The impact of an oral purified microbiome therapeutic on the gastrointestinal microbiome.
Bryant JA, Vulić M, Walsh EA, Allen EG Jr, Beauchemin NJ, Chafee ME, Diao L, Fenn K, Ford KA, Hasson BR, Litcofsky KD, Lombardo MJ, Martinez A, O'Brien EJ, Straub TJ, Sykes SM, Marshall LF, Winkler JA, McGovern BH, Ford CB, Wortman JR, Henn MR
- DOI
- 10.1038/s41591-025-04076-w
- Record issued
- 2026-08-10
- Engine
- 7.29.0
- Exported
- 2026-09-22
Prepared by Alpha1. This document is confidential: it is intended for the recipient it was shared with and must not be redistributed. The live record at alpha1science.com/verify/fb0ef6c6-ad4c-4f1c-bcc8-469b39e80999 is authoritative.
How this rating was calculated
- IntegrityIntegrity concern−0.5★
- ReportingEthical approvals partially met−0.25★
- ReportingStatistical analysis partially met−0.25★
- ReportingData & code availability partially met−0.25★
- Statistics were not checked: no recomputable values were found in this text — no test statistic reported with its degrees of freedom, no effect estimate printed with both a 95% CI and a p-value, and no percentage printed with both its count and its denominator.
- The numeric-impossibility checks (GRIM/GRIMMER/DEBIT/SPRITE) did not run on this paper: the pass that reads its reported means did not complete. No reported mean was checked for arithmetic impossibility.
- 01Other integrity concern
Trial NCT02437487 was first submitted to ClinicalTrials.gov on 2015-05-05, after the registered study start date of 2015-05. Retrospective registration means the protocol and outcomes were not on the public record before the study ran, which is what prospective registration exists to establish.
NCT02437487
reviewer’s wording
This Kaimen Rigor review uses Kaimen Rigor reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.
The paper is a well-conducted post hoc analysis of a randomized trial with strong reporting transparency, ethical approvals, and scientific premise. Its main methodological weaknesses are in statistical reporting (p-value thresholds instead of exact values, missing effect sizes with CIs) and data/code sharing (no public repository deposit or code). A minor ethics reporting gap (no explicit regulatory framework) and a few copyedit issues also reduce the overall robustness.
Evaluated based on the full published paper. The two independent reviewer runs largely agreed, with minor divergences on checklist-level ratings (e.g., randomization method, demographics, regulatory compliance, reagents catalog numbers, and accession numbers) that were resolved by weighing the evidence. The statistics component could not verify any recomputations due to threshold-only p-values; no errors were found but no tests were confirmed correct. The citation check found no retracted or unresolved references. The integrity check flagged a concern about retrospective registration of one trial (NCT02437487).
Numerical inconsistencies
None foundValues that contradict each other or are impossible for the stated sample: recomputed p-values and test statistics, GRIM/GRIMMER checks on summary numbers, percentages against their own counts, totals against their parts, and estimates against their own confidence intervals.
Checked — nothing surfaced.
Overstated conclusions
1 finding · worst lowConclusions that reach past what the paper's own results support — including a significance claim that no longer holds when the statistic is recomputed, and efficacy resting on an unvalidated surrogate endpoint.
- Conclusions only partially backed by the presented evidenceAssessed
8 major claims checked against the paper's own evidence: all adequately supported.
- partialReviewer 2Dosing optimization led to increased engrafting species, which in turn led to a significant reduction in risk of CDI recurrence.The dose-engraftment link and the dose-efficacy link are each supported, but the direct engraftment-to-recurrence causal chain is not tested — the paper itself notes it could not examine associations between engraftment and clinical outcome.Evidence: Phase 3 showed higher engraftment and superior efficacy to placebo, but no within-study association between engraftment and recurrence is reported.
