Seminal bacterial composition in patients with obstructive and non‑obstructive azoospermia

Abstract

A number of culture-dependent and -independent studies have reported that the number and significance of bacterial species in semen may have been underestimated. The aim of the present study was to profile the seminal microbiome in patients with obstructive or non-obstructive azoospermia. A high-throughput sequencing method was adopted to sequence genomic DNA extracted from the semen of healthy people (C group), patients with obstructive azoospermia (OA group) and patients with non-obstructive azoospermia (NOA group). The results revealed that Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria species comprised the majority of bacteria in the C (98.14%), OA (98.26%) and NOA (90.96%) groups. Patients in the OA and NOA groups exhibited an increase in Bacteroidetes and Firmicutes, whereas the number of Proteobacteria and Actinobacteria were decreased compared with the C group. A total of 398 common operational taxonomic units were identified, of which 27 belonged to the genus Lactobacillus. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States analysis indicated that the pathogenic species and reduced biodiversity in the semen of patients with azoospermia may result in an increased risk of metabolic, infectious and immune diseases. In the present study, the seminal microbiome of patients with obstructive or non-obstructive azoospermia was explored, which may be useful for developing novel treatments against azoospermia as well as for its diagnosis.

The Disordered Vaginal Microbiota Is a Potential Indicator for a Higher Failure of in vitro Fertilization

“…There is growing evidence that microbes play an important role in human development, physiology, immunity, and nutrition (11) As one of the most important human-microbial habitats, the vaginal secretions and vaginal epithelial cells in vagina provide rich nutrients for the growth of a wide variety of pathogenic (e.g., Gardnerella and Prevotellas) and non-pathogenic (e.g., Lactobacillus) organisms (12,13), of which Lactobacilli can help host to prevent vaginal infection via producing lactic acid, hydrogen peroxide, bacteriocins (14).…”

Evaluation of the potential of chicoric acid as a natural food antioxidant

“…Numerous studies have indicated that intestinal microbes have an important role in human health (20,(29)(30)(31)(32). Therefore, after confirmation of the antioxidant effect of CA, the present study further investigated the potential effect of CA on common beneficial microbes and pathogens in the human microbiota.…”

Microbiota and Human Reproduction: The Case of Male Infertility

“…In particular, Hou et al, based on microbial communities clustering, were able to discriminate six different groups among healthy semen donors [21]. Chen et al, studying azoospermic patients, found a prevalence of the Lactobacillus genus [22], while another study by Monteiro et al, showed a low abundance of Lactobacilli [9]. Mandar et al, comparing the semen microbiome of patients with prostatitis versus controls, found a higher amount of Lactobacilli, and in particular L. iners, in the healthy subjects group [23].…”

“…Balmelli et al, by analyzing 3196 infertile men, identified a correlation between the presence of the Bacteroides ureolyticus and the increased presence of short-tailed spermatozoa [35]. More recently, next generation sequencing-based studies have been carried out to highlight microbial features in semen samples specifically related to infertility [8,9,21,22]. Hou et al did not find significant differences among controls and infertile men, but were able to identify a correlation between the presence of the Anaerococcus and a reduced sperm quality, suggesting that this bacterium may play a role in infertility [21].…”

“…Monteiro et al, analyzing 118 semen samples with different phenotypic features, found that the seminal microbiota in presence of hyperviscosity and oligoasthenoteratozoospermia had an increased abundance of Proteobacteria and a reduction in Lactobacillus with respect to the controls, thus suggesting that these microbial alterations may be related to a poor reproductive outcome [9]. However, Chen et al found a general reduction in biodiversity and an increase in Bacteroidetes and Firmicutes in azoospermic patients with respect to healthy men [22]. Weng et al analyzed 96 infertile men and found three different clusters: Lactobacillus-predominant, Pseudomonas-predominant and Prevotella-predominant, the latter being associated with low-quality sperm [8].…”