Some previous studies have identified bacteria in semen as being a potential factor in male infertility. However, only few types of bacteria were taken into consideration while using PCR-based or culturing methods. Here we present an analysis approach using next-generation sequencing technology and bioinformatics analysis to investigate the associations between bacterial communities and semen quality. Ninety-six semen samples collected were examined for bacterial communities, measuring seven clinical criteria for semen quality (semen volume, sperm concentration, motility, Kruger’s strict morphology, antisperm antibody (IgA), Atypical, and leukocytes). Computer-assisted semen analysis (CASA) was also performed.
Results showed that the most abundant genera among all samples were Lactobacillus (19.9%), Pseudomonas (9.85%), Prevotella (8.51%) and Gardnerella (4.21%). The proportion of Lactobacillus and Gardnerella was significantly higher in the normal samples, while that of Prevotella was significantly higher in the low quality samples. Unsupervised clustering analysis demonstrated that the seminal bacterial communities were clustered into three main groups: Lactobacillus, Pseudomonas, and Prevotella predominant group. Remarkably, most normal samples (80.6%) were clustered in Lactobacillus predominant group.
The analysis results showed seminal bacteria community types were highly associated with semen health. We believe that Lactobacillus is not only a potential probiotic for semen quality maintenance, but also could be helpful in countering the negative influence of Prevotella and Pseudomonas. This is the first study to investigate whole seminal bacterial communities and provides the most comprehensive analysis of the association between bacterial community and semen quality. The study significantly contributes to the current understanding of the etiology of male fertility.
Integrative Systems Biology Lab ( ISBLab ) aims to integrate interdisciplinary approaches for provide the insights into important biological problems and the industrial value of clinical applications. We also enable the development of new biological resources with broad applications, especially in microRNAs, protein modifications and gene regulation. Recently, high-throughput sequencing and microarray technology become our major focus both in scientific research and clinical applications.