“Optimization of dosing in the phase 3 trial led to a significant increase in engrafting species, leading to a significant reduction in risk of CDI recurrence”
LimitationsFind in source - supportedReviewers 1, 2The higher, efficacious phase 3 dose is associated with improved pharmacokinetics (VOS engraftment) compared to the phase 2 low-dose regimen.The paper shows phase 3 engraftment was similar to the phase 1 high-dose group and higher than phase 2 at all shared timepoints (MWU, P < 0.01), backing the claim.Evidence: Engraftment comparisons across trials (Fig. 1, Extended Data Table 2; two-sided MWU, P < 0.01).
“Engraftment in the phase 3 trial was also higher than that observed in patients who received the fixed low-dose regimen in the phase 2 study at all timepoints shared”
ResultsFind in source - supportedReviewers 1, 2VOS significantly altered microbial composition, enriching Firmicutes and reducing C. difficile and opportunistic pathogens.Compositional (NMDS/PERMANOVA), phylum relative abundance (MWU), and genus prevalence (Fisher's exact, FDR < 0.05) analyses directly support this claim.Evidence: NMDS/PERMANOVA (P < 0.001), Firmicutes/Proteobacteria phylum shifts, and genus prevalence with Fisher's exact test (FDR < 0.05), including reduced C. difficile in VOS arm.
“Consistent with the clinical success of VOS, we observe significantly less C. difficile in the VOS arm relative to the placebo arm”
ResultsFind in source - supportedReviewer 1Significant changes in key bioactive metabolites occurred, including depletion of primary bile acids, enrichment of secondary bile acids, and increases in short- and medium-chain fatty acids.Targeted and global metabolomics with MWU comparisons support the metabolite changes in the VOS arm.Evidence: Bile-acid and fatty-acid metabolomics (Fig. 6; MWU P ≤ 0.001 for primary bile acids, P ≤ 0.02 for secondary bile acids, P < 0.05 for fatty acids).
“concentrations of the primary bile acids cholic acid and chenodeoxycholic acid (CDCA) were highest at baseline and remained elevated in the placebo arm relative to the VOS arm through week 2 after dosing (Fig. ; MWU, P ≤ 0.001)”
ResultsFind in source - supportedReviewer 1In vitro, VOS batches produced C. difficile-inhibiting metabolites.The dose-material culture experiments showed production of DCA, LCA, butyrate, valerate, and hexanoate, and the fatty-acid inhibition assays showed dose- and chain-length-dependent C. difficile growth inhibition.Evidence: In vitro dose-material cultures (binary production outcomes) and IC50-based fatty-acid inhibition across three ribotypes (Extended Data Figs. 6, 7).
“All five batches displayed the anticipated bile acid and fatty acid metabolic activities (Extended Data Fig. ).”
ResultsFind in source - supportedReviewer 1These pharmacodynamic findings provide mechanistic insights into how VOS may prevent CDI recurrence.The claim is appropriately hedged ('potential role', 'may act synergistically'), and the mechanistic link is supported by the observed engraftment, compositional, and metabolite changes alongside the phase 3 efficacy result.Evidence: Integrated engraftment, microbiome-composition, and metabolite data from the phase 3 trial, with in vitro confirmation of metabolite production.
“these comprehensive compositional and functional assessments support the multifaceted pharmacological impact of targeted live, microbiota-based therapeutics (in this case, VOS) to replenish Firmicutes richness and abundance and drive subsequent changes in bacterial-derived metabolites”
DiscussionFind in source - supportedReviewer 2Significant changes in key bioactive metabolites occurred, including depletion of primary bile acids, enrichment of secondary bile acids and increases in short-chain and medium-chain fatty acids.Targeted and global metabolomics, plus in vitro confirmation, directly support the reported bile-acid and fatty-acid changes.Evidence: Primary bile acids (cholic acid, CDCA) decreased and secondary bile acids (DCA, LCA) increased in VOS; butyrate, valerate and hexanoate increased.
concentrations of primary bile acids cholic acid and chenodeoxycholic acid (CDCA) were highest at baseline and remained elevated in the placebo arm relative to the VOS arm through week 2 after dosing
Figure 6reviewer’s wording - supportedReviewer 2In vitro, VOS batches produced these C. difficile-inhibiting metabolites.The in vitro batch-culture experiments (metabolite detection in culture supernatant and fatty-acid growth-inhibition assays across three ribotypes) directly support this claim.Evidence: All five dose batches produced DCA, LCA and fatty acids in culture; all tested fatty acids inhibited C. difficile growth in vitro.
