Objective:The aim was to describe the development and implementation of Firstline (www.Firstline.org), a mobile antimicrobial stewardship (ASP) application (app) created to address barriers to robust ASP in Colorado hospitals. Design:A mixed-methods pragmatic implementation study using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework was conducted from October 2023-December 2025. Methods:ASP teams at Children's Hospital Colorado and Denver Health partnered with Firstline to develop the app using locally curated content. The app launched in October 2023 with a multifaceted dissemination campaign. Reach was assessed using geocoded user data. Effectiveness and adoption were evaluated using cross-sectional surveys at two time points. Implementation was characterized by analyzing utilization patterns. Maintenance was assessed by tracking monthly active users over two years. Results:Within the first year, 4,409 unique Colorado users downloaded the app, representing 15% of state clinicians (19% in Denver Metro; 5-17% in rural regions). Survey respondents (n = 215) reported high satisfaction: 63.9% and 72.9% found the app very easy to use, 71.3% and 83.2% reported enhanced antibiotic selection knowledge, and 100% advocated for ongoing support. Among respondents, 10% reported their facilities had formally adopted Firstline guidelines. The most frequently accessed content included common, high-impact infections. Monthly active users remained stable (average 871) over two years. Conclusions:We demonstrated use of Firstline across Colorado, with increasing engagement in rural areas. High user satisfaction, sustained engagement, and emerging institutional adoption suggest this "stewardship in your pocket" model offers a unique, scalable approach to extending ASP support beyond academic medical centers.

CDC Core Elements of Hospital Antibiotic Stewardship (AS) and national accreditation bodies prioritize the implementation of facility-specific treatment recommendations and monitoring of adherence to those recommendations. These activities are a challenge for resource-limited hospitals, which we sought to overcome with the Colorado Antimicrobial Resources, Education, and Pathway Adherence Tools for Hospitals (CARE PATH) initiative. Here we report interim findings.Table 1:Adherence RatesBreakdown of adherence rates to clinical pathways by hospital typeFigure 1:Local vs Firstline Pathway Adherence Rates Quarters 1 and 2 by Facility TypeGraphic representation of pathway adherence rates by disease state, pathway type, and facility type Children’s Hospital Colorado, in partnership with Denver Health, created a free mobile application using Firstline (Firstline.org) to share evidence-based clinical pathways across Colorado, which could be adapted for use as facility-specific treatment recommendations. From July 2024-March 2025 hospitals voluntarily submitted antibiotic use data for cases of pediatric or adult community acquired pneumonia (CAP), urinary tract infection (UTI), and/or skin/soft tissue infection (SSTI) via a web-based REDCap survey. AS experts assessed prescribing compared to local clinical pathways (LCPs) and Firstline. LCP adherence was based on self-report of antibiotic selection. Firstline adherence was met if 3 criteria were consistent with app recommendations: antibiotic selection, treatment duration, and clinical indication. Facilities received quarterly reports with feedback and recommendations for AS. To supplement the reports, our team hosted a series of interactive webinars and 1-on-1 mentorship sessions. 26 facilities registered for CARE PATH, 11 critical access (42%) and 15 acute care (58%). 22 (85%) reported having a local adult or pediatric CAP pathway, 21 (81%) a UTI, and 21 (81%) a SSTI LCP. 12 (46%) did not monitor adherence prior to CARE PATH. 13 (50%) facilities reported data on at least one condition in quarter 1, and 8 (30%) for quarter 2. Adherence rates to LCPs and Firstline are presented in Table 1 and Figure 1. CARE PATH has helped 13 Colorado hospitals meet priority core elements. Adherence rates varied, with SSTI the lowest. CAP adherence increased Q1 to Q2, though UTI and SSTI changes were variable. These findings represent a novel hospital-state health collaboration and inform state-wide antimicrobial stewardship efforts. Leigh Anne Bakel, MD, Colorado Department of Public Health and Environment: Grant/Research Support|Pfizer: Grant/Research Support Sarah K. Parker, MD, Colorado Department of Health and Environment: Advisor/Consultant|Infectious Diseases Society of America: Reimbursement for Program Committee|Pfizer Global Bridges: Grant/Research Support|Society for Healthcare Epidemiology of America: Honoraria|Society of Infectious Diseases Pharmacists: Honoraria

