Microbiota of male genital tract: Impact on the health of man and his partner

Comparison of the urinary microbiome in men who have sex with men with and without Chlamydia trachomatis infection

PURPOSE

The urinary tract is colonized by microbial communities that impact urinary health. Previous studies have suggested that the bacterial composition of the male urinary microbiota is related to STIs. This study assessed the bacterial composition of the urinary microbiome in South African MSM with and without C. trachomatis.

METHODS

This study used urine samples from MSM attending care at the King Edward VIII hospital and the Aurum Institute in Durban, South Africa. A total of 200 samples were tested for C. trachomatis infection using the Applied Biosystems™ TaqMan® Assays. Urinary microbiomes of 23 samples were characterized using 16 S rRNA (V3 and V4) gene sequencing on the Illumina MiSeq platform.

RESULTS

Bacterial taxonomic analysis showed a high abundance of Streptococcus, Corynebacterium, and Staphylococcus in all the sequenced samples. Moreover, Prevotella and Lactobacillus were detected in urine samples of MSM. Alpha diversity metrics showed a slight increase in microbial diversity in C. trachomatis positive samples; however, this was not significant (ANOVA, P > 0.05). Principal coordinates analysis (PCoA) showed that the microbiome of C. trachomatis infected MSM was not clearly different from those uninfected. Distinct bacterial communities were not detected between positive and negative samples (PERMANOVA F1,22= 1.0284, R2 = 0.047%, P = 0.385).

CONCLUSION

Most microbiome studies on MSM to date have focused on the gut microenvironment. Few studies, however, have provided data regarding the normal composition of the male urethral microbiomes or if these microbiomes are associated with male STIs. This study adds to the growing body of knowledge highlighting the urinary microbiome in MSM.

The elusive male microbiome: revealing the link between the genital microbiota and fertility. Critical review and future perspectives

There is a growing focus on understanding the role of the male microbiome in fertility issues. Although research on the bacterial communities within the male reproductive system is in its initial phases, recent discoveries highlight notable variations in the microbiome's composition and abundance across distinct anatomical regions like the skin, foreskin, urethra, and coronary sulcus. To assess the relationship between male genitourinary microbiome and reproduction, we queried various databases, including MEDLINE (available via PubMed), SCOPUS, and Web of Science to obtain evidence-based data. The literature search was conducted using the following terms "gut/intestines microbiome," "genitourinary system microbiome," "microbiome and female/male infertility," "external genital tract microbiome," "internal genital tract microbiome," and "semen microbiome." Fifty-one relevant papers were analyzed, and eleven were strictly semen quality or male fertility related. The male microbiome, especially in the accessory glands like the prostate, seminal vesicles, and bulbourethral glands, has garnered significant interest because of its potential link to male fertility and reproduction. Studies have also found differences in bacterial diversity present in the testicular tissue of normozoospermic men compared to azoospermic suggesting a possible role of bacterial dysbiosis and reproduction. Correlation between the bacterial taxa in the genital microbiota of sexual partners has also been found, and sexual activity can influence the composition of the urogenital microbiota. Exploring the microbial world within the male reproductive system and its influence on fertility opens doors to developing ways to prevent, diagnose, and treat infertility. The present work emphasizes the importance of using consistent methods, conducting long-term studies, and deepening our understanding of how the reproductive tract microbiome works. This helps make research comparable, pinpoint potential interventions, and smoothly apply microbiome insights to real-world clinical practices.

Microbial biomarkers as indicators of sperm viability in an insect

Our understanding of microbial variation in male reproductive tissues is poorly understood, both regarding how it varies spatially across different tissues and its ability to affect male sperm and semen quality. To redress this gap, we explored the relationship between male sperm viability and male gut and reproductive tract microbiomes in the Pacific field cricket, Teleogryllus oceanicus. We selected cohorts of males within our populations with the highest and lowest natural sperm viability and characterized the bacterial microbiota present in the gut, testes, seminal vesicle, accessory glands and the spermatophore (ejaculate) using 16S ribosomal RNA gene metabarcoding. We identified bacterial taxa corresponding to sperm viability, highlighting for the first time an association between the host's microbial communities and male competitive fertilization success. We also found significant spatial variation in bacterial community structure of reproductive tissue types. Our data demonstrate the importance of considering the microbial diversity of both the host gut and reproductive tract when investigating male fertility in wildlife and potentially human clinical settings.

Different Prostatic Tissue Microbiomes between High- and Low-Grade Prostate Cancer Pathogenesis

Numerous human pathologies, such as neoplasia, are related to particular bacteria and changes in microbiome constituents. To investigate the association between an imbalance of bacteria and prostate carcinoma, the microbiome and gene functionality from tissues of patients with high-grade prostate tumor (HGT) and low-grade prostate tumor (LGT) were compared utilizing next-generation sequencing (NGS) technology. The results showed abnormalities in the bacterial profiles between the HGT and LGT specimens, indicating alterations in the make-up of bacterial populations and gene functionalities. The HGT specimens showed higher frequencies of Cutibacterium, Pelomonas, and Corynebacterium genera than the LGT specimens. Cell proliferation and cytokine assays also showed a significant proliferation of prostate cancer cells and elevated cytokine levels in the cells treated with Cutibacterium, respectively, supporting earlier findings. In summary, the HGT and LGT specimens showed differences in bacterial populations, suggesting that different bacterial populations might characterize high-grade and low-grade prostate malignancies.

Male Tract Microbiota and Male Infertility

In recent years, several studies have analyzed the composition of the male genital tract microbiota and its changes in infertility or in different situations associated with infertility. The aim of this narrative review is to obtain more insight on this topic; in particular, to describe actual evidence about changes in the semen microbiota in patients with infertility, male tract infections, or HPV infections. In semen, an increase in semen Prevotella spp. is associated with oligozoospermia and with obesity-associated asthenozoospermia; an increase in Pseudomonas is more frequently associated with asthenozoospermia and oligozoospermia; a reduction in Lactobacilli spp. (namely in Lactobacillus crispatus) may represent a marker of low semen quality. However, an increase in Lactobacillus iners is considered a risk factor for a reduced sperm concentration. In patients with prostatitis, there is a reduction in Lactobacillus spp. and an increase in Streptococcus spp., opening important perspectives about the role of probiotic treatments in these patients. Finally, an increase in Fusobacteria spp. was observed in patients with an HPV infection. In the conclusion, we underline the interactions between the seminal and vaginal microbiota, so that further studies should focus on the "couple genital microbiota".

Next-Generation Sequencing to Elucidate the Semen Microbiome in Male Reproductive Disorders

Mean sperm counts are declining at an accelerated rate and infertility is increasingly becoming a public health concern. It is now understood that human semen, previously considered to be sterile, harbours its own specific microbiome. Via activated leucocytes and the generation of reactive oxygen species, bacteria have the capability of evoking an immune response which may lead to sperm damage. Men with infertility have higher rates of both reactive oxygen species and sperm DNA damage. Due to the lack of sensitivity of routine culture and PCR-based methods, next-generation sequencing technology is being employed to characterise the seminal microbiome. There is a mounting body of studies that share a number of similarities but also a great range of conflicting findings. A lack of stringent decontamination procedures, small sample sizes and heterogeneity in other aspects of methodology makes it difficult to draw firm conclusions from these studies. However, various themes have emerged and evidence of highly conserved clusters of common bacteria can be seen. Depletion or over-representation of specific bacteria may be associated with aberrations in traditional and functional seminal parameters. Currently, the evidence is too limited to inform clinical practice and larger studies are needed.