“All tested fatty acids were able to slow down or inhibit in vitro growth of C. difficile”
DiscussionFind in source
Efficacy claim is anchored to an adequate endpoint and a meaningful effect.
- ADEQUATESurrogate endpointThe efficacy claim is based on the phase 3 randomized controlled trial's primary endpoint of CDI recurrence at 8 weeks, which is a hard clinical outcome. The paper also reports supportive pharmacodynamic biomarkers (engraftment, bile acids, fatty acids), but the clinical benefit claim does not rest solely on these surrogates.
“only 12% of VOS-treated patients versus 40% of placebo patients recurred by week 8 (relative risk 0.32, P < 0.001)”
- ADEQUATEEffect sizeThe primary effect is a large, statistically significant reduction in clinical recurrence (12% vs 40%, RR 0.32, P<0.001), with an explicit number needed to treat of four, anchoring the effect as clinically material.
“VOS achieved 88% efficacy for prevention of recurrence compared to 60% of placebo and a number needed to treat of four”
Data authenticity concerns
1 finding · worst mediumAn adversarial read for patterns associated with data that may not be genuine: results that look too clean, implausibly large effects, duplicated data or images, and methods that do not match the results reported.
- Other integrity concernAssessed
1 integrity concern flagged (0 high).
- mediumotherTrial NCT02437487 was first submitted to ClinicalTrials.gov on 2015-05-05, after the registered study start date of 2015-05. Retrospective registration means the protocol and outcomes were not on the public record before the study ran, which is what prospective registration exists to establish.
NCT02437487
reviewer’s wording
Reporting gaps
3 findings · worst highRequired detail the manuscript never states — study design, biological variables, ethics approval and consent, key resources, statistical reporting, data and code availability, and overall transparency.
- Statistical reporting gaps (tests, assumptions, effect sizes)Assessed
- Data/code availability incompleteAssessed
- Ethics/consent reporting incompleteAssessed
The paper cites prior work on bile acid and short-chain fatty acid mechanisms of C. difficile inhibition, the phase 1b/phase 2 results, and the hypothesis of suboptimal dosing. The rationale linking prior discordant outcomes to dosing is clearly stated, and the objectives (pharmacokinetic/engraftment comparison and mechanistic microbiome analysis) follow logically. Limitations of prior work (discordant phase 1b vs phase 2 results) are explicitly addressed as the motivation for the higher phase 3 dose.
“These discordant outcomes were hypothesized to be due to suboptimal dosing.”
“we compared the pharmacokinetics of the phase 3 trial to the phase 1b and phase 2 trials to address the hypothesis that different dosing regimens across the VOS clinical development program led to different clinical results.”
“Microbe-mediated conversion of conjugated primary bile acids to secondary bile acids is inhibitory to C. difficile spore germination and growth”
“Microbe-mediated conversion of conjugated primary bile acids to secondary bile acids is inhibitory to C. difficile spore germination and growth”
“This phase 2b study missed its primary efficacy endpoint”
Randomization (1:1), randomization unit (patient), and full blinding (patients, site staff, sponsor) are clearly stated. Eligibility criteria and stratification are detailed, and sample exclusions (low read depth, post-antibiotic exposure, protocol deviations) are described as a form of outlier/data handling. Appropriate controls include the placebo arm, uninoculated media controls, and contamination-control sequencing samples. A priori power analysis is absent for this post hoc analysis, and independent replication of the key findings is not reported, though a strain-based (StrainPhlAn) confirmatory analysis partially strengthens the species-based engraftment result.
“Patients were randomly assigned 1:1 to VOS (approximately 3 × 10 7 spore colony-forming units) or matching placebo administered as four oral capsules once daily over three consecutive days . All patients, site staff and the sponsor were blinded to treatment assignment.”
