASP] metrics that capture antibiotic-prescribing at discharge can identify opportunities to optimize prescribing. We conducted a qualitative analysis of clinician perceptions of a novel risk-adjusted metric that shows the frequency and duration of oral antibiotics prescribed at discharge at Veterans Health Administration (VHA) hospitals. Methods: We conducted 91 semi-structured interviews with clinicians (e.g., ASP champions, hospitalists, pharmacists) from nine VHA facilities. Facilities represented three performance groups on the metric [Figure 1]: Group 1: less frequent antibiotic prescribing at discharge and shorter duration; Group 3: less frequent and longer duration; Group 4: more frequent and longer duration. During the interview, we presented the metric and explained its design and the facility's placement on the metric. Our interview guide prompted responses concerning clarity, fairness, utility of the metric for stewardship goals, and thoughts on the metric broadly. We conducted thematic analysis on interview transcripts. Results: The majority of clinicians from each performance group reported that the metric made sense and conveyed results clearly, expressing that the metric could support stewardship practices by reinforcing appropriate prescribing and identifying areas for improvement. Yet, many clinicians highlighted that they needed additional granular data to inform effective interventions, including service-specific prescribing, which infections are being overtreated, and how close their hospital is to being categorized in a different performance group. Clinicians often proposed a potential explanation for why their facility was in a specific performance group, including descriptions of strong ASP programs or reflections on patient complexity or services that may drive more frequent or longer prescribing. Responses on fairness varied across performance group and clinician role. Clinicians voiced concerns about the possible punitive use of the metric without considering whether it aligned with the appropriateness of antibiotic prescribing. Clinicians wanted more information about how the metric accounted for differences in patient case-mix. Conclusions: Our study found that clinicians generally considered the novel metric for comparing antibiotic prescribing at VHA hospital discharges to be clear and useful. This metric has potential to strengthen antibiotic stewardship by identifying areas needing improvement. However, clinicians emphasized the need for more granular data and raised concerns about fairness and potential punitive use. Addressing these points and clearly framing the metric as a tool for quality improvement will be essential for successful implementation.

Background:?It is unclear how antibiotic stewardship programs can effectively address antibiotic overuse at hospital discharge. A recent stepped-wedge cluster-randomized clinical trial evaluated the effectiveness of performing prospective audit-and-feedback on patients as they approached hospital discharge. In this study, we assessed barriers and facilitators to performing this intervention during the clinical trial. Methods: We performed a qualitative study using semi-structured interviews across ten acute-care hospitals participating in the trial, including three Veteran’s Health Administration (VA) hospitals, two academic medical centers and five community hospitals (Table 1). We created a semi-structured interview guide based on the RE-AIM framework to focus on perceptions of implementing the intervention. We interviewed 14 antibiotic stewardship personnel. All interviews were audio recorded, transcribed, and coded in a three-person team. Using thematic analysis, codes were developed and collapsed into themes. Results: Half of the intervention sites struggled to identify patients at discharge, limiting the stewardships teams’ ability to conduct prospective audit-and-feedback at discharge (Table 2). In contrast, strong provider-stewardship relationships and existing hospital initiatives, such as handshake stewardship and discharge rounds, facilitated implementation of the intervention (Table 3). Stewardship teams at four sites also reported challenges guiding antibiotic use for patients who had formal Infectious Disease consults, as prescribers typically preferred to follow the documented recommendations from the ID team. Conclusions: Our findings underscore the importance of accounting for the hospital and organizational context when implementing discharge-focused audit-and-feedback interventions, paying particular attention to existing policies, procedures, and the dynamics between antibiotic stewardship teams and front-line prescribers.