Trichomonas vaginalis adherence phenotypes and extracellular vesicles impact parasite survival in a novel in vivo model of pathogenesis

Trichomonas vaginalis is a human infective parasite responsible for trichomoniasis-the most common, non-viral, sexually transmitted infection worldwide. T. vaginalis resides exclusively in the urogenital tract of both men and women. In women, T. vaginalis has been found colonizing the cervix and vaginal tract while in men it has been identified in the upper and lower urogenital tract and in secreted fluids such as semen, urethral discharge, urine, and prostatic fluid. Despite the over 270 million cases of trichomoniasis annually worldwide, T. vaginalis continues to be a highly neglected organism and thus poorly studied. Here we have developed a male mouse model for studying T. vaginalis pathogenesis in vivo by delivering parasites into the murine urogenital tract (MUT) via transurethral catheterization. Parasite burden was assessed ex-vivo using a nanoluciferase-based gene expression assay which allowed quantification of parasites pre- and post-inoculation. Using this model and read-out approach, we show that T. vaginalis can be found within MUT tissue up to 72 hrs post-inoculation. Furthermore, we also demonstrate that parasites that exhibit increased parasite adherence in vitro also have higher parasite burden in mice in vivo. These data provide evidence that parasite adherence to host cells aids in parasite persistence in vivo and molecular determinants found to correlate with host cell adherence in vitro are applicable to infection in vivo. Finally, we show that co-inoculation of T. vaginalis extracellular vesicles (TvEVs) and parasites results in higher parasite burden in vivo. These findings confirm our previous in vitro-based predictions that TvEVs assist the parasite in colonizing the host. The establishment of this pathogenesis model for T. vaginalis sets the stage for identifying and examining parasite factors that contribute to and influence infection outcomes.

The microbiome and male infertility: looking into the past to move forward

The human body harbours trillions of microbes, and their influence on human health has been explored in many parts of the human body, including the male reproductive system. From routine culturing to polymerise chain reaction (PCR) and high throughput DNA sequencing, several studies have identified bacteria in the male reproductive system. In this review, we discuss the past and current literature surrounding the testicular and semen microbiome in correlation with male infertility. We further highlight the potential benefits of probiotics as an alternative therapeutic option for male infertility. Although not conclusive, emerging data are indicating potential implications of certain bacterial members on male fertility. There is a general agreement on the negative impact of some pathogenic bacterial species on semen parameters, including sperm counts, motility, morphology, and DNA integrity. On the other hand, Lactobacillus, known as a human-friendly bacteria, has shown protective effects on semen parameters, which makes it a potentially good probiotic. In order to confirm the findings of previous studies, more clinical studies with larger sample sizes and the right controls are needed.

Biochemical Recurrence in Prostate Cancer Is Associated with the Composition of Lactobacillus: Microbiome Analysis of Prostatic Tissue

Many human pathologies, such as malignancy, are linked with specific bacteria and changes in the constituents of the microbiome. In order to examine the association between an imbalance of bacteria and prostate carcinoma, a comparison of the microbiomes present in patients with biochemical recurrence (BCR) or NO BCR (NBCR) was performed. Additionally, 16S rRNA-based next-generation sequencing was applied to identify the bacterial profiles within these tumors in terms of the bacteria and operational genes present. The percentage average taxonomic composition between the taxa indicated no difference between BCR and NBCR. In addition, alpha and beta diversity indices presented no distinction between the cohorts in any statistical method. However, taxonomic biomarker discovery indicated a relatively higher population of Lactobacillus in the NBCR group, and this finding was supported by PCR data. Along with that, differences in the operational activity of the bacterial genes were also determined. It is proposed that the biochemical recurrence was linked to the quantity of Lactobacillus present. The aim of this study was to investigate the microbiome involved in prostate carcinoma and the potential association between them.

It's all relative: analyzing microbiome compositions, its significance, pathogenesis and microbiota derived biofilms: Challenges and opportunities for disease intervention

Concept of microorganisms has largely been perceived from their pathogenic view point. Nevertheless, it is being gradually revisited in terms of its significance to human health and now appears to be the most dominant force that shapes the immune system of the human body and also determines an individual's predisposition to diseases. Human inhabits bacterial diversity (which is predominant among all microbial communities in human body) occupying 0.3% of body mass, known as microbiota. On birth, a part of microbiota that child obtains is essentially a mother's legacy. So, the review was initiated with this critical topic of microbiotal inheritance. Since, each body site has distinct physiological specifications; therefore, they contain discrete microbiome composition that has been separately discussed along with dysbiosis-induced pathologies originating in different body organs. Factors affecting microbiome composition and may cause dysbiosis like antibiotics, delivery, feeding method etc. as well as the strategies that immune system adopts to prevent dysbiosis have been highlighted. We also tried to bring into attention the topic of dysbiosis induced biofilms, that enables cohort to survive stresses, evolve, disseminate and infection resurgence that is still in dormancy. Eventually, we put spotlight on microbiome significance in medical therapeutics. We didn't merely confine article to gut microbiota, that is being studied more extensively. Numerous community forms at diverse body sites are inter-related, and being exposed to awfully variable perturbations appear to be challenging to evaluate perturbation risks holistically. All aspects have been elaborately discussed to achieve a global depiction of human microbiota in order to meet urgent necessity for protocol standardisation. Demonstrates that environmental challenges (antibiotic use, alterations in diet, stress, smoking etc.) might cause dysbiosis i.e. transition of healthy microbiome composition to the one in which pathogenic microorganisms become more abundant, and eventually results in an infected state.

Malignant Prostate Tissue Is Associated with Different Microbiome Gene Functions

Specific microorganisms and changes in the constituents of the microbiome are linked with pathologies in humans, such as malignancy. Within the prostate, certain bacterial communities may locate advantageous conditions and establish themselves, thus outperforming alternative species. In this study, a comparison of malignant (MT) and benign prostate tissues (BT) or benign prostate hyperplasia (BPH) was performed in order to delineate the respective microbiomes in each sample type and to determine their pertinence to prostatic tumourigenesis. Specimens of MT (n = 26) and PT (n = 13)/BPH (n = 10) were acquired from patients. No variations in the make-up of the microbiome were seen when MT and PT specimens were compared. Changes in the bacterial constituents and functional genes were seen in the specimens obtained from patients with MT when contrasted against samples from those with BPH. Pelomonas was the genus with the highest abundance in MT specimens. It is proposed that dissimilar microbiome gene functions are present in the contexts of MT and PT samples.

Microbiome in Male Genital Mucosa (Prepuce, Glans, and Coronal Sulcus): A Systematic Review

The human body represents a complex and diverse reservoir of microorganisms. Although the human microbiome remains poorly characterized and understood, it should not be underestimated, since recent studies have highlighted its importance in health. This is especially evident when considering microbiota in the male reproductive system, responsible for men’s fertility and sexual behavior. Therefore, the aim of this systematic review is to provide an overview of the microbial communities of the healthy male genital mucosa and its role in disease. This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was limited to the English language and studies published until August 2022 that included culture-independent techniques for microbiome characterization in male genital mucosa. Ten articles were included. The bacterial composition of the male genital mucosa consists of several genera including Prevotella, Finegoldia, Peptoniphilus, Staphylococcus, Corynebacterium, and Anaerococcus, suggesting that the male genital microbiome composition shows similarities with the adjacent anatomical sites and is related with sexual intercourse. Moreover, male circumcision appears to influence the penile microbiome. Despite the lack of knowledge on the male genital mucosa microbiome in disease, it was reported that Staphylococcus warneri and Prevotella bivia were associated with balanoposthitis, whereas Enterobacteriaceae, Prevotella, and Fusobacterium were more abundant in male genital lichen sclerosus. The limited data and paucity of prospective controlled studies highlight the need for additional studies and established criteria for sampling methods and the microbiome assay procedure. Such a consensus would foster the knowledge about the composition of the genital microbiome of healthy males and its role in disease.

