JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):151
Poster Presentation
29^th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263938

P-139. Impacts of increased seminal microbiota on male infertility

Carolina Pinhol Vieira¹, Raquel de Lima Leite Soares Alvarenga², Gleide Fernandes Avelar¹

¹ Universidade Federal de Minas Gerais - Belo Horizonte - MG - Brasil
² Cegonha Medicina Reprodutiva - Belo Horizonte - MG – Brasil

Objective: Male genital tract infections are investigated by assessing physical symptoms and semen quality. However, asymptomatic semen infections are poorly understood, and their identification is not routine in Assisted Human Reproduction clinics. The techniques commonly performed in laboratories are nonspecific, do not track microorganisms, and do not offer individualized solutions and treatments for the cause of infections, potentially impairing proper treatment and affecting the couple's well-being. Therefore, the aim of this study is to investigate the incidence of altered seminal microbiota and how it influences sperm parameters and DNA fragmentation.
Methods: This retrospective study included data obtained from human sperm analysis (n=320) and DNA fragmentation (n=143) from men aged between 20 and 60 years, for investigation of infertility. Semen samples were collected after 2 to 7 days of sexual abstinence. Sperm parameters were analyzed according to the WHO Manual for the Examination and Processing of Human Semen and sperm DNA fragmentation testing was performed using the CANfrag kit. The seminal microbiota was assessed using 10uL of the fresh sample in a Makler chamber under an optical microscope at 400x magnification and qualitatively classified as normal, moderate, or increased.
Results: From 320 samples evaluated, only 17.3% had normal microbiota and 82.7% had altered microbiota (39.3% moderate and 43.4% increased). Regarding the macroscopic evaluation of semen, 25.8% of infected samples were opaque, and only 8.9% of normal samples presented an opaque appearance. We did not observe a significant change in the color of the infected sample, indicating that semen color is not a predictive parameter of the microbiota. In our study, we found that 44% of the samples had total motility below 40%. Surprisingly, 87% of these samples had altered microbiota, while 63% of samples with normal motility had altered microbiota. These data suggests that the increased presence of bacteria in semen may impair the sperm motility. The sperm DNA fragmentation was increased in 49.1% of contaminated samples, while only 26.1% of samples with intact DNA had altered microbiota. This result may help us understand the origin of the infection, indicating that it may come from orchitis or epididymitis, and may be capable of damaging the DNA structure of sperm.
Conclusion: It has been described in the literature that many pathogens can release spermatotoxic substances and pro- inflammatory cytokines, inducing apoptosis, accessory gland dysfunction, hormonal imbalance, production of immobilization factors and impairment of the acrosome reaction, affecting the fertilization capacity of sperm. In our study, we found a correlation between changes in motility and DNA fragmentation and the increased microbiota, consistent with the literature, and a severe incidence of contaminated samples. These data can help us understand the origin of the infection, as it may damage the structure of sperm DNA. Further studies are being carried out to identify the microorganisms present in contaminated seminal samples, investigate the lifestyle habits and symptoms of patients with low seminal quality, how this bacteria increase influences sperm parameters, and the prevalence of infections in the genital tract of the partners of individuals with altered microbiota.