BACKGROUND AND OBJECTIVES:Staphylococcus aureus is the most common causative pathogen for children with acute hematogenous osteomyelitis (AHO) and acute bacterial arthritis (ABA). National guidelines recommend empiric coverage for methicillin-resistant S. aureus (MRSA) at hospitals where the overall MRSA rate is greater than 10% to 20%. The objective of this study was to evaluate the frequency and appropriateness of empiric MRSA coverage for AHO and ABA among hospitalized children in the United States. METHODS:Hospital encounters from September 2015 through December 2024 for AHO and ABA were identified using the Pediatric Health Information System (PHIS) database and were categorized based on validated, pathogen-specific discharge codes. Hospital-specific rates of methicillin resistance among all S. aureus isolates were collected directly from participating PHIS hospital antibiograms. RESULTS:A total of 15 841 hospitalizations from 46 PHIS hospitals were included. Among the 48% of children with a pathogen-specific discharge code assigned, 17% were MRSA. Most children without MRSA identified (58%) received empiric MRSA antimicrobial therapy. Most hospital antibiograms had an MRSA rate above 20%, although the rate of MRSA for AHO and ABA was consistently less than hospital-wide MRSA rates. Across all PHIS hospitals, the MRSA rate for AHO and ABA was half that of hospital-wide MRSA rates (0.5; range, 0.2-1.17). CONCLUSIONS:Most children hospitalized in the United States for AHO and ABA receive empiric MRSA therapy, although few have MRSA identified. Hospital-wide antibiograms consistently have a higher MRSA rate than seen in patients with AHO and ABA, and development of AHO- and ABA-specific antibiograms may improve targeted empiric therapy for children with osteoarticular infections.

Advancement of antimicrobial stewardship (AS) programs requires partnership with clinicians, quality assurance teams, and laboratorians. Inevitably, AS programs also practice diagnostic stewardship (DS), as stewards are aptly placed to connect key stakeholders and help steer processes toward higher value care for pediatric patients. In this review, we illustrate five moments of collaboration between stakeholders in the interplay between AS and DS in pediatrics. These moments include (1) Observation, (2) Reflection, (3) Exploration, (4) Enactment and (5) Evaluation. We offer a targeted narrative of examples in current literature using common relatable scenarios (ie, endotracheal aspirates, blood cultures, gastrointestinal samples, and urine testing) including impact on financial and environmental waste.

Administrative databases are powerful tools for pediatric research but lack patient-level microbiology results. This study aimed to determine the accuracy of pathogen discharge diagnosis codes for children hospitalized with acute hematogenous musculoskeletal infections (MSKIs). Medical records for 244 children hospitalized with acute hematogenous MSKIs were manually reviewed to determine which bacterial pathogen, if any, was identified for each MSKI based on microbiology results obtained during the hospitalization. Microbiology results for each patient were then compared to their discharge diagnoses in the Pediatric Health Information System (PHIS) database to determine the accuracy of pathogen discharge codes. Discharge diagnostic codes correctly matched the microbiology results in 89.3% of encounters. Sensitivity and specificity for Staphylococcus aureus discharge diagnostic codes were 88.6% and 96.4% respectively for methicillin-susceptible S. aureus and 92.9% and 99.5% for methicillin-resistant S. aureus. Pathogen discharge codes are reliable surrogates that accurately reflect the microbiology results for children with MSKIs.