The Urethral Microbiota of Men with and without Idiopathic Urethritis

Nongonococcal urethritis (NGU) is a common genital tract syndrome in men, and up to 50% of cases are considered idiopathic, i.e., no etiological agent is identified. This poses challenges for clinicians in the diagnosis and treatment of NGU and often results in antibiotic misuse and overuse. Therefore, to identify potential infectious causes of urethritis and inform clinical management of urethritis cases, we characterized and compared the urethral microbiota of men with and without idiopathic urethritis. Participants were derived from a case-control study that examined viral and bacterial pathogens and sexual practices associated with NGU. Men with NGU who tested negative for established causes of NGU (Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, adenoviruses, herpes simplex virus [HSV]-1, and/or HSV-2) were classified as idiopathic cases, and the controls were men reporting no current urethral symptoms. Men provided a urine sample that was used to characterize the urethral microbiota using 16S rRNA gene sequencing. Bacterial taxa associated with idiopathic urethritis were identified using analysis of compositions of microbiomes with bias correction. When stratified by sex of sexual partner, we found that the abundance of Haemophilus influenzae was significantly increased in men who have sex with men with idiopathic urethritis, and the abundance of Corynebacterium was significantly increased in men who have sex with women with idiopathic urethritis. Other taxa, including Ureaplasma, Staphylococcus haemolyticus, Streptococcus pyogenes, Escherichia, and Streptococcus pneumoniae/pseudopneumoniae, dominated the urethral microbiota of idiopathic urethritis cases but not controls, suggesting that these organisms may also contribute to urethritis. Importantly, the taxa we identified represent biologically plausible causes of urethritis and should be prioritized for future study.

Updates on Sexually Transmitted Urethro-cystitis

Purpose of Review

We performed recent literature review with the aim to address the updates in diagnosis and management of sexually transmitted urethro-cystitis.

Recent Findings

There are multiple, recently published studies that collectively lead to an organized stepwise plan for diagnosis and management of sexually transmitted urethro-cystitis.

Summary

Sexually transmitted urethro-cystitis is a common health condition that can be managed efficiently if the appropriate steps are taken in diagnosis and management.

The effect of probiotics on immunogenicity of spermatozoa in couples suffering from recurrent spontaneous abortion

Background

Impaired spermatozoa immunogenicity can result in pregnancy complications such as recurrent spontaneous abortion (RSA). Given that spermatozoa contact with microbiota, it is possible that inappropriate microbiota composition in the reproductive tract could result in the alteration of spermatozoa antigenicity. Probiotics, as a representative of microbiota, may therefore have a beneficial effect on this altered immunogenicity. The objective of this study was to determine the effect of probiotics on spermatozoa immunogenicity.

Methods

Twenty-five fertile couples and twenty-five RSA couples were included in this study. Spermatozoa were purified and treated with probiotics. Untreated and probiotic treated spermatozoa were evaluated for human leukocyte antigen (HLA) class I & II expression by flow cytometry. Untreated and probiotic treated spermatozoa were also cocultured with the wife’s peripheral blood mononuclear cells (PBMC) for 12 days. Then, the supernatant was assessed for IgG and APCA by enzyme-linked immunosorbent assay (ELISA) and complement-dependent cytotoxicity (CDC) assay respectively.

Results

Probiotic treatment of spermatozoa leads to an increase of HLA class I & II expression in both the fertile and RSA groups. The probiotic treatment resulted in a decrease in both IgG and APCA in the fertile group, but an increase in both IgG and APCA in the RSA group.

Conclusions

The results of this study suggest that a supplementary probiotic treatment may be useful in couples suffering from RSA with an immunologic cause, because it improves disturbed HLA expression on spermatozoa and improves disturbed APCA and IgG production in the presence of spermatozoa.

Molecular Regulatory Mechanisms Drive Emergent Pathogenetic Properties of Neisseria gonorrhoeae

Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, with an estimated 87 million annual cases worldwide. N. gonorrhoeae predominantly colonizes the male and female genital tract (FGT). In the FGT, N. gonorrhoeae confronts fluctuating levels of nutrients and oxidative and non-oxidative antimicrobial defenses of the immune system, as well as the resident microbiome. One mechanism utilized by N. gonorrhoeae to adapt to this dynamic FGT niche is to modulate gene expression primarily through DNA-binding transcriptional regulators. Here, we describe the major N. gonorrhoeae transcriptional regulators, genes under their control, and how these regulatory processes lead to pathogenic properties of N. gonorrhoeae during natural infection. We also discuss the current knowledge of the structure, function, and diversity of the FGT microbiome and its influence on gonococcal survival and transcriptional responses orchestrated by its DNA-binding regulators. We conclude with recent multi-omics data and modeling tools and their application to FGT microbiome dynamics. Understanding the strategies utilized by N. gonorrhoeae to regulate gene expression and their impact on the emergent characteristics of this pathogen during infection has the potential to identify new effective strategies to both treat and prevent gonorrhea.

Microbial community signatures for estimation of postmortem time intervals

The human body provides a complex ecosystem for symbiotic habitation of a huge number of microorganisms. These commensal microorganisms provide a huge benefit to the living host by acting against many deadly infections. Once the host dies, many changes in the complex ecosystem of the human body take place. The personalized microbes of a human body undergo successional change as many exogenous microbes attack the nutrient-rich cadaver after death. The succession pattern change of microbes in human cadaver allows postulating different models for estimation of Postmortem time interval (PMI). Estimation of PMI has a broad prospect from the criminal investigation point of view. Though many techniques are being used nowadays to estimate PMI, all of them have their pros and cons. With the advent of advanced molecular biological techniques, studies on the thanatomicrobiome of a human cadaver have gained pace and provide a superior alternative for conventional methods of PMI estimation. This chapter summarizes the recent advancements in the changes in signature microflora postmortem with change in human microenvironment to postulate a consensus model for estimation of PMI.

The Semen Microbiome and Semen Parameters in Healthy Stallions

Simple Summary

Stallion infertility is a major cause of concern in the horse industry. Despite zootechnics advances, sub- or infertile animals appear in stud farms without a toxic, genetic, or nutritional reason. Recent research in human andrology has opened the door for a new, plausible factor that affects sperm quality: seminal microflora. In recent years, there has been an increasing amount of evidence regarding the relationship between different seminal flora compositions and male fertility. However, little has been studied in veterinary science, including horses. Therefore, the objective of this study was to examine associations with the presence of bacteria families in horse semen with five sperm quality parameters: concentration, total number of spermatozoa, total and progressive sperm motility, and DNA fragmentation. Our study detected a correlation between the presence of the Peptoniphilaceae family and higher total motility and the presence of Clostridiales Incertae Sedis XI and lower progressive motility. These changes in seminal flora may contribute to the idiopathically poorer sperm quality in certain animals. Although further mechanisms behind bacteria–spermatozoa interactions are unknown, these associations are already leading to a new therapeutic approach to infertility: the use of prebiotics, which has already yielded promising results in human andrology.

