Dinnes, Laura

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.

OBJECTIVE Overuse of broad-spectrum empiric antimicrobials remains common in children hospitalized with respiratory tract infections (RTI). A negative methicillin-resistant Staphylococcus aureus (MRSA) nasal swab (MNS) polymerase chain reaction (PCR) result has been shown to have a high negative predictive value for MRSA in RTI. In this quality improvement (QI) initiative, we developed a pharmacist-driven approach to reduce the duration of empiric vancomycin for RTI in children. The primary aim was the time to de-escalation of vancomycin, and the secondary aim was the reduction in vancomycin monitoring in patients hospitalized with RTI. METHODS Baseline duration of vancomycin therapy was assessed by conducting a retrospective chart review. After root cause analysis and engaging key stakeholders, an electronic health record OurPractice Advisory (OPA) was implemented, prompting pharmacists to order an MNS PCR during order verification for vancomycin with an RTI indication. RESULTS Preimplementation (01/01/2021 to 08/31/2023) included 89 patients, and 25 postimplementation (09/21/2023 to 05/31/2024). We found a 36% decrease in mean vancomycin duration from 53 to 34 hours after implementation of the pharmacist-driven OPA. Postimplementation, 24% of patients had a vancomycin concentration obtained, compared with 37% preimplementation. No patients were readmitted within 30 days postimplementation, compared with 1 patient preimplementation. CONCLUSIONS This QI initiative provides preliminary data that empiric vancomycin duration in pediatric patients with RTI may be impacted by pharmacist-facing OPA implementation, prompting ordering of MNS PCR at the time of vancomycin verification. This initiative could be replicated at other institutions seeking to reduce empiric vancomycin usage.

Abstract Background Revaccination is required for patients who receive a hematopoietic cell transplant (HCT) to reduce vaccine preventable illness. Revaccination requires an individualized plan due to differences in immunosuppressive therapy, immune reconstitution, age, and other challenges such as graft versus host disease. A structured approach is required to ensure prompt initiation of re-vaccinations and completion of the re-vaccination schedule. This study sought to evaluate the re-vaccination process at our center as a baseline for quality improvement. Methods We conducted a retrospective chart review of pediatric patients who received an autologous or allogeneic HCT between January 2019 and March 2024 to assess time to starting re-vaccination after post-HCT medical clearance and percentage of patients up to date within each series of vaccinations per internal protocol. Results A total of 64 patients were evaluated, of whom 23 were female and 35 underwent allogeneic stem cell transplant. For analysis, 13 were excluded due to death prior to clearance for vaccination. Among those included, 42 patients were cleared for restarting vaccines, and 37 (88%) of those have received at least one vaccine, while only 25 (59%) have completed the first series of recommended vaccines. The average time from transplant to administration of the first vaccine was 431 days for autologous HCT and 459 days for allogeneic HCT. The average time from medical clearance to the first vaccine was 66 days. The mean interval between the first and second vaccine doses was 97 days. Conclusion The majority of eligible patients initiated re-vaccination after transplant, but rates for the receipt of full recommended initial series remained suboptimal, with notable delays with notable delays between transplant and the day of clearance as well as clearance and the first vaccine administered. These findings highlight significant gaps in post-transplant immunization practices and underscore the need for targeted interventions to optimize protection for this vulnerable population. Disclosures All Authors: No reported disclosures