Abstract Background Several barriers to antimicrobial stewardship (ASP) in various Colorado hospitals were previously identified, including lack of clinical pathways, antibiotic dosing knowledge in neonatal and pediatric populations, and understanding of stewardship methodologies. We sought to mitigate barriers to robust ASP in Colorado hospitals through creation of a mobile application decision support system, Firstline (www.Firstline.org). Our objective is to describe the uptake, usage patterns, and satisfaction of Firstline across the state. Figure 1 Run chart of monthly active users of the Children’s Colorado and Denver Health Firstline app from beginning of November 2023 through end of April 2024. Methods ASP teams at Children’s Hospital Colorado (CHCO) and Denver Health (DH) partnered with Firstline to develop the app with locally curated content including: 1) CHCO and DH clinical pathways, 2) pathogen information, 3) antimicrobial information, and 4) infection prevention and ASP resources. The CHCO platform went live October 10th, 2023, and DH on October 31st, 2023. Firstline provided analytic data on the number of users and usage patterns. The CHCO Physician Relations team and the Colorado Department of Regulatory Agencies (DORA) Professional and Occupational Licenses Information Marketplace provided Practitioner data. Feedback on the app was obtained via a REDCap survey distributed through Firstline. Figure 2 Run chart of monthly active users of the Children’s Colorado and Denver Health Firstline app from beginning of November 2023 through end of April 2024. Results A total of 3,287 unique mobile users accessed CHCO or DH Firstline from launch through April 2024. There were 718 average monthly active users (Figure 1). In total, 13% of Colorado practitioners from all regions accessed Firstline through April 2024 (Figure 2). Over 60% of survey responders used the app daily or weekly, and found the app very easy to use. Support with antimicrobial choice or dosing was the most common reason for using the app. The majority of survey responders noticed a positive enhancement in antibiotic selection, dosing, and guideline utilization through use of the app. 100% of respondents advocated for ongoing support of Firstline (Table 1). Table 1 Table of cumulative responses from the REDCap Firstline satisfaction survey. ASP, Antimicrobial Stewardship Program; IP, Infection Prevention. Conclusion We disseminated a mobile application support tool to augment ASP in Colorado with positive initial feedback. Widespread dissemination to rural communities in Colorado is ongoing. Future work includes assessing the impact of the app on antimicrobial utilization, guideline adherence, and implementation of priority core CDC elements for ASP. Disclosures Sarah K. Parker, MD, Colorado Department of Health and Environment: Advisor/Consultant|Pfizer Global Bridges: Grant/Research Support

Background: Antibiotics are frequently prescribed in the NICU, with increasing concern for antimicrobial resistance. Time to positivity (TTP) of positive cultures can support earlier antimicrobial cessation. Methods: Retrospective cohort study all positive blood cultures at a Level IV NICU. TTP calculated from date/time collection to when first growth was reported. Results: Of 309 positive cultures from 268 infants, median TTP [IQR] was 21.1 [14.3, 25.2] hours, with 91.2% positive at 36 hours, and 96.1% positive at 48 hours. 77 gram positive pathogens (24.9%), 60 gram negative pathogens (19.4%), and 169 gram positive commensals identified, with 124 (40.1%) considered a contaminant. Sub-group analysis identified different organism characteristics. Death within 4 weeks of positivity recorded in 9.5%. Conclusion: Majority of gram positive and negative pathogens were identified within 36h of blood culture collection. When antimicrobials are started for concern for bacteremia, 36 hours may be sufficient in a Level IV NICU population.

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Abstract Corresponding Author: Sarah K. Parker, MD, Professor, Department of Pediatrics, Section of Infectious Diseases; Children’s Hospital Colorado and University of Colorado School of Medicine; 13123 E 16th Ave, Box B055, Aurora, CO 80045; sarah.parker@childrenscolorado.org; 720-777-8811 Alternate Corresponding Author: Matthew J. Weber, MPH, Department of Pediatrics, Section of Infectious Diseases; Children’s Hospital Colorado and University of Colorado School of Medicine; 13123 E 16th Ave, Box B055, Aurora, CO 80045; matthew.weber@childrenscolorado.org; 720-777-8811 Conflicts of interest/disclosures: Grant from Pfizer Global Bridges to SKP, Contract with Colorado Department of Health and Environment to SKP, both to improve antimicrobial stewardship in the state of Colorado, and do not support this work. Background Children’s Hospital Colorado began a Handshake Stewardship program in 2013 that effectively decreased hospital anti-infective use and costs (~$2 million per year) in its pilot year (Hurst et al, PIDJ, 2016; Parker et al, CID, 2017), and continued to improve use over the next 5 years (MacBrayne et. al, CID, 2019). Handshake stewardship is distinguished by: (1) lack of prior authorization; (2) a review of all prescribed anti-infectives; (3) a shared review by the physician and the pharmacist; and (4) a daily, rounding-based, in-person approach to support providers. We sought to reevaluate outcomes after a decade of Handshake Stewardship. Methods We retrospectively measured anti-infective (antibiotic, antiviral, antifungal) use hospital-wide by unit and by drug for a 13-year period spanning October 2010 to March 2024; October 2010 to September 2011 was the pre-period without stewardship, and October 2011 to September 2013 the planning period. Handshake Stewardship started in October of 2013. Aggregated monthly use was measured in days of therapy per thousand patient days (DOT/1000 PD). Children’s Hospital Colorado antibiotic DOT was validated using the Children’s Hospital Association Pediatric Health Information System (PHIS) Antimicrobial Stewardship Dashboard annual reports of Standardized Antimicrobial Administration Ratio (SAAR) antibacterials, DOT/1000 PD for 2016-2023. Results Hospital-wide mean anti-infective use continues to decrease. Analysis of DOT for the time period demonstrate averages 1060 DOT/1000 PD pre stewardship, 902 DOT/1000 PD post initiation of Handshake Stewardship, and 718 DOT/1000 PD for 2020 to March 2024 (p<0.001, Fig. 1). Children’s Hospital Colorado SAAR antibiotic DOT was 820 DOT/1000 PD pre stewardship, 701 DOT/1000 PD post initiation of Handshake Stewardship, and 525 DOT/1000 PD for 2020 to March 2024 (p<0.001, Fig. 1). These data confirmed in PHIS for the accessible time period of 2016-March 2024. Decreases were observed in almost all units, except the cardiac intensive care unit, and with almost all commonly used anti-infectives. MRSA agents and gram-negative agents decreased over time; use of those agents and overall use were low compared to peer PHIS hospitals. Conclusions Handshake Stewardship continues to demonstrate improvements in anti-infective use, albeit at a slower rate. As the program has matured, incremental gains are fostered by this methodology, likely driven by stewardship targeting pathway revisions and dissemination, diagnostic stewardship initiatives, and quality initiatives, like antibiotic durations, etc. Areas for focus also emerged, and initiatives are underway. In-depth analysis and formal statistical evaluation are planned. Figure: Days of therapy per 1000 patient days for all inpatient units. Anti-infective rate includes all antibiotics, antivirals, and antifungals. Antibiotic rate includes SAAR reported antibacterials.