“eligible adults 18 years of age or older with three or more CDI episodes within 12 months, inclusive of the qualifying acute episode, were enrolled.”
“Samples collected after patient exposure to posttreatment antibiotics were excluded from subsequent analysis to prevent confounding by additional antibiotic treatment”
“All patients, site staff and the sponsor were blinded to treatment assignment.”
“Patients were randomly assigned 1:1 to VOS (approximately 3 × 10 7 spore colony-forming units) or matching placebo”
“Samples collected after patient exposure to posttreatment antibiotics were excluded from subsequent analysis to prevent confounding by additional antibiotic treatment”
Sex (59.9% female) and mean age (65.5 years) are reported for the phase 3 population, with similar data for phase 1b and phase 2. Health status is defined by CDI recurrence criteria. Sex is determined by self-report/health records; both sexes were enrolled, so a sex justification is not required. Race/ethnicity and full comorbidity details are not in this paper but are referenced to Feuerstadt et al. and Cohen et al., so demographics is rated reported_but_inadequate.
“One hundred and eighty-two patients were randomized in the phase 3 trial (59.9% female, mean age 65.5 years; Extended Data Table ).”
“A full description of patient demographics and baseline characteristics, including sex and age, is available in Feuerstadt et al. and Cohen et al.”
“One hundred and eighty-two patients were randomized in the phase 3 trial (59.9% female, mean age 65.5 years”
“Sex was not considered in the clinical trial study design.”
The paper states 'The institutional review board for each study site reviewed and approved the protocol and applicable amendments, and all patients provided written informed consent at screening' — a named approving body and consent that satisfy irb_ethics_statement and informed_consent. However, no recognized regulatory framework (Declaration of Helsinki, GCP, Common Rule) is named; 'The trial followed the CONSORT reporting guideline' addresses reporting, not ethical/regulatory compliance. Because one applicable criterion is inadequate, the dimension is a warn, though the underlying ethics handling is strong.
“The institutional review board for each study site reviewed and approved the protocol and applicable amendments, and all patients provided written informed consent at screening (Supplementary Table ).”
“The trial followed the CONSORT reporting guideline.”
“The institutional review board for each study site reviewed and approved the protocol and applicable amendments, and all patients provided written informed consent at screening”
“The trial followed the CONSORT reporting guideline.”
As a drug/biologic trial, the investigational product is scored under reagents_identified: VOS is named, dosed (3 × 10^7 spore CFU), and its manufacturing described. Software is well identified (MetaPhlAn2, StrainPhlAn version 4, vegan version 2.5-6, dplyr 1.1.2, ggplot2 3.7, ggpubr 0.6.0, reshape2 1.1.4). The in vitro organisms (C. difficile ribotypes with ATCC numbers) are identified. Antibody/cell-line/mycoplasma criteria are not applicable to this study.
“All experiments were carried out with three different C. difficile ribotypes (RT-001, C lostridioides difficile American Type Culture Collection (ATCC) 9689; RT-060, C lostridioides difficile ATCC 43593; RT-087, Clostridioides difficile ATCC 43255)”
“DNA was extracted in-house from patient stool and drug materials using the Omega Mag-Bind Universal Pathogen Kit (Norcross). Libraries were prepared using Illumina DNA Flex kits”
“All experiments were carried out with three different C. difficile ribotypes (RT-001, C lostridioides difficile American Type Culture Collection (ATCC) 9689; RT-060, C lostridioides difficile ATCC 43593; RT-087, Clostridioides difficile ATCC 43255)”
Tests are named (two-sided Mann-Whitney U, PERMANOVA, PERDISP2, Fisher's exact with Benjamini-Hochberg FDR, linear regression R²). Non-parametric tests are appropriately chosen for skewed microbiome data, addressing assumptions. Software/versions are identified. Data presentation is adequate (box plots with median, IQR, and per-group n). However, many p-values are printed only as thresholds (P < 0.001, P < 0.01, P < 0.05), which is imprecise reporting, and effect sizes are reported primarily as p-values with few CIs (only R² values for regressions), so effect_sizes_ci is not_reported. Mathematical plausibility is not independently verifiable from the printed aggregate statistics.
