| Detection of the presence of Lactobacillus spp. in semen samples |
| Eggert-Kruse et al. (1992) |
Germany |
1000 infertile couples. Lactobacillus spp. was detected in 56.8% (531 of 935) of the cervix samples and 13.5% (117 of 869) of the semen samples. |
| Voroshilina et al. (2020) |
Russia |
634 semen samples. Lactobacillus spp. was detected in 125 (19.7%) semen samples. |
| Voroshilina et al. (2021) |
Russia |
227 normooospermia semen samples. Lactobacillus spp. is detected in 26 (11.5%) semen samples. In half of the semen samples classified as normozoospermic, the presence of obligate anaerobes and Lactobacillus spp. was detected. |
| Rivera et al. (2022) |
Colombia |
81 asymptomatic men for urogenital infections. The most frequent microorganism found in semen was Lactobacillus spp. (70%). No association was found between Lactobacillus spp. detection and seminal quality. |
| Intake of prebiotics rich in Lactobacillus spp. |
| Valcarce et al. (2017) |
Spain |
9 asthenozoospermic men. Sperm motility was improved after the treatment, sperm DNA fragmentation and intracellular H2O2 level were reduced after probiotic administration. |
| Maretti & Cavallini (2017) |
Italy |
41 infertile men were divided into consumed prebiotic (Flortec) and control (food starch). The semen parameters (volume, concentration, motility, and sperm morphology) and levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone significantly improved after intake of prebiotic. |
| Helli et al. (2022) |
Iran |
52 men with idiopathic oligoasthenoteratozoospermia. Daily supplementation with 500mg of probiotics for 10 weeks significantly improves semen parameters: volume, total sperm count, sperm concentration, sperm total motility and vitality. |
| Abbasi et al. (2021) |
Iran |
56 infertile men were divided in control group (n=28) and treatment group (n=28). In men who consumed Familact, an increase in sperm quality (concentration, motility, morphology, lipoperoxidation and sperm DNA fragmentation) was observed. |
| Grande et al. (2022) |
Italy |
104 men with primary infertility. A complete eradication with negative semen culture and microbiological analysis on prostatic secretion was observed in 64 of 84 (76.2%) patients receiving probiotics and antibiotics, while only 10 of 20 (50%) patients receiving antibiotics alone. |
| Asadi et al. (2023) |
Iran |
78 men candidates for subinguinal microscopic varicocelectomy. At 3 months after intake of prebiotic, sperm concentration, normal morphology, semen volume and motile sperm were better than the placebo group. |
| in vitro effect of the incubation of Lactobacillus spp. species on sperm physiology |
| Barbonetti et al. (2011) |
Italy |
10 normozoospermic men who consented for fertility problems. Lactobacillus spp. prevented sperm lipid peroxidation induced in vitro by a ferrous ion promoter, which preserves sperm motility and viability. |
| Barbonetti et al. (2013) |
Italy |
6 normozoospermic healthy donors. Soluble factors of Lactobacillus spp. prevented membrane lipid peroxidation of E. coli-exposed spermatozoa, thus preserving their motility. Mitochondrial effects of E. coli are not prevented by the mix of Lactobacillus spp. Lactobacillus spp. could protect spermatozoa in the presence of vaginal disorders by preventing ROS-induced membrane damage. |
| Raad et al. (2023) |
Lebanon |
30 infertile men. Lactobacillus plantarum secretions (108 CFU per mL) protected sperm DNA integrity and motility compared to the freezing medium without Lactobacillus plantarum secretions. |
| Detection of different Lactobacillus spp. species in semen samples from men and their association with different alterations, diseases or conditions |
| Hillier et al. (1990) |
USA |
37 men from infertility clinic. An average of 5.3 microorganisms per ejaculate was found, 16% of the samples had Lactobacillus. |
| Kiessling et al. (2008) |
USA |
29 Men undergoing fertility evaluation and 5 men with vasectomy. Lactobacillus spp. bacterial DNA was detected in 10 semen samples. |
| Ivanov et al. (2009) |
Russia |
108 men: 48 healthy men and 60 men with chronic prostatitis syndrome. Lactobacillus spp. detection in healthy men was 28 (58.3%, 3.5±0.5 mean bacterial count log 10 CFU/mL), while in patients with prostatitis, it was 20 (33.3% of men) with 3.1±0.2 mean bacterial count log 10 CFU/mL. |
| Weng et al. (2014) |
Taiwan |
96 men with primary infertility. The most abundant species of bacteria in semen are Lactobacillus iners (14.09%). Lactobacillus crispatus was not only associated with sperm elongation and with Kruger’s strict morphology. |
| Chen et al. (2018) |
China |
The fertile control (n=5) group, the obstructive azoospermia (n=6) group and the non-obstructive azoospermia (n=6) group. 398 common operational taxonomic units were identified, of which 27 belonged to Lactobacillus spp. (6.79% in the fertile group), whereas it accounted for 17.98% and 17.24% in the obstructive and no obstructive azoospermia groups, respectively. |
| Mändar et al. (2017) |
Estonia |