Clinical metrics of baseline health in sentinel seabird species can offer insight into marine ecosystem dynamics, individual and population health, and assist in wildlife rehabilitation and conservation efforts. Protein electrophoresis is useful for detecting changes in acute phase proteins and immunoglobulin levels that may indicate subtle inflammatory responses and/or infectious disease. Serum biochemistry can highlight nutritional status, metabolic derangements, and organ injury and function. However, baseline values for such health parameters are largely unknown for many seabird species. Therefore, the objective of this study is to establish baseline clinical health reference intervals for serum protein electrophoresis, acute phase proteins including serum amyloid A and haptoglobin, and biochemistry parameters in the rhinoceros auklet (Cerorhinca monocerata), a key sentinel species in the North Pacific. From 2013 to 2019, 178 wild, apparently healthy breeding adult rhinoceros auklets were captured across four breeding colonies in British Columbia, Canada (Lucy Island, Pine Island, Triangle Islands, and SGang Gwaay) and from one colony in Washington, United States (Protection Island). Reference intervals were calculated for protein electrophoresis fractions and acute phase proteins (n = 163), and serum biochemistry (n = 35) following established guidelines by the American Society of Veterinary Clinical Pathology. Animals were also assessed for the presence of antibodies to the influenza A virus. Approximately 48% (70/147) of sampled birds were seropositive for influenza A virus, with a prevalence of 50% (6/12) in 2013, 75% (47/63) in 2014, and 24% (17/72) in 2019. This work provides clinical baseline health metrics of a key North Pacific sentinel species to help inform marine ecosystem monitoring, recovery, and rehabilitation efforts in the Pacific Northwest.

Positive emotions can reduce disease susceptibility during infectious challenges in humans, and emerging evidence suggests similar effects in farm animals. Because play behaviour may support a positive emotional state in pigs, this study investigates whether rearing pigs with regular intermittent play opportunities enhances disease resilience when challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Litters were assigned to either play (PLY; n = 5 L) or control (CON; n = 4 L) treatments at birth. In PLY, play was promoted with extra space and enrichment items for three hours daily from five days of age (doa). At weaning (25 ± 2 doa; mean ± SD), 28 pigs (14/treatment) were selected for a disease challenge, based on weight, sex, and sow. The pigs were transported to a disease containment facility and at 43 ± 2 doa (day 0 post-inoculation, DPI) inoculated with PRRSV. Skin lesions, blood, rectal temperature, clinical signs, body weight, and behaviour were collected pre- and post-inoculation. Play opportunities for PLY continued every other day until euthanasia of all pigs at 65 ± 2 doa (22 DPI). PLY pigs exhibited fewer skin lesions following transport and throughout the infection compared to CON. Although the viral load did not differ between treatments, PLY pigs had a lower probability of experiencing moderate and severe respiratory distress, with a shorter duration. PLY also performed better throughout the infection, showing higher ADG and greater feed efficiency. The immune response differed as well. PLY pigs had fewer monocytes on 8 DPI than CON, with levels returning to baseline by 21 DPI, whereas CON levels exceeded baseline. Regardless of day of infection, lymphocyte counts tended to be lower in PLY than in CON, and white blood cells and neutrophils were also lower, but only in slow-growing pigs. PLY pigs continued to play during the infection, demonstrating less sickness behaviour and emphasizing the rewarding properties of play. Results suggest that PLY pigs were less affected by PRRSV and developed increased resilience to PRRSV compared to CON. This study demonstrates that rearing pigs in an environment supporting positive experiences through provision of play opportunities can enhance resilience against common modern production challenges, underscoring the value of positive welfare in intensive pig farming.

