Bacterial strains of interest in neurological diseases.
| Strain studied | Pathology or disorder studied | Intervention | Mechanism of action | References |
|---|---|---|---|---|
| Bifidobacterium breve | MPTP-induced Parkinson’s disease (PD) in mouse models | 1 × 109 CFU/200 μL of saline | Neuroprotection induced by reduction of neuroinflammation and oxidative stress, maintenance of barriers, modulation of microbiota, increase of SCFAs and neurotrophic factors, improving neurotransmitters and motor function. | Li et al. [56], 2022 |
| Bifidobacterium breve | Mild cognitive impairment in older patients with suspected condition | 2 × 1010 CFU for 24 weeks | It improves cognitive function, especially orientation, possible modulation of inflammation and microglia, decreased brain atrophy, and indirect effects via metabolites and cellular components despite minimal changes in the microbiota. | Asaoka et al. [57], 2022 |
| Bifidobacterium breve | Mild cognitive impairment in older adults | 2.0 × 1010 CFU for 24 weeks | Potential to improve cognitive function through the suppression of inflammation-related genes. | Kobayashi et al. [58], 2019 |
| Bifidobacterium breve | Mild cognitive impairment in older adults | 2 × 1010 CFU/day for 16 weeks | The cognitive benefits may be associated with anti-inflammatory effects, modulation of the inflammatory response, and promotion of hippocampal function. | Xiao et al. [59], 2020 |
| Lactobacillus rhamnosus GG | Noise-induced cognitive deficits and systemic inflammation in rats | 1 × 108 CFU/mL for 56 days | It improves cognitive deficits and reduces inflammation by modulating the gut-brain axis, strengthening the intestinal and blood-brain barrier. In addition, it increases SCFAs and regulates pro-inflammatory cytokines. | Li et al. [60], 2023 |
| Lacticaseibacillus rhamnosus E9 | MPTP-induced PD in a mouse model | 1 × 108 CFU/mouse/day for 15 days | It exerts neuroprotection by preserving dopaminergic neurons, reducing oxidative stress, and strengthening the intestinal barrier. | Aktas et al. [61], 2024 |
| Lactobacillus rhamnosus GG | Cognitive impairment in mice with sepsis | 5 × 109 CFU/mL for 1–3 weeks | It mitigates sepsis-induced cognitive decline by preserving brain-derived neurotrophic factor (BDNF) and p-TrkB in the hippocampus, protecting neuronal survival, and possibly modulating the microbiota-gut-brain axis. | Wang et al. [62], 2024 |
| Lactobacillus rhamnosus GG | Middle-aged and older adults with cognitive impairment | 20 × 109 CFU/day | Modulation of the gut-brain-microbiome axis through immune signaling, vagal pathways, enteroendocrine cells, and microbial metabolites; reduction of inflammatory cytokines and direct influence on neurotransmission and hippocampal pathways with indirect benefits. | Sanborn et al. [63], 2020 |
| Lactobacillus rhamnosus and Bifidobacterium lactis | Healthy older adults, with or without suspected mild cognitive impairment, experiencing age-related cognitive and emotional decline | 3.3 × 109 CFU/day for 10 weeks | Modulation of the gut-brain axis, including immune regulation and neuroprotection, reduction of inflammation, modulation of the hypothalamic-pituitary-adrenal (HPA) axis, improvement of stress and mood, as well as direct effects on neurotransmission, neurogenesis, and synaptic plasticity. | Ruiz-Gonzalez et al. [64], 2025 |
| Lactiplantibacillus plantarum HEAL9 | Cognitive decline and progression of Alzheimer’s disease | 1 × 109 CFU for two months | It improves cognition and intestinal motility, reduces astrogliosis, microgliosis, accumulation of Aβ1–42, and inflammation via inhibition of the NLRP3 inflammasome, as well as the increase of butyrate. | Di Salvo et al. [65], 2024 |
| Lactiplantibacillus plantarum | PD | 6 × 1010 CFU for 2 weeks | It improves motor deficits, modulates neurotransmitters, protects dopaminergic neurons, and reduces oxidative stress. | Lu et al. [66], 2021 |
| Lactiplantibacillus plantarum | PD, specifically in mouse models | 1 × 109 CFU in 200 μL of saline for 28 days | It protects the nigrostriatal pathway by preserving neurons and dopamine, decreases glial activation, neuroinflammation, and oxidative stress, as well as the increase in norepinephrine and neurotrophic factors. | Liao et al. [67], 2020 |
| Lactiplantibacillus plantarum | Patients with Rett syndrome (RTT) carrying MECP2 gene mutations | 6 × 1010 CFU/day | It likely regulates neurotransmitters and increases levels of BDNF, as well as reducing neuroinflammation and systemic oxidative stress. | Wong et al. [68], 2024 |
| Saccharomyces boulardii | Hemiplegic spastic cerebral palsy in murine models | 1 × 107 CFU/day for 9 days | Improvement of behavior and emotional conditions. In addition, reduction in inflammatory processes and modulation of the HPA axis. | Tao et al. [69], 2021 |
| Saccharomyces boulardii | Rotenone-induced PD in a rat model | 1 × 109 CFU/day for 60 days | Protection of dopaminergic neurons. As well as improvement of motor function, modulation of the intestinal immune response, increase in butyrate, and reduction of glial activation, neuroinflammation. | Ipek and Basaloglu [70], 2026 |
| Saccharomyces boulardii | Cognitive impairment associated with antibiotic-induced intestinal dysbiosis in a murine model | 90 mg/kg once a day for 21 days | Prevention of dysbiosis due to antibiotics, normalization of intestinal permeability, reduction of inflammation and oxidative stress, generating protection to hippocampal neurons, reversing cognitive deterioration. | Roy Sarkar et al. [71], 2021 |
| Akkermansia muciniphila | Liver disease and cognitive impairment in a murine model | 1 × 109 CFU/mL in 200 μL | Reduction of inflammation and intestinal permeability, normalizes serotonin levels and increases BDNF, and improves neuroplasticity processes. | Kang et al. [72], 2024 |
| Akkermansia muciniphila | Alzheimer’s disease and cognitive impairment in a murine model | 5 × 109 CFU in 200 μL for 6 months | Optimizes glucose and lipid metabolism, as well as the intestinal barrier. It reduces cortical Aβ, modulates inflammation and insulin resistance, favoring neuroprotection, and improving cognitive function. | Ou et al. [73], 2020 |
| Akkermansia muciniphila | Alzheimer’s disease in a murine model | 1 × 109 CFU for 7 months | Promotes the reduction of microglia activation and inflammation. They improve intestinal transit, memory, and anxiety. | Kunevičius et al. [74], 2025 |
MPTP: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; CFU: colony-forming unit; SCFAs: short-chain fatty acids; p-TrkB: phosphorylated tropomyosin receptor kinase B; Aβ: beta-amyloid; NLRP3: NOD-like receptor family pyrin domain containing 3; MECP2: methyl-CpG-binding protein 2.