Daily Sepsis Research Analysis
Analyzed 28 papers and selected 3 impactful papers.
Summary
Single-cell profiling delineated distinct T-cell exhaustion in sepsis versus enhanced adaptive signatures in pre-septic high-risk states, refining our mechanistic understanding of immune trajectories. A large multicenter pediatric ICU study modified the Phoenix Sepsis Score and improved mortality prediction performance. An international target trial emulation found no advantage of combination over monotherapy for Enterococcus faecalis bacteremia without endocarditis, supporting antimicrobial stewardship.
Research Themes
- Immune phenotyping and TCR repertoire dynamics in sepsis
- Risk stratification and prognostic modeling in pediatric sepsis
- Antimicrobial stewardship in gram-positive bacteremia management
Selected Articles
1. Distinct landscapes of T-cell immunity and TCR repertoire between sepsis and pre-septic high-risk states.
Using scRNA-seq and scTCR-seq, the study shows broad T-cell exhaustion across subsets in sepsis, contrasted with enhanced adaptive T-cell signatures in pre-septic high-risk individuals. Peripheral TCR repertoire profiling supports distinct clonal dynamics between states and highlights a potentially distinct CD4 subset.
Impact: Provides mechanistic, single-cell resolution mapping of adaptive immunity across disease stages, informing biomarker development and timing of immunomodulation.
Clinical Implications: Supports immune monitoring strategies (e.g., exhaustion markers and TCR clonality) to stratify patients and potentially guide therapies aimed at reversing T-cell exhaustion in sepsis.
Key Findings
- Sepsis patients exhibited multi-subset T-cell exhaustion compared with non-high-risk controls.
- High-risk pre-septic individuals showed enhanced adaptive T-cell signatures rather than exhaustion.
- Peripheral TCR repertoire profiling revealed distinct clonal patterns between high-risk and septic states and suggested a distinct CD4 subset.
Methodological Strengths
- Combined scRNA-seq with scTCR-seq to link phenotype with clonal dynamics.
- Comparative design across non-high-risk, high-risk, and septic states enhances interpretability of immune trajectories.
Limitations
- Likely single-center and cross-sectional sampling limit causal inference and generalizability.
- Functional validation of identified T-cell subsets and exhaustion pathways was not detailed.
Future Directions: Prospective, multi-center validation with longitudinal sampling and interventional studies targeting exhaustion pathways to assess clinical benefit.
Sepsis remains a leading cause of in-hospital mortality worldwide. In recognition of its substantial morbidity and mortality even with optimal treatment, the World Health Organization has declared sepsis a global health priority. The immunoregulatory mechanisms in sepsis are highly complex, and the immune status during the disease course is closely associated with both short- and long-term patient outcomes, making early recognition and intervention critical for survival. While single-cell RNA sequencing (scRNA-seq) has been widely applied to decipher innate immune responses in sepsis patients, in-depth characterization of T lymphocyte subsets remains relatively limited. Urosepsis is a common complication of urinary tract stones. Although clinical studies have identified several risk factors for urosepsis, the immunological alterations in high-risk individuals are poorly understood. Here, we employed single-cell transcriptomics to investigate T-cell immunological changes in high-risk urosepsis patients and septic patients, complemented by single-cell T cell receptor (TCR) sequencing (scTCR-seq) to profile the peripheral TCR repertoire in these two pathological states. Our analysis revealed that, compared to non-high-risk controls, septic patients exhibited features of T cell exhaustion across multiple subsets, whereas high-risk individuals showed signs of enhanced T cell-mediated adaptive immunity. Notably, we identified a distinct CD4
2. Validation and modification of the phoenix sepsis score for predicting in-hospital mortality in children with suspected infection admitted to the intensive care unit.
In a 9,221-patient multicenter pediatric ICU cohort, the Phoenix Sepsis Score had only moderate discrimination for in-hospital mortality (AUROC 0.60). A modified, clinically feasible PSS+ incorporating key comorbidities and vital signs improved performance (AUROC 0.75 internal; 0.71 external), outperforming PSS variants and pSOFA.
Impact: Delivers a validated, improved mortality risk score tailored for pediatric ICU patients, enabling better triage and resource allocation.
Clinical Implications: Adopting PSS+ may enhance early risk stratification, guide escalation decisions, and prioritize monitoring in pediatric ICU patients with suspected infection.
Key Findings
- Original Phoenix Sepsis Score had moderate discrimination for in-hospital mortality (AUROC 0.60).
- Modified PSS+ incorporating comorbidities, vital signs, and demographics improved AUROC to 0.75 (internal) and 0.71 (external).
- PSS+ outperformed PSS variants (PSS-4, PSS-8) and pSOFA in both validation settings.
Methodological Strengths
- Large, multicenter cohort with both internal and external validation.
- Transparent feature selection using XGBoost with SHAP for interpretability and clinical feasibility.
Limitations
- Retrospective design may introduce residual confounding and selection bias.
- Model performance may vary in different healthcare systems; prospective validation is needed.
Future Directions: Prospective implementation studies to assess clinical impact, calibration drift monitoring, and integration into clinical workflows with decision support.