Abstract

Despite the advances in reproductive technology, there is still a considerable number of low sperm quality cases in stallions. Recent studies in humans have detected several seminal microflora–spermatozoa associations behind some idiopathic infertility cases. However, no studies are available on horses, and there is limited information on the microflora present in stallion ejaculates. Accordingly, the objective of this study was to examine associations to the presence of bacteria families with five sperm quality parameters: concentration, total number of spermatozoa, total and progressive motility, and DNA fragmentation. Samples were cryopreserved after their extraction. High-speed homogenization using grinding media was performed for cell disruption. Family identification was performed via 16S rRNA sequencing. Bacterial families were only considered if the relative abundance was higher than 1%. Only two families appeared to have a correlation with two sperm quality parameters. Peptoniphilaceae correlated positively with total sperm motility, whereas Clostridiales Incertae Sedis XI correlated negatively with progressive motility. No significant differences were found for the rest of the parameters. In conclusion, the seminal microbiome may affect spermatozoa activity. Our findings are based on statistical associations; thus, further studies are needed to understand the internal interactions between seminal flora and cells.

Characterization of the seminal bacterial microbiome of healthy, fertile stallions using next-generation sequencing

High-throughput sequencing studies have shown the important role microbial communities play in the male reproductive tract, indicating differences in the semen microbial composition between fertile and infertile males. Most of these studies were made on human beings but little is known regarding domestic animals. Seminal bacteria studies made in stallions mostly focus on pathogenic bacteria and on their impact on reproductive technology. However, little is known about stallion commensal seminal microflora. That ultimately hinders our capacity to associate specific bacteria to conditions or seminal quality. Therefore, the aim of this study was to characterize the seminal microbial composition of 12 healthy, fertile stallion using next-generation sequencing. Hypervariable region V3 was chosen for bacterial identification. A total of nine phyla was detected. The most abundant ones were Bacteroidetes (46.50%), Firmicutes (29.92%) and Actinobacteria (13.58%). At family level, we found 69 bacterial families, but only nine are common in all samples. Porphyromonadaceae (33.18%), Peptoniphilaceae (14.09%), Corynebacteriaceae (11.32%) and Prevotellaceae (9.05%) were the most representative ones, while the Firmicutes phylum displayed the highest number of families (23, a third of the total). Samples showed high inter-subject variability. Findings previously described in other species notably differ from our findings. Families found in human such as Lactobacillaceae, Staphylococcaceae and Streptococcaceae only represented a 0.00%, 0.17% and 0.22% abundance in our samples, respectively. In conclusion, Porphyromonadaceae, Prevotellaceae, Peptoniphilaceae and Corynebacteriaceae families are highly represented in the seminal microbiome of healthy, fertile stallions. A high variation among individuals is also observed.

Biofilm-Producing Bacteria and Risk Factors (Gender and Duration of Catheterization) Characterized as Catheter-Associated Biofilm Formation

Background

A catheter-associated urinary tract infection (CA-UTI) is preceded by biofilm formation, which is related to several risk factors such as gender, age, diabetic status, duration of catheterization, bacteriuria before catheterization, virulence gene factor, and antibiotic usage.

Aims

This study aims to identify the microbial composition of catheter samples, including its corresponding comparison with urine samples, to determine the most important risk factors of biofilm formation and characterize the virulence gene factors that correlate with biofilm formation.

Methods

A longitudinal cross-sectional study was conducted on 109 catheterized patients from September 2017 to January 2018. The risk factors were obtained from the patients' medical records. All catheter and urine samples were cultured after removal, followed by biomass quantification. Isolate identification and antimicrobial susceptibility testing were performed using the Vitex2 system. Biofilm-producing bacteria were identified by the Congo Red Agar (CRA) method. A PCR test characterized the virulence genes of dominant bacteria (E. coli). All data were collected and processed for statistical analysis.

Results

Out of 109 catheterized patients, 78% of the catheters were culture positive, which was higher than those of the urine samples (37.62%). The most common species isolated from the catheter cultures were Escherichia coli (28.1%), Candida sp. (17.8%), Klebsiella pneumoniae (15.9%), and Enterococcus faecalis (13.1%). E. coli (83.3%) and E. faecalis (78.6%) were the main isolates with a positive CRA. A statistical analysis showed that gender and duration prior to catheterization were associated with an increased risk of biofilm formation (p < 0.05).

Conclusion

E. coli and E. faecalis were the most common biofilm-producing bacteria isolated from the urinary catheter. Gender and duration are two risk factors associated with biofilm formation, therefore determining the risk of CAUTI. The presence of PapC as a virulence gene encoding pili correlates with the biofilm formation. Biofilm-producing bacteria, female gender, duration of catheterization (more than five days), and PapC gene presence have strong correlation with the biofilm formation. To prevent CAUTI, patients with risk factors should be monitored by urinalysis tests to detect earlier the risk of biofilm formation.

Flujo vaginal y semen: La microbiota de las relaciones sexuales

Durante las relaciones sexuales, se da el intercambio de especies bacterianas entre las parejas, siendo las relaciones sexuales un factor crucial en la modificación de la microbiota genital. En el presente artículo de reflexión, se analizó el efecto de las relaciones sexuales sobre el intercambio de la microbiota vaginal y seminal. Las parejas que sostienen relaciones sexuales sin protección comparten especies bacterianas que podrían influir negativamente o positivamente sobre los parámetros seminales, como los Lactobacillus con potencial probiótico para el mantenimiento de la calidad del semen.

Profile of sexually transmitted infections causing urethritis and a related inflammatory reaction in urine among heterosexual males: A flow-cytometry study

BACKGROUND

Information about the use of flow cytometry in the diagnosis of male urethritis is scarce. The current study aims to evaluate the performance of flow cytometry on first-voided urine in males with infectious urethritis (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis).

METHODS

Male patients of the Andrology Centre (Tartu University Hospital, Estonia) were recruited during the period March 2015 -January 2018. Cases included 306 patients with infectious urethritis caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and/or Trichomonas vaginalis. The control group consisted of 192 patients without uro-genital complaints, negative tests for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis from first-voided urine and no inflammation in first-voided urine, mid-stream urine and urine after prostate massage. C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis were detected from first-voided urine using polymerase chain reaction (PCR) method. First-voided urine was analysed using urine particle analyzer Sysmex UF-500i.

RESULTS

The most prevalent infection was chlamydia (64.1%), followed by Mycoplasma genitalium (20.9%), gonorrhoea (7.8%) and trichomoniasis (1.6%). Gonorrhoea caused the highest flow-cytometric leucocyte/bacteria count, followed by chlamydia and Mycoplasma genitalium. Trichomonas vaginalis showed nearly absent inflammation in first-voided urine. Using an empiric flow-cytometry diagnostic threshold for urethritis in first-voided urine (leucocytes ≥ 15/μl and bacteria ≥ 20/μl) the total calculated sensitivity was over 90%. However, when applying such criteria for deciding whether to perform first-voided urine PCR for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis or not, we could miss 23 cases with infectious urethritis that makes up 7,5% of all proven cases.

CONCLUSIONS

Flow cytometry of first-voided urine can be considered as a rapid and objective screening method in case of suspected male infectious urethritis.

The genital microbiome and its potential for detecting sexual assault

Since its inception, the Human Microbiome Project (HMP) has provided key discoveries that can be applied to forensics, in addition to those of obvious medical value. Whether for postmortem interval estimation, geolocation, or human identification, there are many applications of the microbiome as an investigative lead for forensic casework. The human skin microbiome has shown great potential for use in studies of transfer and human identification, however there has been little focus on the genital microbiome, in particular penile skin which differs from other body sites. Our preliminary data on both the penile and vaginal microbiome demonstrates potential value in cases of sexual assault. In this study we describe genital microbial signatures based on the analysis of five male and five female genital samples and compare these results to those from longitudinal studies. Selected taxa, e.g., Gardnerella, Lactobacilli, Finegoldia, Peptoniphilus, and Anaerococci, are shown to be candidate constituents of the genital microbiome that merit investigation for use in sexual assault casework.

