Daily ReportOct 26, 2026
Sepsis, October 26 edition
We read 43 papers and selected 3.
Summary
Today’s most impactful sepsis research spans a novel metabolic adjunct that resensitizes multidrug-resistant bacteria to carbapenems, a population-wide surveillance framework for septic shock, and a systematic review showing that artificial-intelligence prediction models for postoperative sepsis are not yet ready for routine clinical use. Together, these studies illustrate advances in mechanism-based therapy, health-system benchmarking, and evidence-based restraint in clinical implementation.
Research Themes
- Mechanism-based adjunctive therapy for antimicrobial resistance
- Population-level surveillance and risk-adjusted benchmarking
- Clinical readiness and limitations of artificial intelligence prediction
Selected Articles
1. L-Histidine resensitizes multidrug-resistant bacteria to carbapenems by inhibiting New Delhi metallo-β-lactamase activity.
Using untargeted metabolomics, genetic manipulation, biochemical analysis, and a murine peritonitis-sepsis model, this study identified L-histidine as a metabolic adjuvant that restores carbapenem activity against NDM-producing bacteria. L-histidine inhibited NDM directly through zinc chelation and indirectly by increasing nickel accumulation through nikABCDE, and its combination with meropenem improved survival and reduced bacterial burden in mice.
Impact: The study proposes a readily translatable, dual-mechanism strategy to extend the usefulness of an existing last-resort antibiotic against NDM-mediated carbapenem resistance. It advances the field beyond conventional enzyme inhibition by linking antibiotic resensitization to bacterial metal homeostasis.
Clinical Implications: L-histidine could become a candidate adjunct to meropenem or related carbapenems for NDM-producing infections, potentially enabling reuse of existing antibiotics. Clinical translation requires pharmacokinetic and pharmacodynamic studies, confirmation of activity across diverse NDM variants and bacterial species, and controlled human trials.
Key Findings
- L-histidine restored carbapenem susceptibility in NDM-producing Gram-negative bacteria.
- L-histidine directly inhibited NDM through zinc chelation and indirectly suppressed NDM through nikABCDE-mediated nickel accumulation.
- L-histidine plus meropenem improved survival and reduced bacterial burden in a murine peritonitis-sepsis model with a favorable safety profile.
Methodological Strengths
- Integrated untargeted metabolomics, functional screening, biochemical inhibition, and targeted gene overexpression/deletion experiments.
- Mechanistic findings were tested in vivo using a clinically relevant murine peritonitis-sepsis model.
Limitations
- The therapeutic effect was demonstrated in mice and has not been established in human patients.
- The spectrum of activity across NDM variants, bacterial lineages, infection sites, and clinically achievable L-histidine exposures remains uncertain.
Future Directions: Future work should define pharmacokinetics, optimal dosing, resistance emergence, activity against diverse NDM variants, and interactions with the human microbiome. Multicenter clinical studies should evaluate safety and efficacy of L-histidine–carbapenem combinations in patients with confirmed NDM-producing infections.
Plasmid-mediated New Delhi metallo-β-lactamase (NDM)-producing Gram-negative pathogens have severely undermined the clinical utility of carbapenems, the last-resort antibiotics for multidrug-resistant infections. Given the limited pipeline of novel antibiotics, there is an urgent need for more effective anti-infective strategies. Through untargeted metabolomics and function screening, we find that L-histidine (L-His), a key downregulated metabolite in NDM-positive bacteria, remarkably restores carbapenem susceptibility. Mechanistically, L‑His acts through two complementary pathways: (i) direct competitive inhibition of NDM enzymatic activity via zinc chelation at the active site, and (ii) upregulation of the nickel ion transport gene cluster nikABCDE, which increases intracellular Ni2+ accumulation and further suppresses NDM function through non‑competitive inhibition.
2. RADAR-Septic Shock: A Population-Based Surveillance and Risk-Adjusted Benchmarking System for Septic Shock in Catalonia.
This retrospective population-based study created RADAR-Septic Shock from Catalonia’s administrative hospital database and captured 37,855 septic shock episodes from 2018 to 2024. The system estimated an incidence of 80.28 cases per 100,000 population in 2024, found 36.7% overall in-hospital mortality and 49.5% mortality for hospital-acquired disease, and identified substantial risk-adjusted variation among hospitals and territorial clusters.
Impact: This study demonstrates a scalable infrastructure for population-level sepsis surveillance and outcome benchmarking rather than relying on isolated hospital reports. Its ability to identify temporal trends and interhospital variation can directly support quality improvement, resource planning, and sepsis policy.
Clinical Implications: Health systems can use standardized administrative surveillance and risk-adjusted observed-to-expected mortality ratios to identify hospitals or regions requiring targeted sepsis quality-improvement interventions. The framework may also inform staffing, critical-care capacity, antimicrobial stewardship, and public-health planning, although coding validity and local calibration must be confirmed.
Key Findings
- RADAR-Septic Shock captured 37,855 septic shock episodes in Catalonia between 2018 and 2024.
- The 2024 incidence was 80.28 per 100,000 population, with 36.7% overall in-hospital mortality and 49.5% mortality for hospital-acquired septic shock.
