Microbiome Compositions From Infertile Couples Seeking In Vitro Fertilization, Using 16S rRNA Gene Sequencing Methods: Any Correlation to Clinical Outcomes?

Abstract

BackgroundBacterial infections are usually suspected in infertile couples seeking IVF with no clear understanding of the microbial compositions present in the seminal fluids and vaginal niche of the patients. We used next-generation sequencing technology to correlate microbiota compositions with IVF clinical outcomes.MethodsThirty-six couples were recruited to provide seminal fluids and vaginal swabs. Bacterial DNA was extracted, and V4 region of the 16S rRNA was amplified and sequenced in a pair-end configuration on the Illumina MiSeq platform rendering 2 × 150 bp sequences. Microbial taxonomy to species level was generated using the Greengenes database. Linear discriminant analysis (LDA) effect size (LEfSe) was used to identify biologically and statistically significant differences in relative abundance.ResultsSeminal fluid microbiota compositions had lower bacterial concentrations compared with the vagina, but species diversity was significantly higher in seminal fluid samples. Azoospermic subjects had more relative abundance of Mycoplasma and Ureaplasma. In Normospermic semen, Lactobacillus (43.86%) was the most abundant, followed by Gardnerella (25.45%), while the corresponding vaginal samples, Lactobacillus (61.74%) was the most abundant, followed by Prevotella (6.07%) and Gardnerella (5.86%).ConclusionsSemen samples with positive IVF were significantly colonized by Lactobacillus jensenii (P=0.002), Faecalibacterium (P=0.042) and significantly less colonized by Proteobacteria, Prevotella, Bacteroides, and lower Firmicutes/Bacteroidetes ratio compared with semen samples with negative IVF. Vaginal samples with positive IVF clinical outcome were significantly colonized by Lactobacillus gasseri, less colonized by Bacteroides and Lactobacillus iners. This study has opened a window of possibility for Lactobacillus replenishments in men and women before IVF treatment.

Seminal Microbiota of Idiopathic Infertile Patients and Its Relationship With Sperm DNA Integrity

“…The microbiome composition of the samples analyzed in this work comprised the phyla Firmicutes , Proteobacteria , Actinobacteria and Bacteroidetes . This phylum-level composition and its relative abundance was consistent with previous studies ( Mändar et al, 2017 ; Chen et al, 2018 ; Monteiro et al, 2018 ; Baud et al, 2019 ; Yang et al, 2020 ; Lundy et al, 2021 ; Okwelogu et al, 2021 ; Yao et al, 2021 ). When analyzing deeper into family and genus levels, Streptococcus, Staphylococcus and Dialister and its family Veillonellaceae were found as recurrent genera in our samples, in agreement with previous published works, ( Hou et al, 2013 ; Weng et al, 2014 ; Mändar et al, 2017 ; Chen et al, 2018 ; Monteiro et al, 2018 ; Baud et al, 2019 ; Yang et al, 2020 ; Bukharin et al, 2021 ; Lundy et al, 2021 ; Yao et al, 2021 ).…”

“…For the Firmicutes phylum, the three most abundant genera in our sample study, Finegoldia , Peptoniphilus and Anaerococcus, have also been described in several previous studies as highly abundant in seminal microbiota, although none of them has been previously characterized as the most abundant genera ( Hou et al, 2013 ; Weng et al, 2014 ; Mändar et al, 2017 ; Monteiro et al, 2018 ; Baud et al, 2019 ; Yao et al, 2021 ). The relative abundance of Lactobacillus , found in most of our samples, is lower than the abundance found in previous works ( Hou et al, 2013 ; Weng et al, 2014 ; Mändar et al, 2017 ; Chen et al, 2018 ; Baud et al, 2019 ; Amato et al, 2020 ; Yang et al, 2020 ; Okwelogu et al, 2021 ), a fact also reported by Monteiro et al and Lundy et al ( Monteiro et al, 2018 ; Lundy et al, 2021 ) ( Figure 1 ). Finally, to our knowledge this is the first time that the genus Ezakiella has been detected in seminal samples.…”

“…Ralstonia was detected in Chinese populations ( Hou et al, 2013 ; Yao et al, 2021 ) and the abundance of Moraxella was highlighted only by Monteiro ( Monteiro et al, 2018 ). Corynebacterium and Prevotella , the more representative genera of phyla Actinobacteria and Bacteroidetes respectively, are both among the most recurrent bacteria in the literature ( Hou et al, 2013 ; Weng et al, 2014 ; Mändar et al, 2017 ; Chen et al, 2018 ; Monteiro et al, 2018 ; Baud et al, 2019 ; Amato et al, 2020 ; Yang et al, 2020 ; Bukharin et al, 2021 ; Lundy et al, 2021 ; Okwelogu et al, 2021 ; Yao et al, 2021 ).…”

“…Although no definitive consensus has been reached as yet, several authors agree that seminal microbiota is composed of the phyla Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria ( Lundy et al, 2020 ; Tomaiuolo et al, 2020 ; Farahani et al, 2021 ). Specifically, the most commonly identified genera are Lactobacillus , Corynebacterium , Acinetobacter , Prevotella , Enterococcus , Veillonella , Streptococcus , Porphyromonas , Staphylococcus and Pelomonas ( Hou et al, 2013 ; Weng et al, 2014 ; Mändar et al, 2017 ; Chen et al, 2018 ; Monteiro et al, 2018 ; Baud et al, 2019 ; Amato et al, 2020 ; Yang et al, 2020 ; Bukharin et al, 2021 ; Lundy et al, 2021 ; Okwelogu et al, 2021 ; Yao et al, 2021 ).…”

Marking the Profile of the Microflora of the Endometrium and Uterine Cervix in Women as a Potential Factor Determining the Effectiveness of In Vitro Fertilization

“…Indeed, they showed a different percentage of individual bacteria making up the ejaculate microbiome in men, including normospermia, oligospermia, azoospermia, asthenozoospermia, teratozoospermia, oligoasthenozoospermia, and pyospermia. They also found that the most statistically successful IVF procedure was in couples where Lactobacillus jensenii and Faecalibacterium dominated the semen of men, and Lactobacillus gasseri in women [ 32 ].…”