Background and Objective: Antipseudomonal antibiotics are frequently initiated empirically in hospitalized patients with suspected pneumonia. However, de-escalation often remains suboptimal. Behavioral “nudge” interventions in microbiology reporting have shown potential to enhance antimicrobial stewardship. In June 2022, our institution implemented a revised microbiology comment in sputum culture result reporting emphasizing “commensal respiratory flora only: no MRSA or P. aeruginosa”. This study aimed to evaluate whether this reporting nudge increased de-escalation of antipseudomonal therapy within 24 hours of final respiratory culture results. Methods: We conducted a retrospective cohort study of adults (<18 years) admitted between December 1, 2021 - May 31, 2022 (pre-intervention) and July 1–December 31, 2022 (post-intervention) who had respiratory cultures obtained and were started on at least one antipseudomonal antibiotic within 48 hours of the culture being sent. Patients were excluded if cultures grew P. aeruginosa, if another infection required antipseudomonal coverage, if therapy was required due to allergies, or if they had neutropenic fever. The primary outcome was de-escalation, defined as discontinuation or narrowing of antipseudomonal therapy, within 24 hours of the finalized respiratory culture report. Secondary outcomes included duration of therapy, hospital length of stay, Clostridioides difficile infection within 30 days, and in-hospital mortality. Outcomes were compared in pre- and post-intervention cohorts. Results: Of 230 screened patients, 175 met the inclusion criteria (107 pre-intervention, 68 post-intervention). Approximately one-third of subjects had community-acquired pneumonia(34 in pre-intervention and 28 in post-intervention). Baseline characteristics suggested the pre-intervention cohort had higher severity of illness, with more ICU admissions (N =68 in pre-intervention and N=28 in post intervention) and more hospital-acquired (N= 21in pre and N=8 in post) or ventilator-associated pneumonia (N=7 in pre, N=2 in post). De-escalation within 24 hours occurred in (76) 71% of pre-intervention patients and (50) 73.5% post-intervention (p=0.72). Median duration of antibiotics after final culture result was 1 day (IQR, -1,3) in the pre-intervention group and 0 days (IQR, -2,3) in the post-intervention group (P=0.36). Median hospital length of stay was significantly longer in the pre-intervention group (IQR 13(6,20) vs 9 (5,16); p=0.03). Rates of C. difficile infection (<5%) and in-hospital mortality did not differ significantly between groups. Conclusion: Implementation of a microbiology nudge comment in respiratory culture result reporting did not significantly increase antipseudomonal antibiotic de-escalation. High rates of de-escalation were observed even prior to the intervention. Explanations for the finding may be that respiratory cultures are being sent unnecessarily and, therefore, they are not being used as data to act upon and/or anti-pseudomonal antibiotics are being started empirically unnecessarily, particularly in patients with CAP. The cohorts did differ in severity of illness, which may have impacted the results. These findings highlight the need for additional education regarding guideline-directed respiratory culture utilization and empiric antibiotic choices.

Background: In early 2024, a nationwide healthcare system disruption in South Korea led to temporary suspension of the antimicrobial stewardship program (ASP) at a tertiary care center due to critical workforce shortages, which was accompanied by increased use of antibiotics, particularly restricted agents. In November 2024, a national ASP pilot program enabled reimplementation of ASP activities. We evaluated changes in hospital-wide antibiotic consumption following ASP reimplementation. Methods This retrospective, single-center study evaluated hospital-wide antibiotic use from March 2024 to November 2025 at a 2,446-bed tertiary care center (Asan Medical Center, Seoul). Antibiotics were classified as restricted agents subject to ASP interventions (preauthorization and prospective audit and feedback) and nonrestricted agents without such interventions. Changes in monthly days of therapy (DOT) per 1,000 patient-days were analyzed using interrupted time-series analysis, with November 2024 defined as the intervention time point. Results Over a 21-month study period, a total of 1,070,544 patient-days were included. Following reimplementation of the ASP, interrupted time-series analyses showed a reduction in total antibiotic use, corresponding to a 7.9% relative decrease (95% CI, 12.6% to −2.2%). This overall change was driven primarily by restricted antibiotics, which demonstrated significant reductions in both level (−29.8 DOT per 1,000 patient-days; 95% CI, 50.6 to −9.05; P = .012) and trend (−5.03 DOT per 1,000 patient-days per month; 95% CI, −7.65 to −2.41; P = .0015), yielding a 29.7% relative reduction (95% CI, −36.0% to −21.8%) compared with projected counterfactual use. In contrast, nonrestricted antibiotics showed no statistically significant changes. Conclusion Although reductions in restricted antibiotic use following ASP implementation are well recognized, our findings demonstrate that stewardship effects can be effectively restored after temporary program interruption. This resilience underscores the role of antimicrobial stewardship as a system-level safeguard against inappropriate antibiotic escalation, particularly in the context of healthcare system disruptions.

