Citations

ABSTRACT Serine–aspartate repeat-containing protein D (SdrD) is a Staphylococcus aureus cell wall–anchored, calcium-binding adhesin member of the MSCRAMM Sdr subfamily that may contribute to bacterial adhesion and virulence. S. aureus is the most common cause of periprosthetic joint infection (PJI). Population-level distribution and sequence diversity of SdrD among clinical PJI isolates have not been systematically characterized, and the SdrD binding mechanism is still not well understood. To address these gaps, sdrD alleles were queried across 156 newly sequenced PJI isolates and compared to publicly available S. aureus genomes, and nucleotide– and protein-level phylogenies of the sdrCDE locus constructed. The SdrD crystal structure from S. aureus JH1 was determined, with solution small-angle X-ray scattering (SAXS) and molecular dynamics (MD) simulations, and assessment of conformational changes with calcium depletion. Three dominant sdrD subtypes were defined, associating with USA300, JH1, and TCH60; the JH1 sdrD subtype was predominant among PJI isolates. Structural studies showed that the conformation of individual domains and interdomain organization of the multidomain SdrD have limited flexibility in solution, and that the calcium-binding B domain retains its core fold under conditions of calcium depletion. Together, the findings presented support functional diversification among Sdr family members in mediating host attachment and inform a re-evaluation of the ligand-binding mechanism previously proposed for SdrD. AUTHOR SUMMARY Staphylococcus aureus is the leading cause of infections that develop around joint implants (periprosthetic joint infection, PJI). This bacterium has a large arsenal of surface proteins that allow it to stick to human tissues and implanted devices. This work focused on one such protein, SdrD, which has been linked to implant-associated infections but the structure and diversity of which among patients with PJI had not been well characterized. The genetic sequences of SdrD were analyzed across thousands of bacterial genomes, including those from patients with PJI. Distinct genetic variants of the protein were found, one of which was particularly common with PJI. The three-dimensional structure of SdrD was determined at atomic resolution and solution small-angle X-ray scattering (SAXS) and molecular dynamics used to study how it moves and responds to changes in its environment. Contrary to what was previously described, SdrD was shown to be relatively rigid. These findings change how SdrD’s mechanism of action should be considered, potentially informing design strategies to block bacterial attachment before infection takes hold.

Abstract Both the phase 3 MAIA and ALCYONE studies demonstrated significant survival benefit with the addition of daratumumab to standard-of-care Rd (Revlimid [lenalidomide] and dexamethasone; D-Rd) or to VMP (Velcade [bortezomib], melphalan, and prednisone; D-VMP), respectively, vs Rd or VMP alone in transplant-ineligible newly diagnosed multiple myeloma (NDMM). Patients with NDMM are highly susceptible to infection; therefore, gaining a greater understanding of infection incidence may help to mitigate future risk. We conducted a pooled analysis of infection incidence, timing, and management strategies from MAIA and ALCYONE. The median (range) age of the pooled population was 72 (40-93) years. Incidence was higher with D-Rd/D-VMP vs Rd/VMP for grade 3/4 (36.9% vs 22.4%) and grade 5 (3.0% vs 1.5%) infections; however, exposure-adjusted incidence rates were generally comparable between groups. Any-grade infections led to the discontinuation of study treatment in ∼2% of patients across treatment groups. Of the timing intervals explored, the highest incidence of grade 3/4 infection occurred within the first 6-month interval of study treatment initiation in both groups. Median time to the first onset of grade 3/4 infections (per Kaplan-Meier estimates) was 83.3 months and not estimable in the D-Rd/D-VMP and Rd/VMP groups, respectively. Although the rates of D-Rd/D-VMP treatment discontinuation due to infection remained low in MAIA and ALCYONE, clinicians should remain vigilant about infections throughout treatment and follow local guidelines and International Myeloma Working Group recommendations to minimize the risk of infection. These trials were registered at www.ClinicalTrials.gov as NCT02252172 (MAIA) and NCT02195479 (ALCYONE).

