Daily Sepsis Research Analysis
Analyzed 20 papers and selected 3 impactful papers.
Summary
Three clinically oriented studies advanced sepsis care today: a prospective cohort showed that dynamic preoperative urinalysis (uWBC and nitrite) stratifies risk of postoperative fever and urosepsis after PCNL; an observational study in febrile neutropenia integrated host-response transcriptomics (SeptiCyte RAPID) and culture-independent T2MR, improving early diagnostic discrimination; and a large ICU cohort linked initial serum bicarbonate to septic shock mortality in a U-shaped fashion, informing acid-base management.
Research Themes
- Perioperative infection risk stratification using dynamic urinalysis
- Host-response and culture-independent diagnostics for febrile neutropenia
- Acid-base biomarkers and mortality in septic shock
Selected Articles
1. Can dynamic changes in preoperative urinary white blood cells and nitrite predict infectious complications after percutaneous nephrolithotomy in culture-positive patients?
In a prospective cohort of 346 culture-positive PCNL candidates, lack of improvement or persistent positivity in preoperative urinary WBC and nitrite strongly predicted postoperative infectious complications. Persistently positive nitrite conferred the highest risk for urosepsis (adjusted OR 7.32), supporting dynamic urinalysis as a low-cost risk stratification tool when culture turnaround is delayed.
Impact: This study operationalizes a simple, repeatable preoperative biomarker trend to anticipate urosepsis, enabling targeted perioperative management without additional infrastructure.
Clinical Implications: Patients with persistently positive/increasing uWBC or nitrite may warrant intensified antibiotics, optimization of surgical timing, and enhanced postoperative monitoring to mitigate urosepsis risk.
Key Findings
- Postoperative fever and urosepsis incidences were 20.8% and 3.2%, respectively.
- Persistently positive or increased uWBC independently predicted postoperative fever (adjusted OR 1.95–2.62; P<0.05), with a significant dose-response (P for trend=0.011).
- Persistently positive nitrite independently predicted urosepsis (adjusted OR 7.32; P=0.012) and postoperative fever (adjusted OR 2.41; P=0.024).
- Associations were consistent across clinical subgroups; conversion from nitrite-negative to -positive was not independently predictive.
Methodological Strengths
- Prospective observational design with two preoperative urinalysis timepoints capturing temporal trends
- Multivariable logistic regression and pre-specified subgroup analyses supporting robustness
Limitations
- Non-randomized observational design limits causal inference
- Restriction to culture-positive patients may limit generalizability; temporal window limited to admission-to-surgery interval
Future Directions: Validate dynamic urinalysis-based risk models in multicenter cohorts, integrate with stone burden and comorbidity data, and assess whether management changes reduce urosepsis.
BACKGROUND: Percutaneous nephrolithotomy (PCNL) frequently encounters postoperative infectious complications, notably fever and urosepsis. Although preoperative urine culture guides antibiotics, delayed reporting hampers timely risk stratification. Urinalysis is simple, cost-effective, and repeatable; however, most existing studies focus on single static measurements and lack systematic evaluation of temporal trends. OBJECTIVE: To evaluate the association between temporal changes in preoperative urinary white blood cells (uWBC) and nitrite (NIT) and the risk of postoperative fever and urosepsis in patients undergoing PCNL. METHODS: We conducted a prospective observational study of 346 culture-positive patients undergoing PCNL (March 2021-July 2025). Urinalysis was performed at admission and on the morning of surgery. All patients received 5-7 days of pathogen-directed intravenous antibiotics before surgery. Patients were classified according to the trend of uWBC and NIT changes between the two tests. Both univariate and multivariate logistic regression models were applied to assess the relationships with postoperative fever and urosepsis, and pre-specified clinical subgroup analyses were conducted. RESULTS: Postoperative fever and urosepsis occurred in 20.8% (72/346) and 3.2% (11/346) of patients, respectively. Compared with patients whose uWBC decreased or remained negative, those with persistently positive or increased uWBC independently predicted postoperative fever (adjusted OR 1.95-2.62, P < 0.05), with a significant dose-response relationship (P for trend = 0.011). Using persistently negative NIT as the reference, persistently positive NIT independently predicted urosepsis (adjusted OR 7.32, P = 0.012) and postoperative fever (adjusted OR 2.41, P = 0.024). Associations were consistent across clinical subgroups. CONCLUSIONS: Dynamic preoperative urinalysis offers a simple, inexpensive, and reproducible approach to stratify infection risk in culture-positive PCNL candidates; lack of improvement or persistent positivity in uWBC, as well as persistently positive NIT, identifies high-risk patients and supports individualized perioperative management, whereas conversion from NIT-negative to NIT-positive status-an infrequent pattern in our cohort-was not independently predictive of postoperative infectious complications. Incorporating dynamic urinalysis changes with stone burden, diabetes, and other clinical characteristics may facilitate preoperative risk stratification and individualized infection-prevention strategies.