Background: Antimicrobial overuse increases antimicrobial resistance and adverse effects. Most antibiotics are prescribed in the ambulatory setting and up to half are inappropriate. We investigated the effect of a bundled stewardship intervention with active audit and feedback on antibiotic duration for two common infections, community acquired pneumonia (CAP) and skin and soft tissue infection (SSTI), in adult outpatients. Methods: From 2019-2021, institutional guidelines for management of CAP and SSTI were developed, and a dashboard to passively report data on provider-level antimicrobial durations for CAP and SSTI was created. From 2022-2023, clinical decision support tools promoting guideline-concordant antibiotic durations for both infection types were created in the Electronic Health Record. Education across all provider groups was completed throughout 2023. In the second quarter of 2023, personalized provider feedback reports (figure 1) on antimicrobial duration for CAP and SSTI were provided quarterly via electronic mail to individual providers. We performed an interrupted time series analysis of adult patients (age ≥21) prescribed an enteral antibiotic for CAP or SSTI within 3 days of a primary care encounter. The intervention period began one quarter after feedback was initially provided. Prescriptions of <3 days or <14 days were excluded as unlikely to represent uncomplicated infection. The primary outcome was proportion of patients prescribed appropriate antibiotic durations, defined as ≤5 days for CAP and ≤7 days for SSTI. Results: Eighteen quarters of data were analyzed (9 pre-intervention and 9 post-intervention). For SSTI (figure 2), there was no pre-intervention change in appropriate duration (p = 0.746). After intervention, there was an immediate increase in absolute proportion of appropriate antibiotic duration of 6.8 percentage points (p=0.009) with an ongoing increase of 1.25 percentage points each quarter (p=0.001). For CAP (figure 3), there was no pre-intervention change in appropriate duration (p = 0.44). There was no immediate change in absolute proportion of appropriate antibiotic duration (2.4%, p=0.698). After intervention, there was an ongoing increase in appropriate antibiotic duration of 2.69 percentage points each quarter (p=0.006), though not significantly different than the pre-intervention trend (p = 0.096). Conclusion: Clinician audit and feedback significantly improved antibiotic duration appropriateness for SSTI both immediately and progressively after implementation. Appropriate antibiotic duration for CAP also improved over time, though this was not significantly different than the pre-intervention trend. Active, individualized feedback to providers may be an effective strategy to improve appropriate antibiotic durations in ambulatory CAP and was an effective strategy for SSTI.

Background: The National Healthcare Safety Network (NHSN) Standardized Antimicrobial Administration Ratio (SAAR) is a widely used metric for benchmarking antimicrobial use and supporting antimicrobial stewardship efforts. The Centers for Disease Control and Prevention (CDC) Priority Core Elements of Hospital Antibiotic Stewardship Programs offer a complementary, framework-based approach to evaluating stewardship infrastructure and practices. Understanding the relationship between implementation of Priority Core Elements and SAAR performance may help clarify how structural stewardship components translate into measurable antimicrobial use outcomes. Tennessee Department of Health explored the association between NHSN SAARs and Priority Core Elements to better inform stewardship program evaluation and improvement strategies. Methods: Using 2023 NHSN data, TDH evaluated the relationship between all-antibacterial SAARs by overall Priority Core Element and by interventions that comprise each element. Aggregate SAAR data from qualifying adult units was utilized to create a hospital wide SAAR. Specific Priority Core Element components—including leadership, accountability, pharmacy expertise, action and reporting were analyzed. The tracking priority was excluded as participating hospitals had to submit antimicrobial use data to generate a SAAR. Associations between SAAR performance and presence of interventions for each included Priority Core Element were analyzed using t-tests in SAS 9.4. Results: Mean all-antibacterial SAAR declined with greater attainment of priority Core Elements (1.13, 1.07, and 1.01 for 0–2, 3–4, and 5 elements, respectively), though the difference was not statistically significant (p=0.31). Hospital leadership commitment was not associated with SAAR differences. Hospitals meeting the Accountability Core Element demonstrated significantly lower SAARs than those that did not (1.02 vs 1.14; p=0.035). Hospitals with physicians who completed infectious diseases fellowships (0.96 vs 1.10; p=0.004) or pharmacists who completed stewardship certificate programs (1.00 vs 1.11; p=0.027) demonstrated lower SAARs. Action and Reporting Core Elements showed trends toward lower SAARs. Facilities implementing treatment recommendations with both prospective audit and feedback and preauthorization had significantly lower SAARs (1.00 vs 1.13; p=0.014). Conclusion: Implementation of accountability and targeted stewardship training was associated with lower all-antibacterial SAARs, suggesting that specific structural and personnel-focused interventions may improve antibiotic use. Action and Reporting Core Elements demonstrated trends toward lower SAARs, but these were not statistically significant. Findings underscore the potential value of Priority Core Elements in guiding stewardship strategies; however, limited sample size may have reduced the ability to detect additional associations. Larger, multistate studies are needed to confirm these relationships and further elucidate how comprehensive Core Element implementation impacts antimicrobial use outcomes.

