The relationship between seminal microbiome and male reproductive wellness: a systematic review
Clinical Snapshot
PICO Framework
| P — Population | Males with reproductive health concerns, including infertile men and those with various urogenital conditions |
| I — Intervention | Assessment of seminal microbiome composition and diversity |
| C — Comparator | Fertile controls or baseline microbiome states |
| O — Outcomes | Sperm parameters (motility, concentration, DNA integrity), fertility outcomes, reproductive tract infections, and associated pathological conditions |
Bottom Line
This systematic review identifies significant associations between seminal microbiome composition and male reproductive health, with beneficial genera like Lactobacillus linked to improved sperm parameters and dysbiotic taxa associated with fertility decline. However, the evidence remains largely observational and mechanistic. The authors appropriately acknowledge that standardized assessment methods and longitudinal studies are needed to establish causality before clinical implementation. While probiotics show therapeutic promise, current evidence is insufficient to recommend routine microbiome testing or targeted interventions in male infertility workup. Clinicians should await higher-quality evidence before incorporating microbiome assessment into standard practice, though the biological plausibility supports continued research in this emerging field.
Key Findings
P Value: Not reported
Effect Size: Not quantified - qualitative associations reported
Primary Outcome: Seminal microbiome composition affects sperm parameters and male fertility
Nnt Or Sensitivity: Beneficial genera (Lactobacillus) associated with improved sperm motility, concentration, and DNA integrity; dysbiotic taxa (Prevotella, Pseudomonas, Ureaplasma) associated with parameter decline
Confidence Interval: Not provided
Clinical Application
Limited by lack of standardized microbiome assessment protocols and unclear therapeutic interventions Relevant to Australian fertility clinics and urologists, though specific microbiome testing not currently PBS-funded. May inform future RACGP guidelines on male infertility investigation Men presenting with infertility, recurrent urogenital infections, or reproductive health concerns
Abstract
The seminal microbiome, which is composed of different types of bacteria in semen and seminal plasma, has a significant impact on male reproductive health by changing the quality of semen and fertility. Previously regarded as sterile, the male reproductive tract contains microbes originating from the gastrointestinal tract, reproductive organs, and external sources such as sexual partners. Dysbiosis alters sperm parameters, triggers inflammation and oxidative stress, and is associated with conditions such as infertility, HPV infection, prostatitis, prostate cancer, and azoospermia. This systematic review adhered to the PRISMA 2020 guidelines (with 2025 extensions for reproducibility) and examined studies from PubMed, Scopus, and Science Direct (2015-2025, with prior context), concentrating on human, in vitro, and rodent models. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes are among the most important phyla. Beneficial genera, such as Lactobacillus, improve sperm motility, concentration, and DNA integrity, whereas dysbiotic taxa, such as Prevotella, Pseudomonas, and Ureaplasma, are associated with declines. Sexual activity facilitates bidirectional microbial transfer, modifying diversity and fostering the dysbiosis. Inflammatory cytokines, reactive oxygen species, and metabolic disruptions are all involved in this process. Changes that are specific to a disease, such as higher levels of Fusobacterium in HPV-positive samples, worsen the situation. This review highlights how the microbiome alters sperm function and causes infertility. Standardized methods and long-term studies are needed to prove causality. Probiotics and other therapeutic interventions show promise in restoring balance and boosting fertility.
References
- 1.Bazzar, B., Reshadfar, E., Namdar, P., Pourbagher, D., Bakhtiari Lafmejani, R., & Soleimanzadeh, A. (2026). The relationship between seminal microbiome and male reproductive wellness: a systematic review. Biology of Reproduction. https://doi.org/10.1093/biolre/ioag003
Related Research
Biology of reproduction
Noninvasive pre-transfer identification of women with recurrent implantation failure using a plasma microRNA-based machine learning model
16 July 2026
ACS biomaterials science & engineering
A Review of Biomass-Derived Nanomaterials as Functional Interfaces for Advanced Electrochemical Hormone Detection
14 July 2026
European journal of clinical pharmacology
Clomiphene citrate versus testosterone replacement therapy in male hypogonadism: a systematic review of literature and meta-analysis
13 July 2026
This content is for educational purposes for healthcare professionals only and does not constitute clinical advice. Clinical decisions should be based on individual patient assessment, current guidelines, and appropriate specialist consultation. Editorial Standards · Privacy Policy · Terms of Service