Background: Prophylactic antimicrobials for pediatric patients requiring extracorporeal membrane oxygenation (ECMO) support are not well delineated; there are no consistent guidelines nationally or internationally. We analyzed antimicrobial use before and after implementing a narrow-spectra ECMO antimicrobial prophylaxis protocol intended to standardize prophylaxis by risk related to ECMO type and configuration. Methods: This retrospective, single-center study included children under 18 years old requiring ECMO between May 2018 and December 2021. Medical and cardiac surgical patients requiring open-chested (central) or peripheral veno-venous or veno-arterial ECMO were included. We evaluated the impact of an ECMO antimicrobial prophylaxis protocol by comparing the appropriateness of antimicrobial use as well as nosocomial infections in the pre versus post protocol. Results: Our study included 55 children with 58 individual ECMO episodes. More than 50% of the patients were open-chested during ECMO support, and the majority of ECMO support was veno-arterial. In the post protocol period, patients were 4 times as likely to have appropriate antimicrobial prescribing (Odds ratio 4.4; 95% confidence interval: 1.1–19; P = 0.036), including both prophylactic (per protocol) and therapeutic (chart documentation of an infection with appropriate therapeutic antimicrobials, including drug and duration). There was no difference in the odds of nosocomial infection occurring during ECMO pre protocol versus post protocol (pre vs. post protocol, P = 0.71 for invasive infections, P = 0.73 for all infections including potential colonization). Conclusions: After implementation of a standardized narrow-spectra ECMO antimicrobial prophylaxis protocol, we observed an increase in appropriate and standardized antimicrobial prescribing without concomitant increase in nosocomial infections.

OBJECTIVE The optimal dose for triazoles in pediatric patients may substantially vary given the dynamic changes in pharmacokinetics and pharmacodynamics, based on disease severity. Therapeutic drug monitoring has been a valuable tool to help guide management and avoid potential toxicities associated with treatment of invasive fungal infections (IFIs). Goal azole serum concentrations are based on specific drug, indication, and minimum inhibitory concentration when known. This study aimed to determine the optimal pediatric azole doses needed to achieve targeted serum concentrations of isavuconazole, itraconazole, posaconazole, and voriconazole. METHODS This is a single center, retrospective chart review of pediatric patients who received isavuconazole, itraconazole, posaconazole, or voriconazole between January 1, 2011, and August 31, 2021. RESULTS A total of 273 pediatric patients received isavuconazole, itraconazole, posaconazole, or voriconazole in the inpatient or outpatient setting during the study period. Of the 273 patients, only 122 met criteria for inclusion in the analysis. Eighty-three percent of patients reached a goal serum concentration. Patients younger than 12 years required a higher dose (mg/kg/day) to achieve goal serum concentrations. Patients who received an azole in the form of an oral tablet or intravenously were more likely to reach a goal concentration than those not receiving these formulations. Median time to goal concentration occurred at 20 days for isavuconazole, 34 days for itraconazole, 11 days for posaconazole, and 10 days for voriconazole. CONCLUSIONS Higher starting azole doses are needed to obtain goal concentrations quickly, especially for children younger than 12 years.

ABSTRACT Background Patients at high risk for cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplant (HCT) should receive CMV prophylaxis. Historically, ganciclovir has been the preferred agent. However, its side effect profile, particularly myelosuppression, is undesirable. Letermovir is a newer agent that is not myelosuppressive and has replaced ganciclovir as the preferred agent for CMV prophylaxis in high‐risk adult patients. Methods The primary objective was to compare the incidence of dose modifications or discontinuation of CMV prophylaxis between pediatric patients who received ganciclovir versus letermovir. Secondary objectives included comparing the use of granulocyte colony‐stimulating factor (G‐CSF) support and the incidence of CMV DNAemia. We reviewed records of all pediatric patients who received an HCT at our institution between 2000 and 2024 and received either ganciclovir/valganciclovir or letermovir for CMV prophylaxis. Results Between 2000 and 2024, 65 pediatric patients receiving prophylactic ganciclovir, valganciclovir, or letermovir were evaluated. The median age at transplant was 12.2 years. No patients receiving letermovir required dose modification or discontinuation as opposed to 14 (29.2%) patients receiving ganciclovir ( p = 0.014). After engraftment, 12 (25%) patients receiving ganciclovir required G‐CSF support compared to seven (41.2%) patients receiving letermovir ( p = 0.23). In the ganciclovir group, 10 (20.8%) patients experienced CMV infection versus one (5.9%) patient receiving letermovir ( p = 0.26). Conclusion Compared with those receiving letermovir, a significantly higher proportion of patients in the ganciclovir/valganciclovir group experienced dose modifications or discontinuation of CMV prophylaxis due to adverse effects. Letermovir shows great promise as a CMV prophylactic agent in pediatric HCT patients due to its favorable side effect profile.

