Daily Sepsis Research Analysis
Two multicenter prospective studies show that metagenomic sequencing—including a probe-capture assay—substantially improves pathogen detection in sepsis, drives antibiotic optimization, and is associated with improved early outcomes. A meta-analysis supports oral beta-lactam step-down therapy as an effective alternative to fluoroquinolones/TMP-SMX for uncomplicated gram-negative bacteremia, informing stewardship.
Summary
Two multicenter prospective studies show that metagenomic sequencing—including a probe-capture assay—substantially improves pathogen detection in sepsis, drives antibiotic optimization, and is associated with improved early outcomes. A meta-analysis supports oral beta-lactam step-down therapy as an effective alternative to fluoroquinolones/TMP-SMX for uncomplicated gram-negative bacteremia, informing stewardship.
Research Themes
- Precision metagenomic diagnostics for sepsis
- Antimicrobial stewardship and oral step-down therapy
- Linking diagnostic yield to patient-centered outcomes (SOFA, early mortality)
Selected Articles
1. Clinical implement of Probe-Capture Metagenomics in sepsis patients: A multicentre and prospective study.
In a multicenter prospective cohort (n=184), probe-capture metagenomics outperformed blood culture for pathogen detection (51.6% vs 17.4%, p<.001), achieved 100% sensitivity and 87.1% specificity versus a composite standard, and prompted antibiotic changes in 34.8% of patients. Notably, 22.3% had a >2-point SOFA score decrease after therapy adjustment, demonstrating clinical impact beyond diagnostic yield.
Impact: This is one of the first prospective, multicenter evaluations linking metagenomic results to antibiotic changes and objective outcome (SOFA), with trial registration. It demonstrates real-world clinical utility of probe-capture metagenomics in sepsis.
Clinical Implications: Probe-capture metagenomics can be integrated early (pre-antibiotics) to increase diagnostic yield and guide antibiotic optimization, with measurable improvements in organ dysfunction (SOFA). Implementation should pair with stewardship protocols and confirmatory testing.
Key Findings
- Detection rate was higher than blood culture (51.6% vs 17.4%, p<.001).
- Against combined blood culture + RT-PCR reference, sensitivity was 100%, specificity 87.1%, concordance 91.8%.
- Antibiotics were adjusted in 34.8% of patients, and 22.3% achieved >2-point SOFA reduction after adjustment.
Methodological Strengths
- Prospective multicenter cohort with pre-antibiotic sampling
- Registered study (NCT03760315) with objective outcome tracking (SOFA at days 0, 3, 7)
Limitations
- Nonrandomized design and modest sample size (n=184) may introduce selection bias
- Potential false positives/negatives inherent to capture panels; limited longer-term outcomes beyond 7 days
Future Directions: Cluster-randomized or stepped-wedge trials comparing probe-capture metagenomics-guided therapy versus standard care with 28-day mortality and cost-effectiveness endpoints; optimization of probe panels and contamination controls.
BACKGROUND: Accurate pathogen identification is critical for managing sepsis. However, traditional microbiological methods are time-consuming and exhibit limited sensitivity, particularly with blood samples. Metagenomic sequencing of plasma or whole blood was highly affected by the proportion of host nucleic acid. METHODS: We developed a Probe-Capture Metagenomic assay and established a multicentre prospective cohort to assess its clinical utility. In this study, 184 blood samples from patients suspected of sepsis were sent for blood culture and Probe-Capture Metagenomic sequencing before using antibiotics. The pathogen-positive rate and auxiliary abilities in diagnosis were compared among Probe-Capture Metagenomics, blood culture and real-time PCR (RT-PCR). Antibiotic therapy adjustments were based on the identification of pathogens, and changes in the Sequential Organ Failure Assessment (SOFA) score were monitored on days 0, 3 and 7 of admission. RESULTS: A total of 184 sepsis patients were enrolled, with a mean age of 66 years (range 56-74). The Probe-Capture Metagenomics method, confirmed by RT-PCR, demonstrated a significantly higher pathogen detection rate than blood culture alone (51.6% vs. 17.4%, p < .001). When combining the results of blood culture and RT-PCR, Probe-Capture Metagenomics achieved a concordance rate of 91.8% (169/184), with a sensitivity of 100% and specificity of 87.1%. In terms of clinical impact, antibiotic therapy was adjusted for 64 patients (34.8%) based on the results from Probe-Capture Metagenomics, and 41 patients (22.3%) showed a > 2-point decrease in SOFA score following antibiotic adjustments. CONCLUSION: Probe-Capture Metagenomics significantly enhances the ability of pathogen detection compared with traditional metagenomics. Compared to blood culture and RT-PCR in sepsis patients, it leads to improved antibiotic treatment and better patient outcomes. This study, for the first time, evaluates the clinical impact of metagenomic sequencing by integrating antibiotic adjustments and SOFA score changes, indicating that approximately one-fifth of sepsis patients benefit from this advanced diagnostic approach. TRIAL REGISTRATION: This study has been registered in clinical trials (clinicaltrials.gov) on 30 November 2018, and the registration number is NCT03760315. KEY POINTS: Probe-Capture Metagenome had a significantly higher positive rate than blood culture (51.6% vs. 17.4%, p < .001). Combining blood culture and RT-PCR results, Probe-Capture Metagenome achieved a consistency rate of 91.8%. Antibiotics were adjusted in 34.8% of patients based on Probe-Capture Metagenome results, and 22.3% of patients experienced a more than 2-point decrease in SOFA score.