“Engraftment in the phase 3 trial was also higher than that observed in patients who received the fixed low-dose regimen in the phase 2 study at all timepoints shared (Extended Data Table ; two-sided Mann−Whitney U -test (MWU), P < 0.01).”
“PERMANOVA and dispersion tests comparing treatment arms within each timepoint differ significantly in both the location of samples and the size of clusters (Fig. ; P < 0.001).”
“strain-based and species-based engraftment measures correlated with the relationship being stronger in the VOS arm (Extended Data Fig. ; R 2 values at week 1: VOS: 0.64, placebo: 0.13).”
“Engraftment in the phase 3 trial was also higher than that observed in patients who received the fixed low-dose regimen in the phase 2 study at all timepoints shared (Extended Data Table ; two-sided Mann−Whitney U -test (MWU), P < 0.01).”
“In phase 3, only 12% of VOS-treated patients versus 40% of placebo patients recurred by week 8 (relative risk 0.32, P < 0.001).”
“Plots were generated using the following packages: dplyr version 1.1.2, ggplot2 version 3.7, ggpubr version 0.6.0 and reshape2 version 1.1.4.”
The data availability statement names a concrete route: contacting NHScdatarequests@us.nestle.com, with a review process and a 4-week timeframe, which is reported_and_adequate for a clinical dataset with identifiable patient data. However, metagenomics sequencing data (which are potentially depositable in a public repository) are not deposited with accession numbers, and no custom analysis code is shared in a public repository; the tools used are named but not version-controlled in a repo. repository_deposit, accession_numbers, and code_sharing are therefore not_reported, giving 1 of 4 applicable criteria adequate.
“Metabolomics, sequencing and individual-level patient data may be requested for non-commercial purposes by contacting NHScdatarequests@us.nestle.com. All requests will be reviewed by a member of the Nestlé Health Science legal team”
Methods are comprehensive (dosing, sampling, sequencing, metabolomics, in vitro assays). The parent phase 3 trial is registered with ClinicalTrials.gov numbers (NCT03183128, NCT02437487), and CONSORT adherence is stated. Preplanned exploratory microbiome endpoints are described and reported; post hoc deviations are explicitly enumerated. Limitations (few recurrences in VOS arm, relative-abundance nature of sequencing, low donor-batch number) are discussed. Conclusions are appropriately hedged regarding mechanism. Funding (Seres Therapeutics) and competing interests are disclosed.
“Limitations of this study include the limited number of CDI recurrences in the VOS arm, preventing examination of associations between engraftment or metabolites and clinical outcome.”
“ClinicalTrials.gov registrations: NCT02437487 (https://clinicaltrials.gov/study/NCT02437487) and NCT03183128 (https://clinicaltrials.gov/study/NCT03183128) .”
“Limitations of this study include the limited number of CDI recurrences in the VOS arm, preventing examination of associations between engraftment or metabolites and clinical outcome.”
“Seres Therapeutics funded this research.”
Registered (2 IDs: ClinicalTrials.gov). Reporting guideline cited: CONSORT.
Broken references and links
None foundReferences checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.
Checked — nothing surfaced.
Checked 60 references by DOI: 59 verified — 1 no DOI (shown, not verified).
- NO DOIEfficacy and safety of investigational microbiome drug SER-109 for treatment of recurrent Clostridioides difficile infectionNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
4 data/code links checked; 4 live.
- datahttps://clinicaltrials.gov/study/NCT02437487LIVEHTTP 200Resolves, but the content could not be matched to the paper.
- datahttps://clinicaltrials.gov/study/NCT03183128LIVEHTTP 200Resolves, but the content could not be matched to the paper.
- datahttps://clinicaltrials.gov/ct2/show/NCT02437487LIVEHTTP 200Resolves, but the content could not be matched to the paper.
- datahttps://clinicaltrials.gov/ct2/show/NCT03183128LIVEHTTP 200Resolves, but the content could not be matched to the paper.
Copyediting
8 minorWording, consistency and formatting errors that need correcting before submission.