Genomic Sequencing Reveals the Diversity of Seminal Bacteria and Relationships to Reproductive Potential in Boar Sperm

A number of emerging studies suggest that pathogenic microorganisms in semen may cause a decline in the reproductive potential of spermatozoa, and the bacterial diversity and profile of ejaculated boar semen in different seasons are currently unknown. To explore the bacterial composition and changes in ejaculated boar semen from winter and summer, and the underlying mechanism of decline in sperm quality and fertility capacity in summer, 120 ejaculated semen samples were examined for bacterial communities using genomic sequencing technology, and the associations between microbial composition and sperm reproductive potential were investigated. The results showed that Proteobacteria (57.53%), Firmicutes (31.17%), Bacteroidetes (4.24%), and Actinobacteria (3.41%) are the dominant phyla in the ejaculated semen, and the dominant genera were Pseudomonas (34.41%) and Lactobacillus (19.93%), which belong to the phyla of Proteobacteria and Firmicutes, respectively. Interestingly, the higher diversity of bacteria in ejaculated semen of winter differs from that of summer semen, potentially due to seasonal changes related to changes in semen quality and sperm fertilizing capacity. Furthermore, the highly abundant Lactobacillus in winter samples were positively associated with sperm quality and reproductive performance obtained from sows inseminated with such semen samples, while in contrast, the highly abundant Pseudomonas in summer samples was negatively associated with sperm quality and reproductive potential. Additionally, our results strongly indicated that Lactobacillus is not only a potential probiotic for semen quality and fertility potential but also beneficial for restraining the negative influence of Pseudomonas. Overall, our findings significantly contribute to the current understanding of the phenotypes and etiology of male "summer infertility," and may represent a frontier in male reproductive disorders and possible early prevention against pathogenic bacteria.

The Seminal Microbiome and Male Factor Infertility

Purpose of Review

Focusing on studies published within the last decade, we review the literature on the seminal microbiome and male factor infertility. We highlight potential mechanisms by which microbes may impact fertility and underscore key limitations and clinical implications of these studies.

Recent Findings

The seminal microbiome encompasses a metabolically and phylogenetically diverse group of microorganisms. Lactobacillus was consistently associated with normal semen analysis parameters and fertility; Anaerococcus was negatively associated with semen quality. These microbes may participate in a complex cross-talk with the host immune system, thereby modulating local and perhaps systemic inflammatory responses, impacting semen quality.

Summary

Research investigating the intersection between the seminal microbiome and male fertility is still in its infancy. Recent investigations have been exclusively cross-sectional, correlational studies, limiting the clinical applicability of published research. Prospective studies with more sophisticated methodologies are necessary.

Human microbiome and prostate cancer development: current insights into the prevention and treatment

The huge communities of microorganisms that symbiotically colonize humans are recognized as significant players in health and disease. The human microbiome may influence prostate cancer development. To date, several studies have focused on the effect of prostate infections as well as the composition of the human microbiome in relation to prostate cancer risk. Current studies suggest that the microbiota of men with prostate cancer significantly differs from that of healthy men, demonstrating that certain bacteria could be associated with cancer development as well as altered responses to treatment. In healthy individuals, the microbiome plays a crucial role in the maintenance of homeostasis of body metabolism. Dysbiosis may contribute to the emergence of health problems, including malignancy through affecting systemic immune responses and creating systemic inflammation, and changing serum hormone levels. In this review, we discuss recent data about how the microbes colonizing different parts of the human body including urinary tract, gastrointestinal tract, oral cavity, and skin might affect the risk of developing prostate cancer. Furthermore, we discuss strategies to target the microbiome for risk assessment, prevention, and treatment of prostate cancer.

What human sperm RNA-Seq tells us about the microbiome

PURPOSE

The study was designed to assess the capacity of human sperm RNA-seq data to gauge the diversity of the associated microbiome within the ejaculate.

METHODS

Semen samples were collected, and semen parameters evaluated at time of collection. Sperm RNA was isolated and subjected to RNA-seq. Microbial composition was determined by aligning sequencing reads not mapped to the human genome to the NCBI RefSeq bacterial, viral and archaeal genomes following RNA-Seq. Analysis of microbial assignments utilized phyloseq and vegan.

RESULTS

Microbial composition within each sample was characterized as a function of microbial associated RNAs. Bacteria known to be associated with the male reproductive tract were present at similar levels in all samples representing 11 genera from four phyla with one exception, an outlier. Shannon diversity index (p < 0.001) and beta diversity (unweighted UniFrac distances, p = 9.99e-4; beta dispersion, p = 0.006) indicated the outlier was significantly different from all other samples. The outlier sample exhibited a dramatic increase in Streptococcus. Multiple testing indicated two operational taxonomic units, S. agalactiae and S. dysgalactiae (p = 0.009), were present.

CONCLUSION

These results provide a first look at the microbiome as a component of human sperm RNA sequencing that has sufficient sensitivity to identify contamination or potential pathogenic bacterial colonization at least among the known contributors.

The seminal microbiome in health and disease

Owing to the fact that there are more microbial than human cells in our body and that humans contain more microbial than human genes, the microbiome has huge potential to influence human physiology, both in health and in disease. The use of next-generation sequencing technologies has helped to elucidate functional, quantitative and mechanistic aspects of the complex microorganism-host interactions that underlie human physiology and pathophysiology. The microbiome of semen is a field of increasing scientific interest, although this microbial niche is currently understudied compared with other areas of microbiome research. However, emerging evidence is beginning to indicate that the seminal microbiome has important implications for the reproductive health of men, the health of the couple and even the health of offspring, owing to transfer of microorganisms to the partner and offspring. As this field expands, further carefully designed and well-powered studies are required to unravel the true nature and role of the seminal microbiome.

Sperm Microbiota and Its Impact on Semen Parameters

Compared to its female counterpart, the microbiota of the male genital tract has not been studied extensively. With this study, we aimed to evaluate the bacterial composition of seminal fluid and its impact on sperm parameters. We hypothesized that a dysbiotic microbiota composition may have an influence on sperm quality. Semen samples of 26 men with normal spermiogram and 68 men with at least one abnormal spermiogram parameter were included in the study. Samples were stratified based on total sperm count, spermatozoa concentration, progressive motility, total motility and spermatozoa morphology. Microbiota profiling was performed using 16S rRNA gene amplicons sequencing and total bacterial load was determined using a panbacterial quantitative PCR. Semen samples broadly clustered into three microbiota profiles: Prevotella-enriched, Lactobacillus-enriched, and polymicrobial. Prevotella-enriched samples had the highest bacterial load (p < 0.05). Network analysis identified three main co-occurrence modules, among which two contained bacteria commonly found in the vaginal flora. Genera from the same module displayed similar oxygen requirements, arguing for the presence of different ecological niches for bacteria that colonize semen through the passage. Contrary to our hypothesis, shifts in overall microbiota composition (beta-diversity) did not correlate with spermiogram parameters. Similarly, we did not find any difference in microbial richness or diversity (alpha-diversity). Differential abundance testing, however, revealed three specific genera that were significantly enriched or depleted in some of the sperm quality groups (p < 0.05). Prevotella relative abundance was increased in samples with defective sperm motility while Staphylococcus was increased in the corresponding control group. In addition, we observed an increased relative abundance of Lactobacillus in samples with normal sperm morphology. Our study indicates that overall bacterial content of sperm might not play a major role in male infertility. Although no major shifts in microbiota composition or diversity were found, the differential abundance of specific bacterial genera in the sperm suggests that a small subset of microbes might impact the spermatozoal physiology during sperm transition, more specifically motility and morphology. Further studies are required to challenge this finding and develop potential strategies to induce the formation of a healthy seminal microbiota.