Abstract Background Pharmacokinetics of beta-lactams vary widely in neonatal and pediatric patients due to developmental biology and critical illness. Cefepime (FEP), meropenem (MEM), and piperacillin/tazobactam (TZP) are highly susceptible to pharmacokinetic changes as hydrophilic, small molecules with renal clearance. Subtherapeutic levels are associated with clinical and microbiologic failure, and supratherapeutic levels associated with toxicity. Beta-lactam therapeutic drug monitoring (TDM) may optimize the effectiveness and safety of these agents. The purpose of this investigation is to describe the % of pediatric and neonatal patients with beta-lactam serum levels within target range. Methods In August 2023, TDM launched at the Mayo Clinic Children’s Center for select patients treated with FEP, MEM, or TZP with expected durations ≥ 48 hours, or who were on kidney replacement therapy (KRT), extracorporeal membrane oxygenation (ECMO), weighed &gt; 120 kg, had a BMI &gt; 95th percentile, or at the discretion of pediatric ID team. Validated drug assays were performed daily, Monday through Friday. A two-level sampling strategy was preferred with a peak 1 hour after the end of the infusion and a trough 30 minutes before the next dose. Empiric trough target ranges were set at FEP 8-50 mg/L, MEM 2-30 mg/L, and piperacillin 16-150 mg/L. These target ranges were adjusted with confirmed microbiology to a time above the minimum inhibitory concentration of the organism for 100% of the dosing interval (100%T &gt; MIC). Results From August 2023 to April 2024, 74 episodes of TDM were performed on 45 patients. Thirty-seven (82%) patients were in an intensive care unit (ICU) at the time of TDM, 8/45 (22%) of whom were in the neonatal ICU. Target range was achieved in 67% of patients on FEP, 50% on MEM, and 52% on TZP. Median (IQR) trough values were 22.1 (8.6, 44.2) mg/L for FEP, 0.6 (0, 4.1) mg/L for MEM, and 15.5 (3.8, 27.1) mg/L for TZP. Seven levels were above target for FEP and 0 for MEM and TZP. Seven levels were below target for FEP, 4 for MEM, and 11 for TZP. Conclusion Implementation of a TDM program for FEP, MEM and TZP in pediatric and neonatal patients revealed drug levels frequently outside target range. TDM may facilitate dose individualization to optimize medication efficacy and minimize toxicity. Disclosures Raymond Stetson, MD, MS, Moderna: Grant/Research Support Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Board Member Erin F. Barreto, PharmD, MSc, Baxter Health: Advisor/Consultant|Wolters Kluwer: Advisor/Consultant