Objective Meaningful assessments of how large language models (LLMs) incorporate clinical guidelines require large-scale testing over many queries. Here, we evaluate the prevalence of clinical guideline omissions and hallucinations in a large sample of diagnostic LLM outputs. Methods We used simulated case vignettes and zero-shot prompting to generate diagnostic outputs and rationales from GPT-4.1 and DeepSeek-V3. English case vignettes were created for hypercholesterolaemia and type-2 diabetes mellitus. Each vignette contained identical medical information, while sociodemographic characteristics varied in terms of sex, ethnicity and location. We calculated the prevalence of existing and hallucinated clinical guidelines in LLM outputs across disease, LLM and sociodemographic characteristics. Results We analysed a total of 12 197 LLM outputs, which quantifies three hazard areas: omissions (up to 97% for DeepSeek-V3 and 46% for GPT-4.1), hallucinations (up to 9%) and inconsistencies (guideline citation rate ranging from 0% to 78.39% across sociodemographic vignettes). Omission and hallucination rates were generally similar across vignettes with different sex or ethnicity data, yet were particularly sensitive to patient location. Discussion This study highlights significant variability in clinical guideline prediction across two different diseases, three different sociodemographic variables and two LLMs, even when the LLMs were instructed by identical prompts, establishing clinical guideline prediction in LLM outputs as a stochastic event. Conclusion The stochastic nature of LLMs creates a unique challenge for evidence generation and clinical deployment. Being able to measure and capture this stochasticity within high-quality research designs will be a prerequisite to advancing the responsible deployment of LLMs in healthcare.

Importance Novel blood culture diagnostics provide rapid antimicrobial susceptibility testing (AST) results for bacteria causing bloodstream infections (BSIs) but have unclear clinical impact. Objective To evaluate clinical outcomes of blood culture testing using a rapid AST method compared with standard AST in patients with BSIs caused by gram-negative bacilli in regions with high prevalence of antimicrobial resistance. Design, Setting, and Participants Open-label randomized clinical trial that enrolled participants from December 2023 to May 2025 (final follow-up, June 18, 2025) at 7 medical centers in Greece (n = 2), India (n = 1), Israel (n = 3), and Spain (n = 1). Hospitalized patients (adults and children) with BSIs caused by gram-negative bacilli were eligible. Statistical analysis was conducted from August 2025 to January 2026. Intervention Patients were randomized to undergo blood culture evaluation using rapid, phenotypic AST directly from positive blood cultures plus standard susceptibility testing (n = 413) vs standard susceptibility testing alone (n = 437). Local antimicrobial stewardship teams reviewed all patients and provided treatment recommendations. Main Outcomes and Measures The primary outcome was a desirability of outcome ranking (DOOR) at day 30, with 3 categories (alive without deleterious events, alive with deleterious events, and death). The difference between rapid and standard testing was summarized as the probability that the DOOR outcomes were more desirable in the rapid testing group. Superiority was concluded if the lower limit of the 95% CI exceeded 50%. Secondary outcomes included 30-day mortality, length of hospitalization, intensive care unit admission, acquisition of hospital-acquired infections, time to effective antibiotic therapy within 3 days, and time to antibiotic escalation or deescalation within 3 days. Results Of the 899 patients randomized, 850 were included in the primary outcome analysis (median [IQR] age, 72 [21] years; 43% female). The probability that DOOR outcomes were more favorable in the rapid testing group was 48.8% (95% CI, 45.3%-52.4%). Median time to effective antibiotic therapy was not different between the groups in the as-randomized population. Median time to antibiotic escalation or deescalation was faster in the rapid testing group by 14 hours (95% CI, 6-22) in the as-randomized population. There were no differences between the groups in other secondary outcomes. In the prespecified subgroup with carbapenem-resistant infections, median time to effective therapy was 9.5 hours in the rapid testing group vs 28 hours in the standard testing group (difference, −18 hours [95% CI, −42 to 6]). Conclusions and Relevance Among patients with gram-negative bacilli BSIs, rapid blood culture AST was not superior to standard testing by DOOR. When considered with other efficacy and safety outcomes, these findings may help inform the use of rapid susceptibility testing in clinical practice. Trial Registration ClinicalTrials.gov Identifier: NCT06174649