Background: Antibiotic allergy evaluation is an important antibiotic stewardship intervention, but is less commonly integrated into inpatient oncology care. Our objective was to evaluate the acceptability and feasibility of a pharmacist-driven penicillin allergy delabeling intervention for patients with hematologic malignancy (HM). Methods: We conducted a cross-sectional survey of physicians and advanced practice providers (APPs) who care for patients with HM at the Hospital of the University of Pennsylvania. The survey was administered from March 2025 to September 2025 in preparation for a planned Allergy Delabeling in Antibiotic Stewardship (RENEW) intervention. The survey included questions on current allergy evaluation practices, the perceived safety of RENEW and validated acceptability of intervention measure (AIM) and feasibility of intervention measure (FIM). AIM and FIM consist of 4 items scored 1-5 and is reported as a mean total score (5-20), with higher scores indicating greater acceptability and feasibility. Data were analyzed using descriptive statistics. Result: Of 70 eligible prescribers, 27 (38.6%) completed the survey: 21 (77.7%) physicians and 6 (22.2%) APPs. The majority (20, 74.1%) reported assessing documented antibiotic allergies of HM patients on admission and at the time an antibiotic is required (25, 92.6%). Nineteen (70.4%) respondents were comfortable modifying a documented antibiotic allergy in the medical record based on their assessment, while just under half (13, 48.1%) were comfortable deleting the allergy in the record based on their assessment. Nineteen (70.4%) respondents felt that penicillin skin testing was safe in patients with HM while 8 (29.6%) were not sure. Over half (14, 51.9%) were unsure if it is safe to evaluate penicillin allergy using an oral challenge based on clinical history without a skin test. The majority (22, 81.5%) said they would be comfortable having a patient’s antibiotic allergy removed from the medical record following negative allergy testing in the RENEW intervention. Compared to other patient safety initiatives, 24 (88.9%) believed evaluating documented antibiotic allergies is important or very important. Mean totals (SD; range) for acceptability and feasibility of the RENEW intervention were AIM, 17.2 (3.5; 8-20) and FIM, 17.7 (3.1; 8-20). Conclusion: Although the low response rate may limit generalizability, the majority of inpatient oncology clinicians perceived that a penicillin allergy delabeling intervention for patients with HM was acceptable and feasible to implement. Overall, clinicians believed that evaluating antibiotic allergy labels in patients with HM is an important and safe initiative, yet there was some uncertainty regarding the safety of a direct oral challenge.

