Michael J. Durkin

Approximately 30% of U.S. outpatient antibiotic prescriptions are unnecessary. Using 2016–2022 MarketScan data, this study assessed Missouri outpatient prescribing. Among several bacterial infections, 62.4% were inappropriate; antibiotics were prescribed for 18.3% of viral infections. Inappropriate prescribing was higher in rural areas. This method can assess regional condition-specific antibiotic stewardship targets.

Objective: To evaluate antibiotic prescribing knowledge and confidence before versus after deployment of a web-based clinical decision support tool at an academic dental center. Design: Pre and post survey instrument. Setting: Academic dental center in the United States. Patients: Dental students, residents, and faculty. Methods: Participants completed a series of seven clinical vignettes assessing their antibiotic prescribing knowledge and confidence using 5-point Likert scale questions pre (2022) and post (2025) deployment of a web-based educational tool. The survey questions included content about antibiotic prophylaxis and treatment for dental infections. Mean Likert scale responses were compared before and after deployment of the tool. The responses were analyzed individually, pooled, and stratified by training level. Sensitivity analyses were conducted comparing results between tool users and non-users. Results: Two hundred and thirteen participants completed the pretool deployment survey, and 116 participants completed the post survey. Respondents were slightly less likely to prescribe antibiotics after having access to the tool (median pooled 5-point Likert Scale score 2.55 vs 2.67; P = .07). However, antibiotic prescribing confidence did not change significantly (median pooled score 3.37 vs 3.24; P = .21). Stratified results showed substantial variability based on individual vignette. Self-reported users of the tool (n = 37) demonstrated no differences in knowledge versus non-users (n = 97; P = .76) but did demonstrate a trend toward more confidence in their decisions ( P = .07). Conclusions: Uptake of a web-based antibiotic prescribing tool was low overall and was not associated with any change in antibiotic prescribing knowledge and confidence. Additional interventions are needed to improve tool use in dental settings.

Objective: We evaluated usability of a web-based clinical decision support tool designed to support antibiotic stewardship by helping clinicians differentiate asymptomatic bacteriuria from true urinary tract infections. Design: Mixed methods usability evaluation with qualitative think-aloud sessions and survey. Setting: Private academic medical center. Participants: Clinicians who evaluate and treat older adults with suspected asymptomatic bacteriuria or urinary tract infections. Methods: Participants used the tool to assess three standardized clinical scenarios, verbalizing their thoughts as they used the tool, followed by a short debrief interview and survey. Transcripts of audio recordings were analyzed using qualitative content analysis across four usability domains: navigation, content, functionality, and layout. Results: Seven clinicians (four attending physicians, three advanced practice providers) practicing in primary care, outpatient, and inpatient settings participated. The mean System Usability Score was 85.4 (SD = 10.5; range 75–100), indicating “excellent” usability. Three qualitative themes emerged: (1) positive responses to the tool’s speed, simple entry, and reassuring guidance; (2) content-related challenges, including missing symptoms, unclear fever thresholds, undefined terminology, and absent caveats for allergies, resistant organisms, or unique populations; and (3) suggested navigational changes, including links opening in new tabs, preserving entered clinical data, and reorganizing the symptom checklist. Participants highlighted electronic health record integration as necessary for sustained use. Conclusions: Participants found the tool usable and clinically valuable, particularly when infectious disease expertise is limited. Targeted refinements will be addressed before testing in a randomized study with a larger more representative sample. Future work will also pursue electronic health record integration via an embedded hyperlink for broader deployment.

Background: Antimicrobial resistance (AMR) is a growing public health threat, and we currently lack accurate measures to track and trend this resistance. We developed the antibiotic resistance index (ARI) that aggregates resistance of Gram-negative bacilli (GNB) into a single metric which can be tracked across healthcare settings and over time. Methods: Culture data were collected from adult patients who met the CDC adult sepsis event criteria across 10 Barnes-Jewish HealthCare (BJC) hospitals between January 2018 and December 2023. An antibiotic’s effective spectrum (AES) was calculated as the ratio of susceptible GNB to all identified GNB. The ARI was calculated as the sum of the AES to which the isolate was resistant. Using the 20 most common GNB and 15 most common anti-GNB antibiotics routinely tested in antibiograms, we calculated the ARI for each BJC hospital during the study years. Results: 18,854 GNB cultured from 12,803 patients meeting CDC adult sepsis event criteria were included. AES varied between 0.15 for ampicillin and 0.94 for amikacin. A. calcoaceticus-baumannii complex had the highest ARI of 6.64 (IQR 4.00–9.28). Median hospital-level ARI fluctuated between 2.12 (IQR 0.40–3.83) in 2018 to 2.20 (IQR 0.34–3.86) in 2023. The ARI trajectories over time varied by medical center. Conclusion: ARI aggregates AMR in GNB and may facilitate monitoring across locations and over time. ARI and antibiotic effective spectra redefine narrow and broad spectrum of activity and offer a starting point for antibiotic utilization metrics.

