Progress in studies of seminal microbiome based on next-generation sequencing
Seminal microbiome plays an important role in male reproductive health,and its composition may be associated with sperm quality,development of oligoasthenospermia,and pregnancy outcomes of assisted reproductive technology.Seminal microbiome may be transmitted to the partner and offspring,and consequently affect female reproduction and the health of offspring.The complete structure of seminal microbiome is difficult to find by conventional bacterial culture due to the length of time taken and restriction of condition.Next-generation sequencing(NGS)can reveal the complete composition of seminal microbiome and help elucidate the com-plex microbial-host interactions based on human physiology and pathophysiology.This review focuses on the composition of seminal mi-crobiome,its relationship with male infertility and the mechanism of its impairing sperm quality based on NGS,and summarizes the re-sults of NGS-based studies on the patterns of bacterial colonization in different anatomical parts of the male reproductive tract.Current studies have revealed a unique diversity of seminal microbiome structures,a close correlation of abnormal seminal microbiome structure with sperm quality and male fertility,and a possible probiotic microbiome in semen capable of supporting health function.So far,the source and composition of seminal microbiome,and its influence on fertility and pregnancy outcome are not yet clear,and the specific mechanism of its diversity affecting sperm needs to be further studied with larger sample sizes and appropriate control specimens.