Background: Previous studies have shown that unnecessary antibiotic use is common in outpatient settings, particularly for acute respiratory illnesses. We assessed changes in outpatient antibiotic prescribing and estimated the proportion of unnecessary prescribing to identify additional opportunities for improvement and evaluate progress toward national goals to improve antibiotic use. Methods: We used Merative MarketScan commercial claims (patients aged 0-19 and 20-64 years) and Centers for Medicare & Medicaid Services (CMS) Medicare carrier claims and Part D event files (patients aged ?65 years) to identify enrollees with medical and prescription drug coverage for 2019 and 2023. Enrollees were weighted by months of enrollment. Using ICD-10 codes, outpatient encounters were assigned to a single diagnosis using a tiered algorithm based on the most likely indication for antibiotics. Tier 1 included diagnoses for which antibiotics are indicated (e.g., pneumonia, urinary tract infection); tier 2 included diagnoses for which antibiotics are sometimes indicated (e.g., sinusitis, pharyngitis, suppurative otitis media); and tier 3 included diagnoses for which antibiotics are not indicated (e.g., bronchitis, viral upper respiratory infection). Oral antibiotics dispensed on the visit date or within 7 days afterward were linked to the encounters. We calculated the proportion and rate (per 100 patient-years) of antibiotic-associated encounters by tier and age group and reported percent change from 2019 compared to 2023. Results: The proportion of adult outpatient encounters resulting in an antibiotic prescription was lower in 2023 compared to 2019 across diagnostic tiers (Figure 1). The largest reduction occurred for tier 3 conditions, where antibiotic-associated encounters decreased by 32% among adults aged ?65 years and by 30% among adults aged 20-64 years. Tier 3 prescribing was highest for adults aged ?65 years. In 2023, the highest antibiotic prescribing rates were for tier 2 conditions, particularly among children aged 0-19 years (77 antibiotics/100 patient-years) and adults aged 20-64 years (43 antibiotics/100 patient-years) (Figure 2). Conclusions: Using nationally representative data, we found that adults had fewer healthcare visits associated with antibiotic prescriptions in 2023 compared with 2019, with the largest declines occurring for conditions for which antibiotics are unnecessary. However, there are still opportunities to reduce unnecessary antibiotic prescriptions, especially for older adults. Antibiotic stewardship efforts should also focus on conditions for which antibiotics are sometimes indicated (e.g., sinusitis). This includes assessing diagnosis-specific criteria for prescribing an antibiotic and evaluating antibiotic selection and duration to benchmark appropriateness and tailor improvement efforts.

Background: Sustaining reductions in inappropriate antibiotic prescribing for acute respiratory tract infections (ARTIs) remains challenging, with improvements often diminishing after stewardship interventions end. In a large, rural, non-profit, healthcare system with three high-volume urgent care centers (UCCs), an initial 11-month behavioral intervention reduced inappropriate prescribing for ARTIs; however, rates increased after intervention cessation. We evaluated whether reimplementing the same intervention could sustain reductions in inappropriate antibiotic prescribing in urgent care settings. Methods: We conducted a quasi-experimental interrupted time series (ITS) analysis using monthly data from October 2020 through October 2025. The reimplementation of monthly individualized feedback and quarterly blinded peer comparison emails began in February 2024. Prescribing trends were analyzed across four phases: Pre-Intervention (October 2020 - September 2021), Initial Intervention (October 2021 - August 2022), Post-Intervention (September 2022 - January 2024), and Reimplementation (February 2024 - October 2025). Mean prescribing rates were compared using descriptive statistics and analysis of variance (ANOVA). A Seasonal Autoregressive Integrated Moving Average (SARIMA) model accounted for autocorrelation and seasonality. Analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA). Results: Among 52,842 ARTI visits, 15,180 antibiotics were prescribed during the study period. Mean inappropriate antibiotic prescribing decreased from 41.7% (SD 9.79%) Pre-Intervention to 32.3% (SD 3.36%) during Initial Intervention, followed by an increase to 32.6% (SD 6.58%) Post-Intervention, and subsequent decline to 24.4% (SD 3.79%) during Reimplementation (Figure 1). ANOVA revealed significant differences across phases (F(3,57)P P PPPPP Conclusion: Reimplementation of a behavioral stewardship intervention was associated with a larger and sustained, though non-significant, reduction in inappropriate antibiotic prescribing for ARTIs. These findings suggest that ongoing or repeated stewardship efforts may be necessary to maintain prescribing improvements in outpatient urgent care settings.

