PMID: 32794312 DOI: 10.1111/andr.12886
- Male factor is regarded as being the cause of up to 50 percent of cases of infertility.
- Studies demonstrate that bacteria can affect sperm function negatively.
- Utilizing the next-generation sequencing (NGS) techniques have provided a better understanding of the human microbiome.
- Dysbiosis has been reported to impact health.
- Dysbiosis is a term for a microbial imbalance on or inside the body, such as an impaired microbiota.
- Evidence regarding the impact of the semen microbiome on sperm function and fertility remains contradictory.
- 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.
- The research included 55 observational studies with 51299 subjects.
- The research included studies identifying bacteria using NGS, culture or polymerase chain reaction.
- The semen microbiome 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 influence a negative effect on sperm quality.
- Bacteriospermia negatively impacted sperm concentration and progressive motility, and DNA fragmentation index.
- Progressive motility refers to sperm that are swimming in a mostly straight line or large circles.
- Sperm DNA fragmentation index reflects the integrity of and the damage to the DNA, the genetic material of the sperm, thereby detecting potential sperm damage, and it is considered a crucial indicator in evaluating semen quality.
- There was an increased prevalence of Ureaplasma urealyticum in infertile men.
- Ureaplasma urealyticum negatively impacted concentration and morphology.
- There was no difference in the prevalence of chlamydia trachomatis between fertile and infertile men and no significant impact on semen parameters.
- Enterococcus faecalis negatively impacted total motility.
- Mycoplasma hominis negatively impacted sperm concentration, progressive motility and morphology.
Moos WH, Faller DV, Harpp DN, Kanara I, Pernokas J, Powers WR, Steliou K (2016). “Microbiota and Neurological Disorders: A Gut Feeling”. BioResearch Open Access. 5 (1): 137–145. doi:10.1089/biores.2016.0010. PMC 4892191. PMID 27274912.
As reviewed in this report, synthetic biology shows potential in developing microorganisms for correcting pathogenic dysbiosis (gut microbiota-host maladaptation), although this has yet to be proven.“