Cannabis use among young adults (YAs) 18-25 years is at the highest level in 20 years; almost 5 million YAs have cannabis use disorder (CUD). YAs with CUD, especially those of racial/ethnic minorities and lower income, face numerous barriers to treatment. To improve treatment access, we developed a virtual form of a counseling-plus-mhealth intervention, Momentary Self-Monitoring and Feedback + Motivational Enhancement Therapy (MOMENT-V). This open pilot preliminarily evaluated satisfaction and engagement with MOMENT-V. Patients of an urban adolescent/young adult practice self-screened via QR code on clinic postings, patient portal invitation, and/or provider invitation. Eligibility included age 18-25 years, primary care patient, past-30-day recreational cannabis use >3 days/week, ability to read/speak English, and smartphone ownership; patients could not be certified for medical cannabis use or in a substance use treatment program. All participants were assigned MOMENT-V: two ∼45-minute telehealth Motivational Enhancement Therapy (MET) sessions one week apart with a counselor, followed by two weeks of mobile phone surveys (4/day) querying momentary socioemotional contexts and cannabis use, with pre-programmed messages after report of personal triggers for use (Ecological Momentary Intervention; EMI). Participants completed an electronic survey on cannabis use-related factors and an interview-administered timeline follow-back (TLFB) calendar on substance use at baseline and post-intervention. Satisfaction was assessed following each MET session and the EMI using electronic surveys on counselor rapport, session activities, phone surveys and messages, technical issues, burden, and usefulness. EMI engagement was calculated as % days with ≥1 phone survey completed. Free text about favorite and least favorite parts of MOMENT-V was recorded. In 6 months, 43 patients self-screened, 20 were eligible (47%), and 14 enrolled (70% of eligible). Mean age was 22.1 years. Most participants (86%) were female and most (82%) reported Black race, non-Hispanic ethnicity. Most participants (79%) reported using cannabis daily/near-daily (median 30 of 30 days, interquartile range [IQR] 20-30); 93% (13/14) met CUD criteria. All participants (100%) completed both MET sessions and responded to EMI surveys. Satisfaction with the MET was high. All participants agreed or strongly agreed that they felt respected by, comfortable with, and trust for the counselor and that they found the activities and discussion helpful; 100% rated the MET sessions very good or excellent. Technical issues were minor and infrequent (MET – video froze or audio lagged, 25% of sessions; EMI – app or survey completion problems, 2 participants). No participant indicated that they disliked completing the EMI surveys. Median EMI engagement was 96% (IQR 66%-100%). No participant endorsed that the study was burdensome. All participants rated overall intervention quality good, very good, or excellent. In general, participants' favorite part related to the MET and least favorite part related to the EMI. Novel approaches to effective intervention are urgently needed for the underserved population of YAs with CUD. In this pilot study, YAs were highly satisfied and engaged with a telehealth MET counseling-plus-mobile health EMI intervention for cannabis use. A randomized trial to further evaluate the feasibility and determine the efficacy of MOMENT-V is warranted.