Background: A limitation of National Healthcare Safety Network’s (NHSN) Standardized Antimicrobial Administration Ratio (SAAR) is incorporation of only facility and location-level characteristics in predictive antimicrobial use (AU) models (Table 1). Facilities with more medically complex patients may question SAAR’s applicability to their facilities due to lack of patient-level characteristics in predictive models. Case-mix index (CMI), a weighted average of a facility’s patient acuity, could be a marker of patient-level severity for comparison purposes. We investigated differences in SAAR values between facilities with different CMIs. Methods: We stratified Pennsylvania acute care hospitals (ACH) by CMI to compare median SAAR values between hospitals within each CMI quartile. We used 2024 SAAR values from adult inpatient locations using NHSN’s 2017 baseline predictive models. For CMI, we used Centers for Medicare and Medicaid Service’s (CMS) 2024 Diagnosis-Related Group at the hospital CMS Certification Number (CCN[KK1] ) level. CMI is defined at the CCN level while AU is reported under multiple NHSN organization IDs (orgIDs); therefore, observed and predicted antimicrobial days were summed across all orgIDs within each CCN to generate a single CCN-level SAAR for Adult All-Antibacterials. Hospitals were grouped into quartiles based on CMI and median SAAR values were calculated for each group. SAAR differences across CMI quartiles were assessed using the Kruskal–Wallis test. Result: Among 112 Pennsylvania CCN-level ACHs with complete AU and CMI data, hospitals were evenly distributed across CMI quartiles (N = 28 each; CMI range 1.26–2.88). Median SAAR values were similar across quartiles (Q1=0.96, Q2=0.97, Q3=0.92, Q4=0.92). SAAR did not differ significantly across quartiles (Kruskal–Wallis χ² = 1.94, p = 0.58). Boxplots showed substantial overlap in SAAR distributions across quartiles (Figure 1). Conclusion Median SAAR values did not differ significantly across CMI groups. Facilities serving more medically complex patients should not discount the SAAR based on lack of inclusion of patient-level characteristics in the predictive models. More research is needed to clarify if currently included SAAR predictive model variables are adequate proxies for patient acuity and if inclusion of additional patient-level factors would produce more accurate predictions. Our CMI dataset only included publicly available Medicare data, which may limit generalizability across age groups

Background: Over the past decade there has been an increased focus on infection prevention in post-acute care settings, including long-term care (LTC), skilled nursing facilities (SNF), rehabilitation facilities and home health. Many of these settings provide care for older people with complex care needs. Research has shown high rates of inappropriate antibiotic prescribing, with sub-optimal drug choice, dosing and duration – all targets for antimicrobial stewardship programs (ASP). Although national guidance is available, implementation remains challenging. In this study, we explored the structure and leadership of ASP in a variety of post-acute care settings from an infection prevention perspective. Methods: Infection Preventionists (IPs) were invited to participate in the 5-yearly Association for Professionals in Infection Prevention (APIC) Megasurvey. The electronic survey was advertised using snowball recruitment by APIC between June 6 and July 31, 2025. Data were collected on ASP characteristics, including structure and leadership of programs, and resources available to support appropriate prescribing. Descriptive statistics were used to summarize the data. Results: A total of 489 respondents reported working in post-acute settings. Of these 239 (49%) worked in long term care, 200 (41%) in skilled nursing facilities, 26 (5%) in inpatient rehabilitation and 24 (5%) in home health. Facility-based post-acute care IPs overwhelmingly reported the existence of ASPs (LTC-82%; SNF/Rehabilitation – 93%) with a committee having oversight (LTC-86%; SNF/Rehabilitation – 80%). This governance function was often incorporated into infection prevention committees (LTC - 52%; SNF/Rehabilitation – 43%). In LTC, ASPs were led by a range of healthcare professionals including IPs (27%), infectious diseases (ID) physicians (10%), ID pharmacists (10%), pharmacists (non-ID) (23%), and other medical professionals such as internists (22%). In SNFs/ Rehabilitation facilities, a similar pattern was observed. IPs reported they had up-to-date recommendations available for infection management (LTC - 88%, SNF/Rehabilitation -83%), and around half also noted existence of regular rounds to allow inquiry about appropriate antibiotic prescribing (LTC - 52%, SNF/Rehabilitation - 53%) Only 29% of IP respondents from home health reported having an ASP. Although numbers are small, it appears that 70% of these programs had the governance of an ASP Committee but there was little IP involvement in leadership or antibiotic prescribing review activities. Conclusion: This study provides unique insights into ASP in post-acute care. Programs are now well-established in many facility types. More work is needed to understand and help IPs develop ASP expertise relevant for post-acute settings, particularly in home health.