Ischemic stroke patients exhibit distinct gut microbiota profiles and altered functional pathwaysGut Bacteria Show Distinct Patterns in Ischemic Stroke Patients

Frontiers in Medicine Published July 21, 2026 DOI ↗ Editorial oversight: Dr. Ji-eun Park, MD · Brain, Mind & Pain

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Key Takeaway

Note that ischemic stroke patients exhibit distinct gut microbial profiles and pro-inflammatory pathway enrichment.

This systematic review synthesized data from observational studies involving 1,159 patients with ischemic stroke (IS) and 798 healthy controls to evaluate gut microbiota characteristics. The analysis focused on alpha/beta diversity, microbial abundance, and predicted functional pathways in relation to clinical indicators like NIHSS and mRS scores.

Key findings include significant beta diversity separation reported in 18/22 studies. Patients with IS showed increased relative abundance of Proteobacteria and specific genera such as Lactobacillus, Streptococcus, and Parabacteroides. Conversely, Firmicutes and genera including Faecalibacterium, Agathobacter, and Blautia were commonly depleted. Functional analysis revealed an enrichment of pro-inflammatory pathways, such as lipopolysaccharide biosynthesis, alongside a depletion of metabolic and neuroprotective pathways in the IS group.

Clinical correlations were noted for specific taxa: Faecalibacterium abundance correlated negatively with NIHSS and mRS scores, while Lactobacillus and Streptococcus showed positive correlations with stroke severity and inflammatory markers. A primary limitation is that the evidence does not establish whether gut microbiota dysbiosis is a cause, consequence, or exacerbating factor of ischemic stroke. These findings suggest the gut microbiota may serve as a potential biomarker or therapeutic target, though further research is required to determine causality.

This review looked at the gut bacteria of 1,957 people, including over 1,000 patients who had suffered an ischemic stroke. Researchers compared these patients to a group of healthy individuals to see if there were differences in the types of bacteria living in the gut.

The study found that while some general diversity levels were similar, specific types of bacteria were different. For example, certain groups like Proteobacteria were more common in stroke patients, while others like Firmicutes were less common. Some specific bacteria associated with inflammation were higher in stroke patients, while those linked to health and protection were lower.

It is important to note that this was an observational study. Because of this, researchers cannot say if these gut changes caused the stroke or if they happened because of the stroke or other factors. While these findings suggest that gut health could be a way to track or treat stroke in the future, more research is needed to understand the exact role of the gut.

What this means for you:

Stroke patients show specific patterns in gut bacteria, but it is unclear if these changes cause or follow the stroke.

Common questions

What did the study find about gut bacteria in stroke patients?

The review of 1,957 participants found that while overall diversity was similar, specific bacterial groups differed. Proteobacteria were more common in stroke patients, while Firmicutes were less common. Some beneficial types like Faecalibacterium were depleted, and others linked to inflammation were increased.

Are these gut changes a cause of the stroke?

The study cannot confirm if the changes in gut bacteria caused the stroke or were a result of it. It is currently unknown if these differences are a cause, a consequence, or an exacerbating factor of ischemic stroke.

Do these findings mean we can treat strokes with probiotics?

The study suggests that gut microbiota could be a potential target for future treatments. However, because the evidence is from observational data, it does not provide a specific medical treatment or recommendation.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJul 2026

View Original Abstract ↓

BackgroundEmerging evidence implicates the gut microbiota (GM) in the pathogenesis of ischemic stroke (IS). However, systematic evaluations synthesizing evidence on microbial shifts, functional alterations, and clinical correlations are lacking. This study aimed to comprehensively analyze GM characteristics in IS patients versus healthy controls (HC).MethodsA systematic search of PubMed, Web of Science, and Embase was conducted from inception to April 2025. Observational studies comparing GM in IS patients and HC were included. Data on alpha/beta diversity, relative microbial abundance (phylum to species), predicted functional pathways, and microbiota–clinical indicator correlations were extracted. A narrative synthesis summarized the direction and consistency of reported findings.ResultsTwenty-four studies involving 1,957 participants (1,159 IS, 798 HC) were included. The qualitative synthesis revealed no consistent differences in alpha diversity indices between IS and HC, while significant beta diversity separation was frequently reported (18/22 studies). At the phylum level, an increased relative abundance of Proteobacteria and a decreased abundance of Firmicutes were the most consistent findings in IS patients. Key genera frequently enriched in IS included Lactobacillus, Streptococcus, and Parabacteroides, while Faecalibacterium, Agathobacter, and Blautia were commonly depleted. LEfSe analysis confirmed these discriminative taxa. Predicted functional analysis suggested enrichment of pro-inflammatory pathways (e.g., lipopolysaccharide biosynthesis) and depletion of metabolic and neuroprotective pathways in IS. Clinically, Faecalibacterium abundance correlated negatively with NIHSS and mRS scores, while Lactobacillus and Streptococcus showed positive correlations with stroke severity and inflammatory markers.ConclusionIschemic stroke is associated with distinct gut microbial dysbiosis characterized by a pro-inflammatory, opportunistic pathogen-enriched, and butyrate-producer-depleted profile. These alterations correlate with disease severity and are linked to predicted disruptions in microbial metabolic functions. However, whether this dysbiosis is a cause, consequence, or exacerbating factor of IS remains to be determined. The gut microbiota may serve as a potential biomarker and therapeutic target in ischemic stroke.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420251117510, identifier CRD420251117510.

Ischemic stroke patients exhibit distinct gut microbiota profiles and altered functional pathwaysGut Bacteria Show Distinct Patterns in Ischemic Stroke Patients

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Ischemic stroke patients exhibit distinct gut microbiota profiles and altered functional pathwaysGut Bacteria Show Distinct Patterns in Ischemic Stroke Patients

Common questions

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Study Details

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Clinical research that matters. Delivered to your inbox.

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