Barreto, E

Introduction Community-acquired pneumonia (CAP) is common and remains the leading infectious cause of death worldwide. Antibiotics remain the mainstay of treatment, but organisms are often not identified, necessitating empirical treatment. Current treatment guidelines recommend combination therapy with beta-lactams and macrolides or monotherapy with fluoroquinolones for non-severe CAP. However, rising antibiotic resistance and safety concerns have led to increased doxycycline use, despite limited evidence supporting its efficacy. Our goal is to conduct a pragmatic, open-label, randomised clinical trial comparing the effectiveness of azithromycin with that of doxycycline in combination with beta-lactam therapy in adult patients hospitalised for CAP. Methods and analysis Patients presenting to the emergency department or directly referred to the hospital with a clinical presentation concerning for CAP and need for hospitalisation are eligible. We plan to enrol 1120 adults hospitalised at six hospitals across four states, including rural, suburban and urban settings and academic and community hospitals. Randomisation will be 1:1 using an electronic health record (EHR)-embedded screening and randomisation tool triggered by the treating clinician’s orders for azithromycin or doxycycline. Outcomes will be ascertained pragmatically via EHR-based data retrieval and will not require additional study visits. Our primary outcome is days alive and out of the hospital through day 28. Secondary outcomes include oxygen-free days; a composite of a need for advanced respiratory support or in-hospital mortality with analyses of each component separately; an ordinal measure of clinical deterioration defined by a prespecified severity scale; and 60-day and 180-day mortality. Safety outcomes are the incidence of Clostridioides difficile infection and QT prolongation. Analyses will follow an intention-to-treat framework, with per-protocol analyses for sensitivity. The primary endpoint will be compared between groups using a stratified van Elteren test, with supportive analyses using proportional odds regression and analysis of covariance adjusted for key covariates. Ethics and dissemination The Mayo Clinic Institutional Review Board reviewed and approved this protocol with a waiver of written consent, requiring verbal consent to be obtained by the clinician initiating the antibiotics (IRB# 24–0 06 503). Findings will be disseminated through peer-reviewed publications and international conference presentations. Trial registration number NCT07164131 .

Objectives: Consensus clinical criteria for refractory septic shock were recently developed, but the incidence and outcomes with these criteria are unknown. There were two aims: 1) to describe the incidence of refractory septic shock and 2) to assess outcomes of patients with septic shock meeting refractory septic shock criteria compared with those who did not. Design: Multicohort, retrospective study. For aim 1, a descriptive epidemiologic study was designed to ascertain the cumulative incidence of refractory septic shock in patients with septic shock. For aim 2, a cohort study was conducted to compare hospital mortality between patients meeting refractory septic shock clinical criteria compared with those who did not. Setting: Large U.S. health system from 2012 to 2024. Patients: Adults (age ≥ 18 yr) meeting both Centers for Disease Control and Prevention Adult Sepsis Event and Sepsis-3 clinical criteria for septic shock. Patients with missing hospital discharge disposition and incomplete vasopressor dosage information were excluded. Interventions: None. Measurements and Main Results: Clinical criteria for refractory septic shock were operationalized as concomitant occurrence of norepinephrine (base) equivalent greater than 0.5 µg/kg/min and lactate greater than 2 mmol/L. Risk-adjusted hospital mortality was assessed with a generalized linear mixed-effects model with a random effect for hospital and fixed effects for age, sex, Elixhauser Comorbidity Index, and Sequential Organ Failure Assessment (original description, without cardiovascular component). Of 35,914 patients assessed, 15,732 patients with septic shock were included. Refractory septic shock occurred in 3423 patients (21.8%), with a cumulative incidence of 218 cases (95% CI, 211–224) per 1000 patients with septic shock. Hospital mortality with refractory septic shock was 64.4%, and risk-adjusted hospital mortality odds were 4.87-fold higher (95% CI, 4.46–5.31) compared with patients without refractory septic shock. Conclusions: Clinical criteria for refractory septic shock were fulfilled in about one in five patients with septic shock and associated with substantially higher mortality.

Abstract We describe early experience with beta-lactam therapeutic drug monitoring (TDM) in a high-volume outpatient parenteral antimicrobial therapy program. In selected patients, TDM informed dose optimization and toxicity mitigation. Illustrative cases highlight feasibility and emerging lessons supporting beta-lactam TDM in outpatient care.

Abstract Rationale Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide; current guidelines recommend either the use of β-lactam therapy with a macrolide (azithromycin; AZM) or monotherapy with a fluoroquinolone for treatment. Limited evidence exists on their comparative effectiveness. To address this gap, we examined the differences in outcomes among CAP patients treated with β-lactam therapy plus AZM or fluoroquinolone monotherapymethods: We emulated a randomized clinical trial that hypothetically assigned patients to β-lactam therapy plus AZM or fluoroquinolone. Eligible patients were all adults hospitalized for nonsevere community-acquired pneumonia (CAP) based on ATS/IDSA criteria; at Mayo Clinic hospitals (3 academic and 16 community) between May 2018 and September 2022 and received one of the two treatments within 12 hours of admission. Ensemble machine learning with augmented inverse probability weighting (AIPW) was used to evaluate “intention to treat” effects on hospital-free days (HFDs), 180-day mortality, use of advanced respiratory support, in-hospital mortality, and the composite of advanced respiratory support and/or in-hospital mortality. We used the E-value and post-discharge systolic blood pressure (SBP) (negative outcome) to evaluate effects of potential unmeasured confounding and alternative “doubly robust” inverse probably weighting with regression adjustment (IPWRA) to evaluate robustness of the findings. Results 2,451 patients (2,142 β-lactam therapy plus AZM and 309 fluoroquinolone) were eligible and included in the analyses: 53.9% were female, 86.8% were White, and mean age was 58.4 years (SD: 17.02). Compared with β-lactam therapy plus AZM, the fluoroquinolone group experienced significantly higher HFD (1.50 days; 95% CI: 1.08, 1.91), lower use of advanced respiratory support (RR: 0.32; 95% CI: 0.09, 0.54), lower in-hospital mortality (RR: 0.14; 95% CI: 0.00, 0.40), and composite of advanced respiratory support and/or in-hospital mortality (RR: 0.29; 95% CI: 0.08, 0.49). Moderate to large e-values (ranging from 3.50 to 4.74) and use of negative outcomes (post-discharge SBP) suggested that unmeasured confounding is unlikely to change the findings. Sensitivity analysis using IPWRA showed very similar results. Conclusion Among hospitalized patients with non-severe CAP, treatment with fluoroquinolone monotherapy was associated with more hospital-free days, lower in-hospital mortality, and reduced need for advanced respiratory support compared with AZM and β-lactam combination. The findings highlight the role of fluoroquinolone as a beneficial alternative CAP patients. However, further studies are needed to explore the underlying mechanisms driving these differences and assess whether specific patient subgroups may benefit most from quinolone-based therapy. This abstract is funded by: none