2. Impact of metagenomics next-generation sequencing on etiological diagnosis and early outcomes in sepsis.
In a 19-site prospective cohort (n=859), mNGS on infected site samples had higher positive agreement than conventional microbiological testing (92.0% vs 51.1%) but lower negative agreement. It identified causal microbes in 74% and led to antibiotic adjustments in 29.2%. Early mortality (7-day) was reduced (HR 0.44), while 28-day mortality was unchanged.
Impact: This large prospective study connects mNGS diagnostic yield to antibiotic changes and early survival, providing pragmatic evidence for integrating mNGS into sepsis workflows.
Clinical Implications: Adjunctive mNGS of infected site samples can accelerate etiological diagnosis and guide targeted therapy, potentially reducing early mortality. Programs should address false negatives/positives, turnaround time, and stewardship oversight.
Key Findings
- Positive percent agreement of mNGS vs CMT: 92.0% vs 51.1% (p<0.001); negative agreement lower for mNGS (39.6% vs 69.2%).
- Causal microbes identified in 74.0% with mNGS; antibiotic changes in 29.2%.
- 7-day mortality reduced (HR 0.44), but no difference in 28-day mortality (HR 0.82).
Methodological Strengths
- Prospective multicenter design (19 sites) with IPTW to reduce selection bias
- Concurrent CMT and mNGS for within-patient diagnostic comparison
Limitations
- Nonrandomized, patient-choice design risks residual confounding despite IPTW
- Lower negative agreement and potential contamination limit specificity; conducted in one country
Future Directions: Randomized or pragmatic trials to test mNGS-guided care pathways on 28-day mortality, time-to-appropriate therapy, and costs; harmonization of interpretation frameworks and contamination control.
BACKGROUND: Clinical implications of metagenomics next-generation sequencing (mNGS) in sepsis have not been fully evaluated. This study aimed to determine the diagnostic, therapeutic, and prognostic impacts of mNGS in sepsis. METHODS: This multicenter prospective study was conducted at 19 sites in China from 2020 to 2021, and 859 adult patients hospitalized with sepsis were enrolled. The advantages, challenges, knowledge gaps and privacy risks of mNGS were carefully introduced to all participants, and participants chose on their own to either receive conventional microbiological test (CMT) alone (conventional-test-only group, n = 394) or receive mNGS test along with CMT (combined test group, n = 465). For prognostic analysis, the primary endpoint was 28-day mortality. Secondary endpoints included 7-day mortality and average per-day hospital cost. Inverse probability of treatment weighting was used to balance covariates between groups. Concurrent CMT and mNGS results from patients in the combined test group were used for diagnostic analyses. Therapeutic impact of mNGS was evaluated based on subsequent antibiotic adjustment. RESULTS: Compared with composite reference standard, the positive percent agreement of mNGS among infected site samples was significantly higher than that of CMT (92.0% [95% CI, 88.7 to 94.5] vs. 51.1% [95% CI, 45.9 to 56.2], p < 0.001), while the negative percent agreement of mNGS was inferior to that of CMT (39.6% [95% CI, 29.5 to 50.4] vs. 69.2% [95% CI, 58.7 to 78.5], p < 0.001). The mNGS test identified causal microbes in 344 (74.0%) patients, and concomitant antibiotic changes occurred in 136 patients (29.2%). Death by day 7 occurred in 24 of 465 (5.2%) patients in the combined test group and in 34 of 394 (8.6%) patients in the conventional-test-only group (hazard ratio, 0.44 [95% CI, 0.26 to 0.77], p = 0.004). However, no significant difference in 28-day mortality was observed between two study groups (hazard ratio, 0.82 [0.56 to 1.20], p = 0.300). CONCLUSIONS: The mNGS test of infected site samples exhibited 40% higher pathogen detection rate than CMT in patients with sepsis, which led to improved etiological diagnosis and tailored antibiotic therapy. Additional use of mNGS halved the risk of early death in 7 days, but did not improve 28-day survival in patients with sepsis. TRIAL REGISTRATION: chictr.org.cn Identifier: ChiCTR2000031113. Registered 22 March 2020.