The provision of opportunities to express rewarding behaviours is a promising concept to support a better quality of life for intensively farmed pigs. Play behaviour has been associated with excitement and fun, suggesting that playing animals experience pleasurable states. Pigs play intensively between 2 to 6 weeks of age and this decreases with age thereafter. To determine if the provision of play opportunities could enhance the quality of life of pigs, this study investigated if play can be promoted and sustained in pigs beyond the natural period of expression in a commercial setting. Whether play is positive for pigs and the effect of play on average daily gain and stress physiology was also explored. Growing pigs (n = 288, 10 weeks of age), housed in standard partly-slatted pens, were assigned to either a Control treatment with no play interventions (CON, 1 m2/pig); or to a Novelty (NOV) or Play pen (PLP) treatment, with play promotion between 10 to 21 weeks delivered through play sessions 3x/week. Play treatments received the intermittent provision of destructible novel objects provided either in the home pen (NOV, 1 m2/pig), or in an enclosed ‘play pen' area providing extra space (PLP, 2.9 m2/pig). To understand if play is positive, the frequency and duration of anticipatory behaviour were recorded before play sessions, whilst play behaviour, along with indicators of emotional valence such as vocalization, tail, and ear postures, were recorded during play sessions on focal pigs (n = 144) at 11, 16 and 21 weeks. To explore the physiological response to play, saliva was collected pre and post play, and analysed for cortisol and alpha-amylase, and growth rate was calculated from trial entry and exit weights. Pigs in PLP and NOV played more frequently (p = 0.002) and for a longer duration of time (p < 0.001) across weeks compared to CON. NOV and PLP did not differ in play frequency and duration, except for week 21 when PLP played more frequently. Play treatments expressed more anticipatory behaviour and behavioural indicators associated with a positive experience (ears relaxed and forward, tail wagging, barks) compared to CON. Cortisol was elevated only in NOV compared to CON after the play session, but alpha-amylase and growth rate did not differ. Play was successfully promoted and sustained until the finishing period and equally expressed regardless of extra space. Pigs with play opportunities expressed indicators that play is a rewarding and motivating behaviour and could enhance the quality of life of farmed pigs when supported.

Background Acute otitis media (AOM) is the most common reason children are prescribed antibiotics. Bacteria that produce beta-lactamase are an increasingly frequent cause of AOM and may be resistant to amoxicillin, the currently recommended treatment for AOM. We aimed to evaluate the clinical outcomes of children treated with amoxicillin for AOM and assessed whether outcomes vary by infecting pathogen or beta-lactamase production.Methods 205 children 6-35 months old diagnosed with AOM and prescribed amoxicillin were included. Bacterial culture and qualitative multiplex real-time polymerase chain reaction were performed on nasopharyngeal swabs collected at enrollment. Parents completed surveys assessing symptoms, antibiotic adherence, and potential adverse events. The primary outcome was treatment failure with amoxicillin. Secondary outcomes included recurrence, symptom improvement, resolution, and adverse drug events (ADE).Results 8 children (5.4%) experienced treatment failure and 14 (6.8%) had recurrence. By day 5, 152 (74.1%) children had symptom improvement and 97 (47.3%) had resolution. Parents reported ADE for 56 (27.3%) children. Among 149 children who did not take any amoxicillin before enrollment, 98 (65.8%) had one or more beta-lactamase-producing bacteria. Common bacterial otopathogens were Moraxella catarrhalis (79, 53.0%), Streptococcus pneumoniae (51, 34.2%), Haemophilus influenzae (30, 20.1%), and Staphylococcus aureus (21, 14.1%). Treatment failure did not differ between children that did (5, 5.1%) and did not (3, 5.9%) have beta-lactamase-producing otopathogens (p = .05).Conclusions Among children diagnosed with AOM treated with amoxicillin, treatment failure was uncommon and did not differ by pathogen or beta-lactamase production. These data support guidance recommending amoxicillin despite an increasing prevalence of beta-lactamase-producing bacteria. Among children treated with amoxicillin for acute otitis media, treatment failure was uncommon and did not differ based on the associated pathogen or beta-lactamase production.