2. Host Transcriptomics and Culture-Independent Testing for the Management of Febrile Neutropenia: Data From an Observational Study Conducted in a Bone Marrow Transplant Unit.
In 90 febrile neutropenia episodes post–bone marrow transplant, T2Candida detected candidemia in 3 hours (vs ~42 hours for blood culture), while SeptiCyte RAPID achieved an AUC of 0.84 for identifying infectious fever. Limited bacterial panel coverage constrains T2Bacteria utility, but host-response testing appears promising for triage.
Impact: This study integrates host transcriptomics with rapid, culture-independent detection, offering a practical path to earlier, more accurate decisions in a population at extreme risk of sepsis.
Clinical Implications: Use SeptiScore to prioritize infectious etiologies in febrile neutropenia and consider T2Candida to expedite antifungal therapy, while recognizing limited bacterial coverage of T2MR when selecting diagnostics.
Key Findings
- Among 90 febrile episodes, 11 had positive blood cultures for bacteria; only 3/11 matched T2Bacteria on-panel organisms.
- T2Candida identified four candidemia cases with a 3.0-hour turnaround versus 42.4 hours for blood culture (p=0.014).
- SeptiCyte RAPID yielded valid SeptiScores in 86/90 episodes; AUC for infectious fever discrimination was 0.84 (95% CI 0.71–0.97).
Methodological Strengths
- Real-world head-to-head comparison of T2MR vs. blood culture with measured turnaround times
- Integration of host-response transcriptomic assay (SeptiCyte RAPID) with clinician-adjudicated infection status
Limitations
- Small, single-unit observational study with many indeterminate episodes excluded from accuracy analysis
- Limited pathogen coverage of T2Bacteria reduces general applicability; infection classification was retrospective
Future Directions: Conduct larger, prospective, multicenter diagnostic accuracy and impact studies, including cost-effectiveness and antimicrobial stewardship outcomes, and evaluate expanded panels.
BACKGROUND: Managing febrile neutropenia is challenging due to the limited sensitivity of blood culture (BC) and the lack of tools differentiating infectious from non-infectious fever. T2 magnetic resonance (T2MR) is a culture-independent system detecting bacteria (T2Bacteria) and yeasts (T2Candida); SeptiCyte RAPID is a host response assay providing a likelihood of sepsis (SeptiScore). METHODS: We conducted an observational study including bone marrow transplant patients with febrile neutropenia to assess (1) the performance of T2MR versus BC (2) the performance of SeptiScore in providing valid results and diagnosing infection compared to a retrospective clinician diagnosis. RESULTS: We included 90 febrile episodes. Eleven episodes had BC growing bacteria, of which 3/11 were T2Bacteria on-panel pathogens. T2Candida identified four Candida with a turnaround time of 3.0 h (IQR 3.0-3.0), significantly shorter than BC (42.4 h, IQR 39.8-50.9, p = 0.014). A SeptiScore was obtained in 86/90 cases. Febrile episodes were classified as: infectious (21/86, 24%), probably infectious (13/86, 15%), indeterminate (excluded from analysis; 40/86, 46%), non-infectious (12/86, 14%). The AUC of SeptiScore for infectious fever was 0.84 (95% CI 0.71-0.97). CONCLUSION: Despite the short turnaround time, T2MR showed limited coverage of bloodstream pathogens. SeptiScore may help in diagnosing infectious neutropenic fever, but larger studies should clarify its clinical utility.