We evaluated the impact of silencing penicillin cross-reactivity alerts on perioperative antibiotic prescribing and surgical site infections (SSIs) in 6 hospitals using an interrupted time series analysis. Silencing the alerts minimally increased cefazolin prescribing among penicillin allergy labeled patients (sensitivity analysis only; P = 0.03) and had no influence on SSIs ( P = 0.32).

Purpose: Studies using insurance claims data to identify pregnancies are rarely able to directly assess the validity of the pregnancy/delivery. Inpatient versus outpatient delivery claims may provide different levels of evidence, but more stringent requirements could result in exclusion of true pregnancies. We identified delivery codes from the inpatient and outpatient settings and examined possible confirmatory evidence suggesting that a delivery truly occurred.Methods: Using a US commercial insurance database (2006–2021), we identified potential pregnancies by presence of delivery claims from a provider and/or facility. We classified deliveries as inpatient (claim date during inpatient admission) or outpatient (claim date not during inpatient admission). We identified possible confirmatory evidence for each delivery including: (1) Presence of both provider and facility delivery codes; (2) presence of both diagnosis and procedure delivery codes; (3) labor and delivery revenue codes; (4) gestational age diagnosis codes; (5) pregnancy‐related care codes; (6) linkage to an infant claim; and (7) infant insurance enrollment and linkage to a birthing parent. We quantified the proportion of deliveries with confirmatory evidence by delivery setting. Among deliveries with ≥ 1 piece of confirmatory evidence, we compared patient characteristics by apparent delivery setting.Results: Among 4 084 474 delivery episodes, 96.4% were classified as inpatient and 3.6% outpatient. 99.9% of inpatient and 94.0% of outpatient deliveries had ≥ 1 piece of confirmatory evidence. Pregnancy‐related care codes were the most common type of confirmatory evidence (99.0% inpatient, 85.7% outpatient). Deliveries classified as inpatient occurred among patients who were older and more clinically complex (i.e., more pregnancy complications, chronic diseases, and prescription medications).Conclusions: The vast majority of deliveries had confirmatory evidence regardless of apparent setting. Patient characteristics differed by delivery setting. Inclusion of apparent outpatient deliveries may increase the sample size of the study population and improve the generalizability of study results.

Background: Clostridioides difficile infection (CDI) may be misdiagnosed if testing is performed in the absence of signs or symptoms of disease. This study sought to support appropriate testing by estimating the impact of signs, symptoms, and healthcare exposures on pre-test likelihood of CDI. Methods: A panel of fifteen experts in infectious diseases participated in a modified UCLA/RAND Delphi study to estimate likelihood of CDI. Consensus, defined as agreement by >70% of panelists, was assessed via a REDCap survey. Items without consensus were discussed in a virtual meeting followed by a second survey. Results: All fifteen panelists completed both surveys (100% response rate). In the initial survey, consensus was present on 6 of 15 (40%) items related to risk of CDI. After panel discussion and clarification of questions, consensus (>70% agreement) was reached on all remaining items in the second survey. Antibiotics were identified as the primary risk factor for CDI and grouped into three categories: high-risk (likelihood ratio [LR] 7, 93% agreement among panelists in first survey), low-risk (LR 3, 87% agreement in first survey), and minimal-risk (LR 1, 71% agreement in first survey). Other major factors included new or unexplained severe diarrhea (e.g., ≥ 10 liquid bowel movements per day; LR 5, 100% agreement in second survey) and severe immunosuppression (LR 5, 87% agreement in second survey). Conclusion: Infectious disease experts concurred on the importance of signs, symptoms, and healthcare exposures for diagnosing CDI. The resulting risk estimates can be used by clinicians to optimize CDI testing and treatment.

