The semen microbiome and its impact on sperm function and male fertility: A systematic review and meta ‐analysis

AbstractBackgroundMale factor is attributable in up to 50% of cases of infertility. In ‐vitro studies demonstrate that bacteria can negatively impact sperm function. The use of next‐generation sequencing (NGS) techniques have provided a better understanding of the human microbiome, and dysbiosis has been reported to impact health. Evidence regarding the impact of the semen microbi ome on sperm function and fertility remains conflicting.Materials and methodsA systematic search was conducted in accordance with the Preferred Reporting Items for Reviews and Meta ‐analysis (PRISMA) statement. The databases MEDLINE, OVID and PubMed were searched to identify English language studies related to the identification of bacteria in the semen of infertile and fertile men, between 1992‐2019. 55 observational studies were included, with 51299 subjects. We included studies identifying bacteria using NGS, culture or polymerase chain reaction (PCR).ResultsThe semen microbiome (SM) was rich and diverse in both fertile and infertile men. Three NGS studies reported clustering of the seminal microbiome with a predominant species. Lactobacillus and Prevotella were dominant in respective clusters. Lactobacillus was associated with improvements in semen parameters. Prevotella appeared to exert a negative effect on sperm quality.  Bacteriospermia negatively impacted sperm concentration and progressive motility (PM), and DNA fragmentation index (DFI) (MD 3.518,95%CI 0.907 to 6.129, p=0.008).Th...
Source: Andrology - Category: Urology & Nephrology Authors: Tags: REVIEW ARTICLE Source Type: research