3. Association between serum bicarbonate and 28-day mortality in septic shock patients: A cohort study.
Using MIMIC-IV, initial serum bicarbonate in 5,287 septic shock patients showed a U-shaped association with 28-day mortality: risk decreased below 20 mEq/L with higher bicarbonate and increased above 27 mEq/L. The findings support personalized acid-base targets rather than uniform correction strategies.
Impact: This large-scale analysis quantifies nonlinearity in a ubiquitous biomarker, offering actionable thresholds to refine resuscitation and buffering strategies in septic shock.
Clinical Implications: Avoid overcorrection of bicarbonate; monitor and manage both low and high extremes, and design trials to test target ranges for acid-base therapy in septic shock.
Key Findings
- Among 5,287 septic shock ICU patients, 28-day mortality was 31.4%.
- Generalized additive modeling showed a significant U-shaped association between initial bicarbonate and mortality (edf=2.96, χ²=62.33, P<.001).
- Below 20 mEq/L, each 1 mEq/L increase in bicarbonate reduced mortality risk (OR=0.91; 95% CI 0.88–0.93; P<.0001); above 27 mEq/L, each 1 mEq/L increase raised risk (OR=1.11; 95% CI 1.02–1.20; P=.0185).
Methodological Strengths
- Large ICU cohort with multivariable logistic modeling
- Use of generalized additive models to capture nonlinear associations
Limitations
- Retrospective design with ICD-coded septic shock identification may introduce misclassification
- Residual confounding and lack of granular intervention data (e.g., bicarbonate administration) limit causal interpretation
Future Directions: Prospective validation and randomized trials to test bicarbonate target ranges; explore mechanistic links between extreme bicarbonate levels and outcomes.
Septic shock, a high-mortality subtype of sepsis, is associated with significantly elevated mortality rates compared to sepsis without shock. Although metabolic acidosis (reflected by serum bicarbonate levels) is a common complication in septic shock, robust evidence regarding the prognostic value of initial serum bicarbonate specifically in intensive care unit (ICU)-admitted septic shock patients remains limited. This study therefore aimed to evaluate the association between initial serum bicarbonate and 28-day mortality in a large cohort of septic shock patients. This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care IV (v2.2) database, which contains de-identified records of 73,181 adult ICU admissions (2008-2019). Adult patients with septic shock were identified using international classification of diseases -9 (785.52) and international classification of diseases-10 (R6521, T8112XA) codes (n = 7216). Inclusion required an available first recorded serum bicarbonate level during the index ICU admission; patients with missing bicarbonate or mortality data were excluded. The primary exposure was serum bicarbonate, and the primary outcome was 28-day all-cause mortality. Multivariable logistic regression was used to assess the association, expressed as odds ratios (ORs) with 95% confidence intervals (CIs). Nonlinearity was explored using generalized additive models. Among 5287 ICU patients (median age 67.7 years), 1662 (31.4%) died within 28 days. Generalized additive modeling revealed a significant U-shaped association between serum bicarbonate and 28-day mortality (edf = 2.96, χ² = 62.33, P < .001). Below 20 mEq/L, each 1 mEq/L increase was associated with a significantly reduced 28-day mortality risk (OR = 0.91, 95% CI 0.88-0.93, P < .0001). Above 27 mEq/L, each 1 mEq/L increase was associated with a significantly increased mortality risk (OR = 1.11, 95% CI 1.02-1.20, P = .0185). In patients with septic shock, the association between serum bicarbonate and 28-day mortality risk followed a U-shaped curve. Both lower and higher serum bicarbonate levels were associated with an increased risk of 28-day mortality. These findings highlight the need for personalized acid-base management strategies.