3. Transition to oral beta-lactam therapy in uncomplicated gram-negative bacteremia: A systematic review and meta-analysis.
Across 8 retrospective cohorts (n=7500) of uncomplicated gram-negative bacteremia, step-down to oral beta-lactams had similar 30-day all-cause mortality and antibiotic failure as fluoroquinolones/TMP-SMX. Baseline characteristics were broadly comparable between groups.
Impact: Synthesizes the best available evidence supporting oral beta-lactams as a safe step-down option, potentially reducing reliance on fluoroquinolones and informing stewardship and patient-centered care.
Clinical Implications: For stable, uncomplicated GNB, clinicians can consider oral beta-lactams for step-down therapy without compromising 30-day outcomes, aligning with antimicrobial stewardship and minimizing fluoroquinolone exposure.
Key Findings
- No significant difference in 30-day all-cause mortality between oral beta-lactams and FQ/TMP-SMX (RR 1.24, 95% CI 0.86-1.77).
- No significant difference in 30-day antibiotic failure (RR 1.29, 95% CI 0.97-1.71).
- Baseline demographics and infection sources were similar across groups, supporting comparability.
Methodological Strengths
- Systematic review and meta-analysis synthesizing 8 cohorts (n=7500)
- Clinically meaningful outcomes (30-day mortality and failure) with balanced baseline characteristics
Limitations
- All included studies were retrospective cohorts; potential residual confounding and heterogeneity in dosing/regimens
- Applicability limited to uncomplicated infections; not necessarily generalizable to severe sepsis or deep foci
Future Directions: Prospective pragmatic trials comparing specific oral beta-lactam agents/doses and stewardship-guided selection; subgroup analyses by source control, MICs, and patient comorbidities.
INTRODUCTION: Gram-negative bacteremia (GNB) is associated with significant morbidity and mortality. Transition to oral therapy has traditionally utilized fluoroquinolones or trimethoprim-sulfamethoxazole rather than beta-lactams due to concerns about pharmacokinetics and bioavailability despite a dearth of clinical data. The purpose of this meta-analysis is to evaluate the clinical efficacy of transition to oral beta-lactam therapy in uncomplicated GNB. METHODS: We performed a meta-analysis of published articles in MEDLINE, Embase, and Web of Science databases from inception to September 2024. Inclusion criteria included any study with adults (age >18 years of age) with uncomplicated GNB from any source. Primary outcomes included 30-day all-cause mortality and 30-day antibiotic failure rate. RESULTS: Eight retrospective cohort studies were reviewed comprising 7500 patients. Twice as many patients were in the fluoroquinolones/trimethoprim-sulfamethoxazole group compared with the beta-lactams group (4998 vs. 2482). Patients in each group had similar average age (70 vs. 71), percent male (54% vs. 56%), percent urinary source (78% vs. 80%), duration of IV antibiotics (4.2 vs. 4.5), Pitt bacteremia score (1.1 vs. 1.4) and Charleston comorbid index (2 vs. 2). There was no statistically significant difference in the 30-day all-cause mortality rate between the fluoroquinolones/trimethoprim-sulfamethoxazole and the beta-lactams group: 2.06% versus 1.89% with a weighted relative risk ratio of 1.24 (95% confidence interval [CI]: 0.86-1.77) or the 30-day antibiotic failure rate: 2.08% vs. 3.42%, weighted relative risk ratio of 1.29 (95% CI: 0.97-1.71). CONCLUSIONS: There is no statistically significant difference in 30-day mortality or antibiotic failure rates between BL and FQ/TMP-SMX as transition to oral therapy in treating uncomplicated GNB.