β-Defensins: Farming the Microbiome for Homeostasis and Health

Diverse commensal populations are now regarded as key to physiological homeostasis and protection against disease. Although bacteria are the most abundant component of microbiomes, and the most intensively studied, the microbiome also consists of viral, fungal, archael, and protozoan communities, about which comparatively little is known. Host-defense peptides (HDPs), originally described as antimicrobial, now have renewed significance as curators of the pervasive microbial loads required to maintain homeostasis and manage microbiome diversity. Harnessing HDP biology to transition away from non-selective, antibiotic-mediated treatments for clearance of microbes is a new paradigm, particularly in veterinary medicine. One family of evolutionarily conserved HDPs, β-defensins which are produced in diverse combinations by epithelial and immune cell populations, are multifunctional cationic peptides which manage the cross-talk between host and microbes and maintain a healthy yet dynamic equilibrium across mucosal systems. They are therefore key gatekeepers to the oral, respiratory, reproductive and enteric tissues, preventing pathogen-associated inflammation and disease and maintaining physiological normality. Expansions in the number of genes encoding these natural antibiotics have been described in the genomes of some species, the functional significance of which has only recently being appreciated. β-defensin expression has been documented pre-birth and disruptions in their regulation may play a role in maladaptive neonatal immune programming, thereby contributing to subsequent disease susceptibility. Here we review recent evidence supporting a critical role for β-defensins as farmers of the pervasive and complex prokaryotic ecosystems that occupy all body surfaces and cavities. We also share some new perspectives on the role of β-defensins as sensors of homeostasis and the immune vanguard particularly at sites of immunological privilege where inflammation is attenuated.

Reproductive Microbiomes in Wild Animal Species: A New Dimension in Conservation Biology

Communities of microbes have coevolved in animal organisms and are found in almost every part of the body. Compositions of those communities (microbiota) as well as their genomes and genes (microbiomes) are critical for functional regulations of the body organ systems-the digestive or 'gut' microbiome being the most described so far. Based on extensive research in humans, microbiomes in the reproductive tract may play a role in reproductive functions and pregnancy. However, in wild animal species, those microbiomes have been poorly studied, and as a result, little is known about their involvement in fertility or parental/offspring health. This emerging research area is highly relevant to conservation biology from captive breeding management to successful reintroduction or maintenance of wild populations. The objective of this chapter is to review current knowledge about reproductive microbiomes in healthy wild animal species. While recognizing the current technical limits of microbial identification in all animal species, we also explore the link between microbial communities (within female or male reproductive systems) and fertility, from conception to birth outcome. In addition, it is critical to understanding how reproductive microbiomes are affected by environmental factors (including captivity, contact with other individuals, or changes in the ecosystem) to optimize conservation efforts. Thus, reproductive microbiomes represent a novel dimension in conservation biology that will likely gain importance in the future.

Impact of asymptomatic genital tract infections on in vitro Fertilization (IVF) outcome

Background

Infertility is estimated to affect approximately 9–30% of reproductive-aged couples. Several conditions involving one or both partners may contribute to infertility. The aim of this study is to evaluate the role of asymptomatic genital tract infections in the outcome of In Vitro Fertilization (IVF) in couples with infertility.

Methods

A total of 285 infertile couples were enrolled in the study. Vaginal/endocervical swabs and semen samples were collected and subjected to microbiological analysis. Spermiograms were carried out on semen specimens, and lactobacilli were quantified in vaginal swabs. Data were associated with IVF results and analysed by using non parametric tests and multivariate analysis.

Results

Microbiological analysis showed that 46.3% of couples presented with an asymptomatic genital tract infection. Spermiogram results showed a significantly diminished motility of sperm cells in samples positive to microbiological testing compared to negative specimens. Enterococcus faecalis was the most prevalent species (11.6%) in positive semen samples and was found to negatively affect both sperm morphology (p = 0.026) and motility (p = 0.003). Analysis of genital swabs from females showed that the presence of E. faecalis (p<0.0001), Escherichia coli (p = 0.0123), Streptococcus agalactiae (p<0.0001), and Gardnerella vaginalis (p = 0.0003) was significantly associated to reduced levels of vaginal lactobacilli. Association of microbiological data with IVF outcome showed that 85.7% of IVF+ couples was microbiologically negative, while IVF was successful in just 7.5% of couples infected with E. faecalis and/or U. urealyticum and/or M. hominis (p = 0.02).

Conclusions

The results show the negative impact of E. faecalis on sperm quality and the association of definite bacterial pathogens with reduced levels of vaginal lactobacilli. The presence of E. faecalis and/or U. urealyticum and/or M. hominis in genital samples of infertile couples is predictive for a negative outcome of IVF.

Male Partners of Infertile Couples With Seminal Positivity for Markers of Bacterial Vaginosis Have Impaired Fertility

To access the possibility that key markers of bacterial vaginosis (KM-BV) could affect seminal parameters and thus fertility a prospective cohort study was designed (a) to develop rapid and sensitive multiplex polymerase chain reaction (M-PCR) assays to screen 13 key markers of bacterial vaginosis (KM-BV) in semen specimens, (b) to determine the prevalence of KM-BV in semen from randomized male partners of couples seeking fertility evaluation. A total of 229 semen samples were included in the study from males who visited the Sperm Analysis Section of Brazil between October 2015 and March 2016. Eligible men were 18 years or older and had a semen analysis due fertility evaluation (after failing to conceive with their partner after 1 year of unprotected intercourse). Basic seminal parameters were analyzed, and KM-BV was detected by M-PCR assays. M-PCR assays clearly distinguished 13 KM-BV in 146 semen samples (63.8%), mainly Gardnerella vaginalis (50.7%). Some important associations occurred between the presence of KM-BV in semen and changes in seminal parameters. KM-BV is commonly present in the semen of males seeking fertility evaluation and could potentially play significant roles in male subfertility and/or infertility.

Impact of sexual debut on culturable human seminal microbiota

Micro-organisms are tightly integrated into host-microbiota ecosystem. Microbiota of human semen has been studied so far mostly in case of infertility or prostatitis. We aimed to reveal possible impact of sexual debut on seminal microbiota in healthy young men. The study group included 68 young healthy men, of them 12 men without sexual experience, 11 men with single lifetime sexual partner and 45 men with multiple lifetime sexual partners. Basic semen parameters were similar for all subgroups, and no correlation between sexual experience and WBC counts in semen was found. A man could harbour one to nine different bacteria in his semen; the total concentration of bacteria ranged from 2.3 to 7.3 log₁₀ CFU/mL of semen. Lower total bacterial concentration and lower bacterial diversity was observed in men without sexual experience than in sexually experienced men (p < 0.05), with significant positive correlation between these two parameters (r = 0.54; p < 0.0001). In conclusion, the sexual debut is associated with the enrichment of seminal microbiota but not with the influx of WBC or changes in basic seminal parameters.