PURPOSE Since 2012, several states have implemented mandatory paid sick leave (PSL) policies. PSL can provide patients time and income continuity to undergo screening and/or timely diagnostic workup for new cancer-related symptoms and complete lengthy and expensive cancer treatment courses. This study aimed to examine the association between mandatory PSL policies and cancer stage at diagnosis and overall survival (OS). METHODS Adults age 18-64 years diagnosed with cancer were identified from the Surveillance, Epidemiology, and End Results program registries between 2010 and 2019. Difference-in-differences (DID) analyses were used to compare absolute changes in stage I and stage IV diagnoses and 1-year OS before and after policy implementation in states that enacted mandatory PSL relative to states that did not enact such policies. RESULTS A total of 1,052,307 patients with cancer were included. In adjusted DID analyses, there were a 0.83 (95% CI = –1.49 to –0.16, P = .014) PP decrease in stage IV diagnoses and a 0.63 (95% CI = 0.10 to 1.17, P = .021) PP increase in 1-year OS associated with implementation of mandatory PSL policies. In exploratory analyses, males and individuals with lung cancer experienced the greatest shifts in policy-associated changes in stage at diagnosis and OS. CONCLUSION PSL policy implementation is associated with decreased late-stage diagnoses and improved OS in patients with cancer. Policies that improve opportunities to receive medical care may facilitate earlier cancer detection and ultimately contribute to better patient outcomes.

ABSTRACT Intrinsic Acinetobacter -derived cephalosporinases (ADCs) in Acinetobacter baumannii are AmpC-type β-lactamases that confer resistance to β-lactam agents, typically through insertion sequence (IS) element-driven overexpression. However, the contribution of ADCs to resistance against advanced β-lactam agents has not been systematically investigated. Given the increasing clinical use of these agents, including cefiderocol, we analyzed the diversity and function of ADC variants in a global collection of carbapenem-resistant A. baumannii (CRAb) isolates. We identified 52 distinct ADC variants in a collection of 428 CRAb clinical isolates from the United States. Among these, variants carrying both a valine substitution at position 292 in the R2 loop and an alanine duplication (ADUP) in the Ω loop consistently conferred stable resistance to cefiderocol. Biochemical and crystallographic analyses demonstrated that ADC-227, which harbors a V292W substitution with an ADUP at position 218a in the Ω loop, exhibits enhanced catalytic efficiencies for ceftazidime and cefiderocol and moderately reduced inhibition by avibactam, leading to resistance not only to cefiderocol but also to ceftazidime–avibactam. Structural studies revealed conformational flexibility of the R2 loop, allowing dynamic accommodation of substrates. Collectively, the findings identify Val292, in combination with an ADUP in the Ω loop, as a mutational “hot spot” for ADCs evolution that may undermine the efficacy of newer β-lactams, including cefiderocol. These results underscore the need for ongoing molecular surveillance of A. baumannii isolates to detect and track the emergence of such variants in clinical settings. IMPORTANCE Carbapenem-resistant Acinetobacter baumannii (CRAb) has been designated as a critical priority pathogen by the World Health Organization (WHO). Cefiderocol has been introduced as a novel therapy against CRAb; however, recent clinical data highlight concerning treatment failures and excess mortality. Understanding resistance mechanisms is therefore essential to preserve the clinical utility of this agent. This study addresses a critical knowledge gap by investigating the role of intrinsic Acinetobacter -derived cephalosporinases (ADCs), which are ubiquitous in A. baumannii and diverse in sequence. By defining specific mutational patterns that endanger cefiderocol activity, this work highlights how chromosomally encoded enzymes can evolve to erode the effectiveness of newer β-lactams such as cefiderocol. These insights underscore the importance of integrating molecular surveillance into clinical practice and antimicrobial stewardship to ensure timely detection of emerging resistance in clinical A. baumannii isolates, ultimately informing treatment strategies and guiding future drug development.