- Risk-adjusted benchmarking identified substantial variation in outcomes across hospitals and territorial clusters, while mortality declined over time except during the COVID-19 pandemic.
Methodological Strengths
- Population-wide coverage of publicly funded hospitals over seven years with a large sample of 37,855 episodes.
- Risk-adjusted mortality modeling and observed-to-expected benchmarking enabled comparisons beyond crude mortality rates.
Limitations
- The retrospective administrative design is vulnerable to coding errors, incomplete clinical granularity, and residual confounding.
- Findings from Catalonia’s publicly funded healthcare system may not generalize directly to other countries or healthcare systems.
Future Directions: Future studies should validate septic shock coding against clinical records, incorporate physiologic and treatment-timing data, and assess whether benchmarking leads to measurable improvements in mortality and process-of-care indicators. International harmonization could enable cross-system comparisons using common definitions and calibration methods.
Background: We established RADAR-Septic Shock (Registry of Administrative Data Automatically Recorded for Septic Shock) as a population-based surveillance system to monitor the epidemiology, healthcare utilization, clinical outcomes, and risk-adjusted performance of septic shock across the Catalan publicly funded healthcare system. Methods: A retrospective population-based study was conducted using the CMBD-HA administrative database, including all public hospital discharges coded for septic shock (ICD-10-CM codes R65.21 and T81.12XA) in Catalonia between 2018 and 2024. Variables included demographic characteristics, comorbidities, source of infection, setting of acquisition, organ dysfunctions, and advanced organ support. Mortality risk was assessed using multivariable logistic regression, and model performance was evaluated using the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). Hospital benchmarking was based on observed-to-expected (O/E) mortality ratios.
3. Before Sepsis Strikes: Artificial Intelligence for Early Prediction of Postoperative Sepsis and Sepsis-Related Complications After Major Abdominal Surgery-A Systematic Review.
This systematic review evaluated 45 studies of AI and machine-learning models for postoperative sepsis and related complications after major abdominal surgery. Although some models showed promising performance, only 15 studies performed strict temporal, geographic, external-center, or independent-investigator validation; calibration and decision-curve analyses were uncommon, and no study prospectively demonstrated that model-guided care improves clinical outcomes.
Impact: The review provides an important negative conclusion: predictive discrimination alone is insufficient to justify clinical deployment of AI for postoperative sepsis. By separating clinical sepsis from related endpoints and emphasizing external validation, calibration, workflow integration, and clinical benefit, it establishes a more rigorous implementation standard.
Clinical Implications: Hospitals should not adopt postoperative sepsis AI prediction tools solely on the basis of development-set AUC or complex algorithms. Before implementation, models should undergo multicenter external validation, calibration assessment, decision-curve analysis, prospective workflow testing, evaluation of alert burden, and demonstration that their use improves patient-centered outcomes.
Key Findings
- The review included 45 studies: 11 on sepsis-related outcomes, 19 on postoperative infection or surgical-site infection, 8 on anastomotic leakage, and 5 on postoperative pancreatic fistula.
- Only 15 of 45 studies provided strict temporal, geographic, external-center, or independent-investigator validation of the principal model.
- Calibration was explicitly reported in 9 studies, decision-curve or net-benefit analysis in 7 studies, and no study prospectively evaluated whether model-guided care improved clinical outcomes.
Methodological Strengths
- Registered systematic review with independent study selection and data extraction and risk-of-bias assessment using PROBAST + AI.
- Clinically important endpoints were separated rather than treating surgical-site infection, anastomotic leakage, or pancreatic fistula as interchangeable proxies for sepsis.
Limitations
- Substantial heterogeneity in outcome definitions, surgical populations, prediction timing, predictors, and validation strategies prevented quantitative meta-analysis.
- The evidence base was observational and heterogeneous, with very low certainty for primary postoperative sepsis or septic-shock prediction.
Future Directions: Future studies should use standardized Sepsis-3 or otherwise clinically justified outcome definitions, preregister model-development and validation protocols, perform multicenter temporal and geographic external validation, report calibration and net benefit, and conduct prospective impact studies. Implementation research should evaluate whether predictions trigger effective interventions without causing alert fatigue or inequitable care.
BACKGROUND: Postoperative sepsis and related infectious complications remain major causes of morbidity after abdominal surgery. Artificial intelligence (AI) and machine learning (ML) models may support earlier risk stratification, but their generalizability and clinical readiness remain uncertain. METHODS: We systematically searched PubMed, Scopus, and CENTRAL from inception to 10 August 2026 for studies developing, validating, or evaluating AI/ML models for postoperative sepsis, postoperative infection/surgical-site infection (SSI), anastomotic leakage, or postoperative pancreatic fistula (POPF) after major abdominal or general surgery. SSI, anastomotic leakage, and POPF were analyzed as distinct postoperative endpoints and were not treated as proxy definitions of clinical sepsis. Study selection and data extraction were performed independently by two reviewers, and risk of bias and applicability were assessed using PROBAST + AI. Owing to substantial clinical and methodological heterogeneity, results were synthesized narratively.