INTRODUCTION:To improve treatment access for emerging adults with cannabis use disorder (CUD), we developed a telehealth counseling-plus-mHealth intervention and remotely conducted a single-arm open pilot study to preliminarily evaluate its feasibility in primary care. METHODS:A multidisciplinary team including youth developed the intervention using the structure of the MOMENT intervention: two weekly counselor-delivered Motivational Enhancement Therapy (MET) sessions, then two weeks of smartphone surveys (4 prompted/day) querying socioemotional contexts and cannabis use, with pre-programmed messages on report of personal triggers for use (Ecological Momentary Intervention; EMI). The team adapted the MET for virtual delivery; created material to enhance self-reflection, plan behavior change, and anticipate withdrawal; shortened the sessions; and tested them with five youth actors. EMI messages were created to align with the MET and programmed to minimize repetition. Patients aged 18-25 using recreational cannabis ≥3 days/week were recruited from an urban medical practice. Participants received the intervention and responded to surveys on satisfaction and burden. At baseline, post-intervention, and two months, participants reported behavior change readiness/importance/confidence and cannabis use. EMI engagement was calculated as % days with ≥1 phone survey completed. RESULTS:Fourteen eligible patients enrolled; 79 % used cannabis daily/near-daily and 100 % reported use problems. All completed both MET sessions and responded to EMI surveys. All agreed/strongly agreed that they felt respected by, comfortable with, and trust for the counselor and that the activities and discussion were helpful; all rated the MET sessions as very good/excellent. Technical issues were infrequent and minor. Median EMI engagement was 100 % (≥1 report/day) in each week. Behavior change confidence was higher post-intervention and importance and confidence were higher at two months vs. baseline. By two months, 11 participants had started to change cannabis use; median percent days of use in the past 30 days declined by 27 % and average times of use per use day declined by 28 %. All rated intervention quality as good, very good, or excellent. CONCLUSIONS:Emerging adults were highly satisfied and engaged with a telehealth MET counseling-plus-mHealth EMI intervention for cannabis use and reported higher motivation to change cannabis use and less use post-intervention and at 2-month follow-up.

Abstract Corresponding Author: Joana Dimo, DO, Department of Pediatrics, Division of Infectious Diseases, University of Colorado, 13123 East 16th Avenue, Box 055, Aurora, CO 80045, USA. 216-210-4687, joana.dimo@childrenscolorado.org Alternate Corresponding Author: Sarah K Parker, MD, Department of Pediatrics, Division of Infectious Diseases, University of Colorado, 13123 East 16th Avenue, Box 055, Aurora, CO 80045, USA, (720) 777-8811, sarah.parker@childrenscolorado.org Funding: This work was supported by the Pfizer Global Medical Grants and Global Bridges at Mayo Clinic (grant number 70956251) and through a contract with the Colorado Department of Public Health and Environment (CDPHE). No conflicts of interest Background Previous collaborative work with Children’s Hospital Colorado (Children’s Colorado) and the Colorado Department of Public Health and Environment (CDPHE) uncovered several self-identified barriers to antimicrobial stewardship (ASP) in various Colorado hospitals (n=100), with the most significant being lack of clinical pathways, lack of antibiotic dosing knowledge in the neonatal and pediatric populations, and lack of understanding of stewardship methodologies. We sought to mitigate barriers to robust ASP among Colorado hospitals through implementation and dissemination of a mobile application decision support system, Firstline ( www.Firstline.org ). Our objective is to describe the uptake and usage patterns of Firstline across the state. Methods ASP teams at Children’s Colorado and Denver Health partnered with Firstline to develop the mobile application. Children’s Colorado and Denver Health teams provided neonatal/pediatric and adult guidance respectively. Content featured in the app includes, 1) facility-specific clinical pathways, 2) pathogen information, 3) antimicrobial dosing and monitoring, and 4) infection prevention and ASP resources. The Children’s Colorado platform went live October 10th, 2023, and Denver Health on October 31st, 2023. Firstline provided analytic data on the number of users and usage patterns. The Children’s Colorado Physician Relations team (data from Definitive Healthcare Database) and the Colorado Department of Regulatory Agencies (DORA) Professional and Occupational Licenses Information Marketplace provided Practitioner data. Results 3287 total unique mobile users accessed Children’s Colorado or Denver Health Firstline from launch through end of April 2024. There were 718 average monthly active users (Figure 1), primarily physicians in an inpatient setting, and mainly located at Children’s Colorado. In total, 13% of Colorado practitioners from all regions were shown to have accessed Firstline (Figure 2), with 7% of all Firstline users located outside of the Denver Metro area. Conclusion We disseminated a mobile application support tool to augment ASP in Colorado, with the greatest uptake in the Denver Metro area. Widespread dissemination to more rural communities in Colorado is ongoing. Future work includes assessing the impact of the application on antimicrobial utilization, clinical guideline adherence, and implementation of priority core ASP elements. Figure 1: Run chart of monthly active users of the Children’s Colorado and Denver Health Firstline app from beginning of November 2023 through end of April 2024. Figure 2: Proportion of Firstline users per all practitioners throughout Colorado regions. Image modified from OnTheWorldMap.com.