Abstract Background Acute hematogenous osteomyelitis (AHO) is a relatively infrequent but significant infection in pediatric patients. As Staphylococcus aureus is the most common cause of AHO, intravenous and oral first-generation cephalosporins are common therapies. Cephalexin is a commonly prescribed oral therapy for pediatric AHO, although it requires frequent dosing that may affect adherence. Cefadroxil is a comparable oral first-generation cephalosporin with a more desirable dosing schedule. Methods We reviewed pediatric patients admitted to Mayo Clinic between March 2002 and September 2020 for management of AHO who received treatment with a first-generation cephalosporin. We reviewed timing of oral therapy transition, therapy-associated adverse effects, and recurrence of disease after completion of therapy. Results There were 59 patients included in the study. There was similar occurrence of adverse effects in patients receiving cefadroxil and cephalexin, although use of cefadroxil coincided with more gastrointestinal adverse effects and leukopenia and use of cephalexin with more rash and neutropenia. One secondary treatment failure occurred in our study, in a patient receiving cephalexin for treatment of septic arthritis. Conclusions Cefadroxil may be a reasonable alternative oral therapy for methicillin-susceptible S aureus or culture-negative AHO in pediatric patients, particularly when a less frequent dosing schedule is desired. Future study with a larger sample size is warranted.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious infections and empiric treatment regimens in children frequently include an anti-MRSA antibiotic. Studies in adults have demonstrated a high negative predictive value (NPV) of MRSA nasal swabs (MNS) in a variety of infectious syndromes. Negative MNS have been utilized as a tool to guide de-escalation of anti-MRSA antibiotics in adults, especially in those with lower respiratory tract infections, but data in children is minimal. The primary objective of this study was to determine the NPV and positive predictive value (PPV) of MNS in children hospitalized for treatment of an infection. Methods: This was a single-site, retrospective cohort study of pediatric patients admitted with a suspected infectious diagnosis who had an MNS performed during their hospitalization between June 1, 2018 and November 25, 2022. Results: This study identified 172 patients who met the inclusion criteria. Eleven (6.4%) nasal swabs were positive for MRSA and 10 (5.8%) microbiological cultures from suspected sources of infection were identified to be positive for MRSA. The MNS was found to have a sensitivity of 20%, specificity of 94%, PPV of 18% and NPV of 95% for all sites of infection. Conclusion: MNS has a high NPV and low PPV in children. MNS can be utilized as an antimicrobial stewardship tool to guide the safe de-escalation of anti-MRSA antibiotics in children.

Abstract Background URIs are the most common indication for outpatient antibiotic prescribing. Given high rates of unnecessary prescribing, these indications have been identified as a high-priority target for outpatient antimicrobial stewardship programs (ASP). Our primary objective was to evaluate the impact of a system-wide, multifaceted, outpatient ASP intervention bundle on unnecessary antibiotic prescribing for URI. Methods This quasi-experimental study was conducted from 2019 to 2021. ICD-10 codes for URIs were grouped into 3 tiers (i.e., tier I = antibiotics always indicated, tier II = sometimes, tier III = never). Encounters from 5 care specialties (i.e., family medicine, community internal medicine, express care, pediatrics, and emergency department) with a tier III URI primary ICD-10 code but without a secondary tier I or tier II code were included. COVID-19 ICD-10 codes were excluded. Interventions included construction of a prescribing data model, dissemination of clinician prescribing data and education, promotion of symptom management strategies, a patient-facing commitment poster, and a pre-populated URI order panel. Tools were designed at a system level and implemented by regional champions beginning in the 3rd quarter of 2020. The primary outcome was the rate of antibiotic prescribing, and the secondary outcome and counterbalance measure was the rate of repeat URI-related healthcare contact within 14 days. Outcomes were analyzed with chi-square with an α level of 0.05. Results A total of 147403 encounters were included. The overall antibiotic prescribing rate decreased from 24.1% to 12.3% between 2019 and 2021 (p&lt; 0.01). Significant reductions in tier III antibiotic prescribing were demonstrated for each region, care specialty, and syndrome evaluated (Table 1). A reduction in repeat healthcare contact was seen across the total cohort (9.5% in 2019 vs. 8.3% in 2021, p&lt; 0.01); decreases in repeat contact rates were observed in those not initially receiving an antibiotic (10.3% vs. 8.6%, p&lt; 0.01), but not in those who initially received an antibiotic (6.8% vs. 6.8%, p = 0.94). Tier III URI encounter level antimicrobial prescribing rates by region, care specialty, and syndrome Conclusion A multifaceted, outpatient ASP intervention bundle decreased rates of unnecessary antimicrobial prescribing without increasing rates of 14-day repeat URI-related healthcare contact. Disclosures Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support Evan Draper, PharmD, Gilead Foundation: Grant/Research Support Sara Ausman, PharmD, Gilead: Honoraria Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.