No major wording or formatting errors. 8 minor suggestions below.
8 copyedit issues flagged: mostly consistency, typo, clarity.
- MINORtypoMain, paragraph 1 (VOS description)“rigorously screened heathy donors”→ rigorously screened healthy donorsSpelling error: 'heathy' should be 'healthy'.
- MINORconsistencyMethods, Microbiome and metabolomics profiling“C lostridioides difficile American Type Culture Collection (ATCC) 9689”→ Clostridioides difficile American Type Culture Collection (ATCC) 9689Missing space/letter in 'Clostridioides' within the strain listing; elsewhere spelled correctly.
- MINORclarityResults, VOS treatment leads to changes in metabolites“as observed previously in this disease state (Fig. )”→ as observed previously in this disease stateEmpty figure reference '(Fig. )' with no figure number.
- MINORconsistencyAbstract / Main“P < 0.001) Here in this follow-up post hoc analysis”→ P < 0.001). Here, in this follow-up post hoc analysis,Missing period after the parenthetical and a minor punctuation/run-on issue.
- MINORtypoMain, paragraph 2 (VOS manufacturing description)“rigorously screened heathy donors”→ rigorously screened healthy donorsMisspelling of 'healthy'.
- MINORconsistencyMethods vs Extended Data Fig. 6“RT-060, C lostridioides difficile ATCC 43593 / R-069, ATCC 043593”→ Use a single ribotype label and ATCC identifier consistently across Methods and Extended Data.Ribotype label differs (060 vs 069); ATCC number is the same padded differently.
- MINORtypoMethods, Microbiome and metabolomics profiling“C lostridioides difficile”→ Clostridioides difficileInconsistent/wrong spacing of the genus name in several places.
- MINORconsistencyResults, Patient disposition“71, 66); week 2 (65, 55); week 8 (64, 46); week 24 (51, 40)”→ Verify sample-size strings across figures and Extended Data tables are internally consistent.Sample sizes recur across Figures 4, 5 and several Extended Data figures; minor transcription risk.
The published paper is methodologically sound but has reporting deficiencies that should be addressed via a correction or data/code deposit. An informed reader should weigh the imprecise p-value reporting, missing confidence intervals, absence of custom analysis code, and the retrospective registration of the phase 2 trial. None of these issues invalidate the main conclusions, but they reduce reproducibility and transparency. A correction adding exact p-values, CIs, and a regulatory compliance statement would strengthen the paper.
- 1.HIGHstatisticsReplace p-value thresholds (e.g., 'P < 0.001') with exact p-values (e.g., P = 0.0003) throughout Results, figure legends, and Extended Data tables.
- 2.HIGHstatisticsAdd 95% confidence intervals to all key effect estimates, starting with the phase 3 relative risk (0.32) in the Abstract and Results, and for the engraftment and metabolite comparisons.Confidence intervals convey the precision of estimates and are essential for interpreting effect sizes, which are currently reported only as p-values or R².
- 3.HIGHdata codeDeposit the custom analysis code (downsampling, StrainPhlAn, R plotting scripts) in a version-controlled public repository (e.g., GitHub, Zenodo) with a permanent DOI, and reference it in the Data availability section.Sharing code enables full reproducibility of the computational analyses, which is a core expectation for metagenomics and statistical work.
- 4.HIGHethicsAdd an explicit statement of compliance with a recognized ethical/regulatory framework (e.g., 'conducted in accordance with the Declaration of Helsinki and ICH Good Clinical Practice') in the Methods 'Study overview—ethics' section.The paper currently only mentions CONSORT, a reporting guideline; a regulatory compliance statement is required by most journals and is a standard ethical safeguard.
- 5.HIGHotherAdd a note in the Methods or Discussion acknowledging that trial NCT02437487 was registered retrospectively (submitted to ClinicalTrials.gov on 2015-05-05 after the study start date of 2015-05) and discuss any implications for the interpretation of the phase 2 results.Retrospective registration can introduce bias in outcome reporting; transparency about this limitation is important for informed readers.