Background: The aim of this study was to elicit clinicians’ perspectives to help reduce antibiotic prescribing for asymptomatic bacteriuria and improve a patient-centered educational brochure for older adults with urinary tract infections or asymptomatic bacteriuria. Methods: Between October 2023 and April 2024, we conducted semi-structured qualitative interviews of clinicians who treat patients aged ≥65 years for urinary tract infections or bacteria in the urine, at infectious disease clinics, community senior living facilities, memory care clinics, and general practice. We developed an interview guide based on a behavior change framework and thematically analyzed written transcripts of audio-recorded interviews using inductive and deductive coding techniques. Results: We identified several common themes surrounding management of asymptomatic bacteriuria from clinicians. These included an emphasis on ordering and interpreting urine tests, tension between guidelines and individual patient care for older adults, use of epidemiologic data to influence prescribing practices, pre-prepared communication talking points, and interest in educational materials for patients and clinical teams. Conclusions: Education about the need for symptoms to supplement urine testing, data about the impact of overuse of antibiotics, and oral and written communication strategies should be addressed to reduce antibiotic prescribing for asymptomatic bacteriuria.

Purpose: To characterize antibiotic utilization for outpatient community‐acquired pneumonia (CAP) in the United States.Methods: We conducted a cohort study among adults 18–64 years diagnosed with outpatient CAP and a same‐day guideline‐recommended oral antibiotic fill in the MarketScan® Commercial Database (2008–2019). We excluded patients coded for chronic lung disease or immunosuppressive disease; recent hospitalization or frequent healthcare exposure (e.g., home wound care, patients with cancer); recent antibiotics; or recent infection. We characterized utilization of broad‐spectrum antibiotics (respiratory fluoroquinolone, β‐lactam + macrolide, β‐lactam + doxycycline) versus narrow‐spectrum antibiotics (macrolide, doxycycline) overall and by patient‐ and provider‐level characteristics. Per 2007 IDSA/ATS guidelines, we stratified analyses by otherwise healthy patients and patients with comorbidities (coded for diabetes; chronic heart, liver, or renal disease; etc.).Results: Among 263 914 otherwise healthy CAP patients, 35% received broad‐spectrum antibiotics (not recommended); among 37 161 CAP patients with comorbidities, 44% received broad‐spectrum antibiotics (recommended). Ten‐day antibiotic treatment durations were the most common for all antibiotic classes except macrolides. From 2008 to 2019, broad‐spectrum antibiotic use substantially decreased from 45% to 19% in otherwise healthy patients (average annual percentage change [AAPC], −7.5% [95% CI −9.2%, −5.9%]), and from 55% to 29% in patients with comorbidities (AAPC, −5.8% [95% CI −8.8%, −2.6%]). In subgroup analyses, broad‐spectrum antibiotic use varied by age, geographic region, provider specialty, and provider location.Conclusions: Real‐world use of broad‐spectrum antibiotics for outpatient CAP declined over time but remained common, irrespective of comorbidity status. Prolonged duration of therapy was common. Antimicrobial stewardship is needed to aid selection according to comorbidity status and to promote shorter courses.

Objective: To explore older adults’ and caregivers’ knowledge and perceptions of guidelines for appropriate antibiotics use for bacteria in the urine. Design: Semi-structured qualitative interviews. Setting: Infectious disease clinics, community senior living facilities, memory care clinics, and general public. Participants: Patients 65 years or older diagnosed with a urinary tract infection (UTI) in the past two years, or caregivers of such patients. Methods: We conducted interviews between March and July 2023. We developed an interview guide based on the COM-B (capability, opportunity, motivation-behavior) behavior change framework. We thematically analyzed written transcripts of audio-recorded interviews using inductive and deductive coding techniques. Results: Thirty participants (21 patients, 9 caregivers) enrolled. Most participants understood UTI symptoms such as pain during urination and frequent urination. However, communication with multiple clinicians, misinformation, and unclear symptoms that overlapped with other health issues clouded their understanding of asymptomatic bacteriuria (ASB) and UTIs. Some participants worried that clinicians would be dismissive of symptoms if they suggested a diagnosis of ASB without prescribing antibiotics. Many participants felt that the benefits of taking antibiotics for ASB outweighed harms, though some mentioned fears of personal antibiotic resistance if taking unnecessary antibiotics. No participants mentioned the public health impact of potential antibiotic resistance. Most participants trusted information from clinicians over brochures or websites but wanted to review information after clinical conversations. Conclusion: Clinician-focused interventions to reduce antibiotic use for ASB should also address patient concerns during clinical visits, and provide standardized high-quality educational materials at the end of the visit.