BACKGROUND: The Society of Critical Care Medicine Pediatric Sepsis Definition Task Force recommends the use of the Phoenix Sepsis Score (PSS) to diagnose pediatric sepsis among children with suspected infection. However, the performance of the PSS in different healthcare settings remains unclear. The present study aimed to validate and modify the ability of the PSS to predict in-hospital death in children with suspected infection admitted to the intensive care unit (ICU) in China. METHODS: This multicenter retrospective cohort study included children aged ≤18 years with suspected infection admitted to the ICU from five hospitals in China between January 2012 and December 2023. Two children's specialized hospitals and three tertiary general hospitals participated. The primary evaluation of PSS prediction performance was based on in-hospital mortality discrimination through the area under the receiver operating characteristic curve (AUROC). The secondary evaluation was conducted using the area under the precision-recall curve (AUPRC). Given the moderate discriminative performance of the PSS in this cohort, we employed extreme gradient boosting (XGBoost) with SHapley Additive exPlanations (SHAP) to identify key predictors of in-hospital mortality. Predictors selected through this process were incorporated into the original PSS framework while prioritizing clinical feasibility, resulting in a modified score, PSS+, for mortality prediction. RESULTS: Among 9221 ICU admissions for children with suspected infections (13.4% mortality), the PSS showed moderate discrimination, with an AUROC of 0.60 (95% CI: 0.59-0.62). The modified PSS (PSS+), which selectively incorporated comorbidities, vital signs, and demographic variables identified through model development, outperformed the original PSS-4, PSS-8, and pediatric sequential organ failure assessment (pSOFA) in terms of both internal validation (AUROC of 0.75, 95% confidence interval [CI]: 0.70-0.78) and external validation (AUROC of 0.71, 95% CI: 0.69-0.73). CONCLUSIONS: The PSS demonstrated only moderate ability to predict in-hospital mortality among pediatric ICU patients in the present cohort, indicating that its application in other healthcare settings should be approached with caution. The modified PSS+ scoring system significantly improved mortality prediction performance and may serve as a more reliable and clinically applicable tool for risk assessment in critically ill children.
3. Monotherapy vs combination therapy for Enterococcus faecalis bacteremia: a target trial emulation.
In 373 adults with monomicrobial E. faecalis bacteremia and negative echocardiography, combination therapy (mostly ampicillin plus ceftriaxone or gentamicin) did not improve 90-day composite outcomes versus monotherapy (mostly ampicillin). Sepsis or septic shock at presentation was the only independent factor associated with clinical failure.
Impact: Challenges the assumed benefit of combination therapy in EF-BSI without endocarditis using a robust target trial emulation, informing stewardship and simplifying regimens.
Clinical Implications: Monotherapy (e.g., ampicillin) may suffice for EF-BSI without endocarditis, reducing toxicity and resource use; combination therapy can be reserved for specific indications.
Key Findings
- No significant difference in 90-day composite clinical failure between monotherapy (28%) and combination therapy (36%; p=0.185).
- Ampicillin was the predominant monotherapy; combinations were mainly ampicillin plus ceftriaxone or gentamicin.
- Sepsis or septic shock at presentation was the only independent variable associated with clinical failure in weighted Cox models.
Methodological Strengths
- Prospective multicenter international dataset analyzed via target trial emulation.
- Use of weighted uni- and multivariable Cox regression to address confounding.
Limitations
- Observational design cannot exclude residual confounding despite emulation.
- Sample size may be underpowered to detect modest differences between regimens.
Future Directions: Randomized trials to confirm non-inferiority of monotherapy and subgroup analyses (e.g., high inoculum, deep-seated foci) to refine indications for combination therapy.
OBJECTIVES: Optimal treatment for E. faecalis bloodstream infection (EF-BSI) remains a topic of debate. We aim to evaluate the effectiveness of combination therapy compared to monotherapy in patients with EF-BSI and no endocarditis. METHODS: This was a target trial emulation based on a prospective, multicenter, international dataset collected in 24 international centers from January 2019 to December 2024. We included all adult patients with monomicrobial EF-BSI with negative echocardiography within 7 days from BSI onset. Exclusion criteria were diagnosis of endocarditis, not receiving or completed the therapy at randomization. Primary endpoint was clinical failure defined as a composite of death, relapse of EF-BSI, and diagnosis of endocarditis, at 90 days. RESULTS: Overall, 373 patients were eligible for inclusion, of whom 267/373 (71%) received monotherapy, mainly ampicillin (174/267, 65%); most prescribed combination regimens were ampicillin with either ceftriaxone or gentamicin (80/106, 75%). The composite clinical failure was met by 114/373 (31%) patients. The outcomes among patients that received monotherapy or combination treatment were [75/267 (28%) versus 39/106 (36%); p=0.185] leading to an overall risk difference in favor of monotherapy of 2% (95%CI -10% to 15%). Sepsis or septic shock at the time of presentation was the only independent variables associated to clinical failure, after performing a weighted uni and multi-variable Cox regression model [aHR=0.85, 95%CI=0.52-1.39]. CONCLUSION: With the limitation of our sample size and observational design we were not able to observe a better outcome associated with combination treatment for EF-BSI. If confirmed, these results would promote therapeutic simplification according to antimicrobial stewardship principles.