- 6.MEDIUMreportingInclude a summary demographic table (or extended data table) with race/ethnicity, comorbidities, and other baseline characteristics in this paper rather than solely referencing the primary publications.Full demographics are essential for assessing generalizability and potential confounding, and referencing external papers places an unnecessary burden on readers.
- 7.MEDIUMotherDescribe the randomization method (e.g., computer-generated random sequence, block/stratified scheme) for the phase 3 trial in the Methods 'trial design' section.The paper currently only states 'randomly assigned 1:1' without specifying the method, which is insufficient for reproducibility.
- 8.MEDIUMdata codeIf consent permits, deposit de-identified metagenomic sequencing data in a controlled-access public repository (e.g., SRA/ENA) with an accession number, and note the access conditions in the Data availability statement.Public deposition of sequencing data is standard practice and would allow independent verification of the metagenomic analyses.
- 9.MEDIUMotherAdd catalog numbers or RRIDs for the Omega Mag-Bind Universal Pathogen Kit and Illumina DNA Flex kits in the Methods 'Microbiome and metabolomics profiling' section.Catalog numbers enable precise identification of reagents, which is important for reproducibility of the experimental protocols.
- 10.MEDIUMcopyeditFix the empty figure reference '(Fig. )' in the Results section 'VOS treatment leads to changes in metabolites' by replacing it with the correct figure number.An empty cross-reference is a clear error that can confuse readers and suggests incomplete editing.
- 11.MEDIUMcopyeditHarmonize the C. difficile ribotype labels and ATCC identifiers between the Methods (RT-060, ATCC 43593) and Extended Data Fig. 6 (R-069, ATCC 043593) to use a single consistent label and identifier.Inconsistent labeling of strains across the paper could lead to misinterpretation of the in vitro results.
- 12.MEDIUMotherState whether any power or sample-size justification informed the post hoc analyses, or explicitly note their exploratory nature and the absence of a formal power calculation in the Statistical analyses section.Clarifying the exploratory nature of the analyses prevents overinterpretation of the post hoc findings.
- 13.LOWcopyeditCorrect the typo 'heathy' to 'healthy' in the Main text (paragraphs 1 and 2) and ensure consistent spelling of 'Clostridioides' throughout the Methods.Typos, even minor ones, can create a negative impression of the manuscript's quality.
- 14.LOWstatisticsBriefly state how test assumptions were handled (e.g., non-parametric tests used due to skewed abundance data) in the Statistical analyses section.Transparency about assumption verification strengthens the statistical reporting and helps readers judge the appropriateness of the tests.
The star rating is the report’s one-glance summary. Every paper starts at 5★ and loses stars for the concrete problems the review finds — so a rating is never a vague average, it’s a running total you can read line by line under “How this rating was calculated.”
- Reporting — 8 dimensionseach dimension that fully fails−½★
- each dimension partially met−¼★
- Statistics · Integrity · Claimseach serious problem−1★
- each medium problem−½★
- Citationseach retracted or unverifiable reference−¼★
- Copyeditonly when the manuscript needs a full edit−½★
The rating never drops below 1★, and a demonstrable critical failure (an impossible statistic, a proven ethics violation) caps it at 1★ on its own — so the stars can never look healthy when the verdict is CRITICAL.
The rating draws on a panel of agents. Three independent Kaimen Rigor reviewers grade the eight dimensions below across several independent passes (the shown verdict is their majority vote — steadier than any single run), isolate the paper’s major claims and check its own evidence backs them, and flag integrity concerns. Alongside them, a citation agent resolves every reference against Crossref, OpenAlex, and Retraction Watch; a statistics agent recomputes reported tests; and rule-based checks verify that declared data/code links actually resolve. Full text is required — an abstract-only submission is not analyzed.
Graded against NIH, MDAR, ARRIVE 2.0, CONSORT, EQUATOR, and RRID guidelines. A dimension that doesn’t apply to the study type is skipped, never penalized.
This Kaimen Rigor review is model-assisted and is not a substitute for formal expert review. It complements human evaluation by surfacing potential methodological concerns — verify each finding against the source.