The First Microbial Colonizers of the Human Gut: Composition, Activities, and Health Implications of the Infant Gut Microbiota

The human gut microbiota is engaged in multiple interactions affecting host health during the host's entire life span. Microbes colonize the neonatal gut immediately following birth. The establishment and interactive development of this early gut microbiota are believed to be (at least partially) driven and modulated by specific compounds present in human milk. It has been shown that certain genomes of infant gut commensals, in particular those of bifidobacterial species, are genetically adapted to utilize specific glycans of this human secretory fluid, thus representing a very intriguing example of host-microbe coevolution, where both partners are believed to benefit. In recent years, various metagenomic studies have tried to dissect the composition and functionality of the infant gut microbiome and to explore the distribution across the different ecological niches of the infant gut biogeography of the corresponding microbial consortia, including those corresponding to bacteria and viruses, in healthy and ill subjects. Such analyses have linked certain features of the microbiota/microbiome, such as reduced diversity or aberrant composition, to intestinal illnesses in infants or disease states that are manifested at later stages of life, including asthma, inflammatory bowel disease, and metabolic disorders. Thus, a growing number of studies have reported on how the early human gut microbiota composition/development may affect risk factors related to adult health conditions. This concept has fueled the development of strategies to shape the infant microbiota composition based on various functional food products. In this review, we describe the infant microbiota, the mechanisms that drive its establishment and composition, and how microbial consortia may be molded by natural or artificial interventions. Finally, we discuss the relevance of key microbial players of the infant gut microbiota, in particular bifidobacteria, with respect to their role in health and disease.

The Microbiome of the Prostate Tumor Microenvironment

BACKGROUND

The advent of molecular-based methods of identification and characterization of complex microbial populations has led to a new era of microbial discovery. A detailed and comprehensive analysis of the microbial ecosystem of the pathologic and healthy prostate tissues has not been yet reported.

OBJECTIVES

To characterize the microbiome possibly associated to the pathologic prostate microenvironment.

DESIGN, SETTING, AND PARTICIPANTS

The microbiome profile of tumor, peri-tumor, and nontumor tissues was assessed on 16 radical prostatectomy-specimens.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Microbiome analysis was assessed by massive ultradeep pyrosequencing. Bacteria load was expressed as a percentage of the total number of bacteria. The statistical significance of differences among specimen-groups was tested with Friedman's test (Dunn posthoc test) and Wilcoxon rank-sum test.

RESULTS AND LIMITATIONS

Three phyla, six classes, nine orders, 14 families, and 11 genera were above the set threshold value of 1%, respectively. Significant differences in specific microbial populations among tumor/peri-tumor and nontumor prostate specimens were observed at certain taxonomic levels. Among genera, Propionibacterium spp. were the most abundant. Staphylococcus spp. were more represented in the tumor/peri-tumor tissues (p<0.05). The restricted number of specimens represents a potential limitation.

CONCLUSIONS

The prostate contains a plethora of bacteria, which set themselves within the gland with a distribution dependent on the nature of the tissue, thus suggesting a possible pathophysiological correlation between the composition of the local microbial niche and the presence of the tumor itself. Future studies will help to clarify the role of these specific bacteria and their potential to be exploited as new biomarkers.

PATIENT SUMMARY

The pathological prostate is populated by specific microbial populations, whose distribution varies according to the nature of the tissue. This finding opens interesting perspectives for the identification of novel therapeutic approaches and biomarkers.

Seminal microbiome in men with and without prostatitis

OBJECTIVES

To profile the seminal microbiome applying next generation sequencing.

METHODS

Semen samples of 67 men were involved in the study (21 men with and 46 men without prostatitis). Seminal microbiomes were profiled applying the method that uses combinatorial sequence tags attached to polymerase chain reaction primers that amplify the ribosomal ribonucleic acid V6 region. Amplified polymerase chain reaction products were sequenced using an Illumina paired-end protocol on HiSeq2000 platform.

RESULTS

The most abundant phylum in semen was Firmicutes, comprising nearly half of the sequences found (median 41.7%, quartiles 28.5-47.2%) followed by Bacteroidetes, Proteobacteria and Actinobacteria. The counts of lactobacilli were higher in healthy men than prostatitis patients (27% [20.2-34.6%] vs 20.2% [4.9-25.0%]; P = 0.05), especially for Lactobacillus iners. Proteobacteria comprised higher proportions in prostatitis patients than healthy men. The species richness was higher in prostatitis patients than healthy men (inverted Simpson index 13.5 ± 5.8 vs 10.3 ± 4.0).

CONCLUSIONS

The semen of chronic prostatitis patients contains fewer health-supporting lactobacilli, and has higher species diversity than that of healthy men. Firmicutes (especially lactobacilli), Bacteroidetes, Proteobacteria and Actinobacteria comprise the highest proportion of seminal microbiome.

Antibiotic treatment for the sexual partners of women with bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) is an infection that has a prevalence between 10% to 50% worlwide. BV results in an imbalance of the normal vaginal flora. Microorganisms associated with BV have been isolated from the normal flora of the male genital tract, and their presence could be related to the recurrence of BV after antibiotic treatment. Therefore, the treatment of sexual partners could decrease the recurrence of infection and possibly the burden of the disease.

OBJECTIVES

To assess the effectiveness in women and the safety in men of concurrent antibiotic treatment for the sexual partners of women treated for BV.

SEARCH METHODS

We searched the Cochrane Sexually Transmitted Infections Group Specialized Register (23 July 2016), CENTRAL (1991 to 23 July 2016), MEDLINE (1946 to 23 July 2016), Embase (1974 to 23 July 2016), LILACS (1982 to 23 July 2016), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (23 July 2016), ClinicalTrials.gov (23 July 2016) and the Web of Science™ (2001 to 23 July 2016). We also handsearched conference proceedings, contacted trial authors and reviewed the reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared the concurrent use of any antibiotic treatment with placebo, no intervention or any other intervention by the sexual partners of women treated for BV.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion, extracted data and assessed the risk of bias in the included studies. We resolved any disagreements through consensus. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

Seven RCTs (1026 participants) met our inclusion criteria, and pharmaceutical industry funded four of these trials. Five trials (854 patients) compared any antibiotic treatment of sexual partners with placebo. Based on high quality evidence, antibiotic treatment does not increase the rate of clinical or symptomatic improvement in women during the first week (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.96 to 1.03; 712 participants, four studies; RR 1.06, 95% CI 1.00 to 1.12; 577 patients, three studies, respectively), between the first and fourth week (RR 1.02, 95% CI 0.94 to 1.11; 590 participants, three studies; RR 0.93, 95% CI 0.84 to 1.03; 444 participants, two studies; respectively) or after the fourth week (RR 0.98, 95% CI 0.90 to 1.07; 572 participants, four studies; RR 1.03, 95% CI 0.90 to 1.17; 296 participants, two studies; respectively). Antibiotic treatment does not led to a lower recurrence during the first and fourth week (RR 1.28, 95% CI 0.68 to 2.43; 218 participants, one study; low quality evidence) or after the fourth week of treatment (RR 1.00, 95% CI 0.67 to 1.52; 372 participants, three studies; low quality evidence) in women, but increases the frequency of adverse events (most frequently gastrointestinal symptoms) reported by sexual partners (RR 2.55, 95% CI 1.55 to 4.18; 477 participants, three studies; low quality evidence). Two trials (172 participants) compared any antibiotic treatment for sexual partners with no intervention. When we compared it with no intervention, the effects of antibiotic treatment on recurrence rate after the fourth week (RR 1.71, 95% CI 0.65 to 4.55; 51 participants, one study), clinical improvement between the first and fourth week (RR 0.93, 95% CI 0.70 to 1.25; 152 participants, two studies) and symptomatic improvement after the fourth week (RR 0.66, 95% CI 0.39 to 1.11; 70 participants, one study) were imprecise and there were no differences between groups. We downgraded the quality of the evidence to low or very low.