Abstract Background: Glioblastoma recurrence is inevitable despite aggressive surgical resection of contrast enhancing (CE) tumor. Unlike the deep molecular characterization of CE glioblastoma, unresected infiltrating tumor, representing minimal residual disease (MRD) has not been well profiled. Increasingly, clinical trials are being conducted in the MRD setting for glioblastoma patients, necessitating understanding of unresected infiltrating tumor for targeted therapeutic development. Methods: Visium HD spatial transcriptomics was used to profile a cohort of newly diagnosed, treatment-naïve glioblastoma patients that underwent supramaximal resection, with both core and infiltrating in situ components. Spatial profiles generated expression signatures of infiltrative and CE tumor. For in silico prediction of therapeutics targeting the MRD, expression signatures of infiltrative and CE tumor were compared with drug perturbation signatures from the NIH L1000 database using the sRGES method to predict reversal of disease expression patterns. IC50 data from human cell lines were aggregated from the Genomics of Drug Sensitivity in Cancer or individual study data while blood-brain barrier (BBB) penetrance was predicted using the CNS-MPO approach. Findings: Infiltrative tumor expression profiles were enriched for genes corresponding to neural and oligodendrocyte progenitor like cells. In contrast CE glioblastoma displayed mesenchymal and astrocytic programs, suggesting spatial concentration of glioblastoma states within MRD and CE tumor. For CE glioblastoma, proteasome inhibitors and glucocorticoid receptor agonists were predicted to have the highest antitumor activity. In contrast, histone deacetylase inhibitors (HDACi) were highly ranked for MRD while exhibiting low predicted efficacy in CE tumor. Synergy analysis of drug candidates provided multiple dual treatment options for both the CE and MRD contexts. Conclusions: Cumulatively, these data indicate that the resected tumor does not reflect the MRD state, providing clarity on why targeted therapeutics for glioblastoma have not been particularly successful. Spatial profiling of the MRD demonstrates vulnerability to unique drug targets, which if utilized in the correct setting could confer greater survival benefit. Citation Format: Harrshavasan Congivaram, Shashwat Tripathi, Mateo Gomez, Katy McCortney, Ching Man Wai, Ruochen Du, Thomas K. Sears, Jianzhong Zhang, Daniel J. Brat, Craig M. Horbinski, Mark W. Youngblood, Jared T. Ahrendsen, Adam M. Sonabend, Stephen T. Magill, Matthew C. Tate, Maciej S. Lesniak, Sean Sachdev, Timothy Sita, Priya Kumthekar, Karan Dixit, Robin Buerki, Ditte Primdahl, Mustafa Khasraw, John de Groot, David A. Reardon, Rimas V. Lukas, Roger Stupp, Amy B. Heimberger. In silico screening of therapeutics candidates targeting minimal residual disease in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2496.

Abstract Background and Aims Stroke and systemic embolism are recognized but poorly characterized complications of atrial fibrillation (AF) and left atrial flutter (AFL) catheter ablation. Their incidence, outcomes, and procedural associations remain insufficiently defined. Methods Retrospective global registry was initiated by the European Heart Rhythm Association Scientific Committee. A secure database captured data from ablation centres worldwide on general AF and left AFL ablation activity, as well as detailed information on patients with symptomatic embolic events between 2017 and 2024. Results Overall, 204 centres reported 335 743 ablation procedures and 550 embolic events (incidence 0.16%). Centre-level rate ranged from 0% to 3.1%. Most events were cerebral (94%), followed by peripheral (5%), and combined (1%). Coronary air embolism accounted for 62% of all peripheral events. Intraprocedural events occurred in 93 patients (17%), within 72 h in 357 (78%) and beyond 72 h in 100 (22%); 128 cases (23%) were diagnosed after hospital discharge. Nonparoxysmal AF (0.23% vs 0.15%; P < .001), centre experience, and ablation energy source (radiofrequency, 0.16%; cryoballoon, 0.16%; pulsed field ablation, 0.25%; laserballoon, 0.88%; P < .001) were associated with embolic risk. Median NIHSS score after stroke was 4 (interquartile range, 2–9). Three-month follow-up was available for 518 patients with embolism (95%): 181 (35%) had sequelae and 16 (3%) died. Conclusions Symptomatic embolic events are infrequent but associated with significant morbidity and mortality. Most events occur early, though a substantial proportion arise later. Higher event rates were observed with laser and possibly with pulsed field ablation. A greater centre experience was associated with a lower embolism incidence.