67 men: 21 with chronic prostatitis and 46 controls. The most remarkable difference between the groups appeared in the counts of Lactobacillus spp. that were higher in healthy men than prostatitis patients (median 27% vs. 20.2%, p=0.05), especially on behalf of Lactobacillus iners (14.2% vs. 9.8%, p=0.013). |
| Monteiro et al. (2018) |
Portugal |
89 cases and 29 controls. Lactobacillus spp. was found at very low abundances in all pooling samples, with the highest proportion registered in pool control (0.6%) and the lowest in pool hyperviscosity (>0.1%). |
| Amato et al. (2020) |
Italy |
23 couples. Relative abundance of Lactobacillus spp. was performed for the seminal microbiome, revealing differences in the relative abundance of Lactobacillus spp. among the cohort of idiopathic infertile men. |
| Baud et al. (2019) |
Switzerland |
26 men with normal semen analysis and 68 men with at least one anormal sperm parameter. The relative abundance of Lactobacillus spp. was greater in samples with normal sperm morphology. |
| Yang et al. (2020) |
China |
159 study participants: 22 patients with oligoasthenospermia, 58 patients with asthenospermia, 8 patients with azoospermia, 13 patients with oligospermia, and 58 healthy controls.Lactobacillus spp. was among the most abundant genera commonly found in seminal plasma. |
| Štšepetova et al. (2020) |
Estonia |
50 infertile men. The most abundant genera of bacteria in the semen before washing (73.3%), and IVF culture solution (35.5%) was Lactobacillus spp. |
| Motamedifar et al. (2020) |
Iran |
350 men: 200 infertile and 150 fertile men. The prevalence of bacteriospermia in the semen of the infertile group was significantly higher than that in the fertile group (48% vs. 26.7%, p<0.001). Moreover, bacteriospermia among the infertile group was associated with higher abnormality in concentration, motility, and sperm morphology (p<0.001). In the control group, Lactobacillus spp. (17.3%) was the most isolated bacteria. |
| Pochernikov et al. (2020) |
Russia |
210 men in two groups, Control group: 105 men without Lactobacillus spp. in the ejaculate and Treatment group 105 men with the presence of Lactobacillus spp. in semen. Lactobacillus spp. is associated with oligoasthenoteratozoospermia (p<0.01), decreased sperm concentration (p=0.01), decreased sperm motility (p<0.01) and morphological abnormalities (p<0.01). |
| Okwelogu et al. (2021) |
Nigeria |
36 infertile couples. Lactobacillus spp. Was more abundant bacteria in semen and vaginal swabs. The family taxa Lactobacillaceae and the Lactobacillus genus were significantly higher in the vaginal swabs than in the semen (61.7 vs. 43.9%). The semen samples of men with positive IVF clinical outcomes were significantly colonized by the Lactobacillus jensenii. |
| Yao et al. (2022) |
China |
87 seminal samples: 33 with a normal seminal leukocyte count and 54 samples with leukocytospermia, 48.1% of men with leukocytospermia had Lactobacillus spp. |
| Garcia-Segura et al. (2022) |
Spain |
56 participants: 14 controls healthy normozoospermic semen donors with no infertility diagnosis and 42 idiopathic normozoospermic infertile patients. seminal microbiota was mainly composed of four phyla: Firmicutes (59%), Proteobacteria (19%), Actinobacteria (8%), and Bacteriodetes (5%). |
| Puerta Suárez et al. (2022) |
Colombia |
10 chronic prostatitis-like syndrome and 11 fertile donors. The control group had more Lactobacillus spp in the semen (58%) compared to the prostatitis group (20%). |
| Koort et al. (2023) |
Estonia |
Couples with assisted reproductive technology procedures (n=97) and fertile couples (n=12). The prevalence of Lactobacillus spp. was lower in semen samples from assisted reproduction techniques men. |
| Cao et al. (2023) |
China |
53 men: 12 controls with normal semen parameters, 12 asthenozoospermia, 6 with oligozoospermia, 9 with several oligozoospermia or azoospermia, and 14 with hyperviscosity. Lactobacillus spp. is positively correlated with sperm concentration and total sperm count. |
| Saldarriaga López et al. (2024) |
Colombia |
22 samples from men with symptoms of chronic prostatitis and 31 asymptomatic men (control group). The volunteers from the group of men with symptoms of chronic prostatitis presented less frequently the DNA of A. vaginae (4.4% vs. control group 9.7%), G. vaginalis (45.5% vs. control group 54.8%), L. crispatus (9.1% vs. control group 16.1%) and L. iners (45.5% vs. control group 58.1%). |
| Osadchiy et al. (2024) |
USA |
73 men: 42 with normal semen analysis and 31 with anormal semen analysis. Participants with normal sperm motility showed a lower abundance of Lactobacillus iners (p=0.0464) than those with abnormal sperm motility, mean proportion was 9.4% vs. 2.6%. |
| Vajpeyee et al. (2024) |
India |
69 men with normal semen parameters and 166 men with at least 1 normal parameter. The relative distribution of Lactobacillus spp. and Prevotella in the normal and abnormal semen groups were different. In the abnormal semen group, the incidence of Lactobacillus spp. probiotics was lower, and the frequency of Prevotella was higher. |