AUTHORS' CONCLUSIONS

High quality evidence shows that antibiotic treatment for sexual partners of women with BV, compared with placebo, does not increase the rate of clinical or symptomatic improvement during the first, between the first and fourth or after the fourth week into the women. Low quality evidence suggests that antibiotic treatment does not led to a lower recurrence rate during the first and fourth or after the fourth week of treatment into the women, but increases the frequency of adverse events reported by sexual partners. Finally, compared with no intervention, antibiotic treatment does not decrease the recurrence rate after the fourth week and does not increase the frequency of clinical or symptomatic improvement between the first and fourth or after the fourth week into the women, respectively.

Management of non-gonococcal urethritis

Non-gonococcal urethritis (NGU), or inflammation of the urethra, is the most common treatable sexually transmitted syndrome in men, with approximately 20-50 % of cases being due to infection with Chlamydia trachomatis and 10-30 % Mycoplasma genitalium. Other causes are Ureaplasma urealyticum, Trichomonas vaginalis, anaerobes, Herpes simplex virus (HSV) and adenovirus. Up to half of the cases are non-specific. Urethritis is characterized by discharge, dysuria and/or urethral discomfort but may be asymptomatic. The diagnosis of urethritis is confirmed by demonstrating an excess of polymorpho-nuclear leucocytes (PMNLs) in a stained smear. An excess of mononuclear leucocytes in the smear indicates a viral etiology. In patients presenting with symptoms of urethritis, the diagnosis should be confirmed by microscopy of a stained smear, ruling out gonorrhea. Nucleid acid amplifications tests (NAAT) for Neisseria gonorrhoeae, C. trachomatis and for M. genitalium. If viral or protozoan aetiology is suspected, NAAT for HSV, adenovirus and T. vaginalis, if available. If marked symptoms and urethritis is confirmed, syndromic treatment should be given at the first appointment without waiting for the laboratory results. Treatment options are doxycycline 100 mg x 2 for one week or azithromycin 1 gram single dose or 1,5 gram distributed in five days. However, azithromycin as first line treatment without test of cure for M. genitalium and subsequent Moxifloxacin treatment of macrolide resistant strains will select and increase the macrolide resistant strains in the population. If positive for M. genitalium, test of cure samples should be collected no earlier than three weeks after start of treatment. If positive in test of cure, moxifloxacin 400 mg 7-14 days is indicated. Current partner(s) should be tested and treated with the same regimen. They should abstain from intercourse until both have completed treatment. Persistent or recurrent NGU must be confirmed with microscopy. Reinfection and compliance must be considered. Evidence for the following recommendations is limited, and is based on clinical experience and guidelines. If doxycycline was given as first therapy, azithromycin five days plus metronidazole 4-500 mg twice daily for 5-7 days should be given. If azithromycin was prescribed as first therapy, doxycycline 100 mg x 2 for one week plus metronidazole, or moxifloxacin 400 mg orally once daily for 7-14 days should be given.

Individualized medicine and the microbiome in reproductive tract

Humans have evolved along with the millions of microorganisms that populate their bodies. These microbes (10(14)) outnumber human cells by 10 to 1 and account for 3 × 10(6) genes, more than ten times the 25,000 human genes. This microbial metagenome acts as our "other genome" and like our own genes, is unique to the individual. Recent international efforts such as the Human Microbiome Project (HMP) and the MetaHIT Project have helped catalog these microbial genomes using culture-independent, high-throughput, next-generation sequencing. This manuscript will describe recent efforts to define microbial diversity in the female reproductive tract because of the impact that microbial function has on reproductive efficiency. In this review, we will discuss current evidence that microbial communities are critical for maintaining reproductive health and how perturbations of microbial community structures can impact reproductive health from the aspect of infection, reproductive cyclicity, pregnancy, and disease states. Investigations of the human microbiome are propelling interventional strategies from treating medical populations to treating individual patients. In particular, we highlight how understanding and defining microbial community structures in different disease and physiological states have lead to the discovery of biomarkers and, more importantly, the development and implementation of microbial intervention strategies (probiotics) into modern day medicine. Finally this review will conclude with a literature summary of the effectiveness of microbial intervention strategies that have been implemented in animal and human models of disease and the potential for integrating these microbial intervention strategies into standard clinical practice.

Amino acid metabolism in intestinal bacteria and its potential implications for mammalian reproduction

Reproduction is vital for producing offspring and preserving genetic resources. However, incidences of many reproductive disorders (e.g. miscarriage, intrauterine growth restriction, premature delivery and lower sperm quality) have either increased dramatically or remained at high rates over the last decades. Mounting evidence shows a strong correlation between enteral protein nutrition and reproduction. Besides serving as major nutrients in the diet, amino acids (AA) are signaling molecules in the regulation of diverse physiological processes, ranging from spermatogenesis to oocyte fertilization and to embryo implantation. Notably, the numbers of bacteria in the intestine exceed the numbers of host cells by 10 times. Microbes in the small-intestinal lumen actively metabolize large amounts of dietary AA and, therefore, affect the entry of AA into the portal circulation for whole-body utilization. Changes in the composition and abundance of AA-metabolizing bacteria in the gut during pregnancy, as well as their translocation to the uterus, may alter uterine function and epigenetic modifications of maternal physiology and metabolism, which are crucial for pregnancy recognition and fetal development. Thus, the presence of the maternal gut microbiota and AA metabolites in the intrauterine environments (e.g. endometrium and placenta) and breast milk is likely a unique signature for the programming of the whole-body microbiome and metabolism in both the fetus and infant. Dietary intervention with functional AA, probiotics and prebiotics to alter the abundance and activity of intestinal bacteria may ameliorate or prevent the development of metabolic syndrome, while improving reproductive performance in both males and females as well as their offspring.

Bacterial communities in semen from men of infertile couples: metagenomic sequencing reveals relationships of seminal microbiota to semen quality

Some previous studies have identified bacteria in semen as being a potential factor in male infertility. However, only few types of bacteria were taken into consideration while using PCR-based or culturing methods. Here we present an analysis approach using next-generation sequencing technology and bioinformatics analysis to investigate the associations between bacterial communities and semen quality. Ninety-six semen samples collected were examined for bacterial communities, measuring seven clinical criteria for semen quality (semen volume, sperm concentration, motility, Kruger's strict morphology, antisperm antibody (IgA), Atypical, and leukocytes). Computer-assisted semen analysis (CASA) was also performed. Results showed that the most abundant genera among all samples were Lactobacillus (19.9%), Pseudomonas (9.85%), Prevotella (8.51%) and Gardnerella (4.21%). The proportion of Lactobacillus and Gardnerella was significantly higher in the normal samples, while that of Prevotella was significantly higher in the low quality samples. Unsupervised clustering analysis demonstrated that the seminal bacterial communities were clustered into three main groups: Lactobacillus, Pseudomonas, and Prevotella predominant group. Remarkably, most normal samples (80.6%) were clustered in Lactobacillus predominant group. The analysis results showed seminal bacteria community types were highly associated with semen health. Lactobacillus might not only be a potential probiotic for semen quality maintenance, but also might be helpful in countering the negative influence of Prevotella and Pseudomonas. In this study, we investigated whole seminal bacterial communities and provided the most comprehensive analysis of the association between bacterial community and semen quality. The study significantly contributes to the current understanding of the etiology of male fertility.