Characterization of seminal microbiome associated with semen parameters using next-generation sequencing

To characterize the seminal microbiome associated with normal and abnormal semen parameters, towards the prediction of reproductive health and sperm quality. Despite the association between bacteria and infertility, few studies have looked at the beneficial effects of the seminal microbiome on infertility. The study comprised semen samples from 69 men with normal spermiograms and 166 men with at least 1 abnormal spermiogram parameter from the Institutional IVF Center between October 2019 and October 2022. We hypothesized that the composition of the microbiota may affect semen parameters. To determine the composition of uncultured bacteria, the 16S ribosomal RNA (rRNA) gene was amplified using Oxford Nanopore Technology. Different groups of bacteria were present in the semen samples of patients with normal semen parameters, such as female factor infertility and abnormal sperm parameters. Bacterial communities differed between samples. However, the relative distribution of Lactobacillus and Prevotella in the normal and abnormal semen groups differed (p = 0.05) and was statistically significant. In the abnormal semen group, the incidence of Lactobacillus probiotics was lower and the frequency of Prevotella was higher. Additionally, principal component analysis (PCA) revealed differences in the microbial composition of normal and abnormal semen. In our study, NGS analysis revealed the increased presence of harmful bacteria Prevotella in groups with abnormal semen raises the possibility that certain microbiota may be associated with semen quality and male infertility.