The bacterial flora of the genitourinary tract in healthy fertile men

Leukocytospermia and/or Bacteriospermia: Impact on Male Infertility

Infertility is a globally underestimated public health concern affecting almost 190 million people, i.e., about 17.5% of people during their lifetime, while the prevalence of male factor infertility is about 7%. Among numerous other causes, the prevalence of male genital tract infections reportedly ranges between 10% and 35%. Leukocytospermia is found in 30% of infertile men and up to 20% in fertile men. Bacterial infections cause an inflammatory response attracting leukocytes, which produce reactive oxygen species (ROS) and release cytokines, both of which can cause damage to sperm, rendering them dysfunctional. Although leukocytospermia and bacteriospermia are both clinical conditions that can negatively affect male fertility, there is still debate about their impact on assisted reproduction outcomes and management. According to World Health Organization (WHO) guidelines, leukocytes should be determined by means of the Endtz test or with monoclonal antibodies against CD15, CD68 or CD22. The cut-off value proposed by the WHO is 1 × 106 peroxidase-positive cells/mL. For bacteria, Gram staining and semen culture are regarded as the "gold standard", while modern techniques such as PCR and next-generation sequencing (NGS) are allowing clinicians to detect a wider range of pathogens. Whereas the WHO manual does not specify a specific value as a cut-off for bacterial contamination, several studies consider semen samples with more than 103 colony-forming units (cfu)/mL as bacteriospermic. The pathogenic mechanisms leading to sperm dysfunction include direct interaction of bacteria with the male germ cells, bacterial release of spermatotoxic substances, induction of pro-inflammatory cytokines and ROS, all of which lead to oxidative stress. Clinically, bacterial infections, including "silent" infections, are treatable, with antibiotics being the treatment of choice. Yet, non-steroidal antiphlogistics or antioxidants should also be considered to alleviate inflammatory lesions and improve semen quality. In an assisted reproduction set up, sperm separation techniques significantly reduce the bacterial load in the semen. Nonetheless, contamination of the semen sample with skin commensals should be prevented by applying relevant hygiene techniques. In patients where leukocytospermia is detected, the causes (e.g. infection, inflammation, varicocele, smoking, etc.) of the leukocyte infiltration have to be identified and addressed with antibiotics, anti-inflammatories or antioxidants in cases where high oxidative stress levels are detected. However, no specific strategy is available for the management of leukocytospermia. Therefore, the relationship between bacteriospermia and leukocytospermia as well as their specific impact on functional sperm parameters and reproductive outcome variables such as fertilization or clinical pregnancy must be further investigated. The aim of this narrative review is to provide an update on the current knowledge on leukocytospermia and bacteriospermia and their impact on male fertility.

[Infections and male infertility]

BACKGROUND

The role of urogenital infections in male infertility has long been the subject of debate.

METHODS

A bibliographic search limited to English-language literature on human subjects published before 5/2023 resulted in the selection of 189 articles.

RESULTS

Male infertility is often of multifactorial aetiology, and to optimise the prognosis it is important to manage all the factors that can be corrected, including infectious causes, which represent one of the most frequent aetiologies. The infectious agents involved in urogenital infections are most often bacterial or viral, and more rarely parasitic. They can infect the seminal tract, male accessory glands and/or testicles, and usually result in inflammation and increased oxidative stress. These infections reduce male fertility, in particular by altering spermogram parameters and increasing sperm DNA fragmentation. For these reasons, the search for a urogenital infection should be systematic, involving a careful history and clinical examination, ultrasound and systematic bacteriological tests guided by clinical findings. Aetiological treatment may be proposed depending on the picture and the germ involved.

CONCLUSION

This review should help the urologist to establish an accurate diagnosis of the form and extent of the infection, and enable him to define an appropriate therapeutic strategy, tailored to the patient, in order to obtain the best chances of improving male fertility.

Male infertility and the human microbiome

The historical belief in urology was that the genitourinary system should be sterile in a normal, healthy, asymptomatic adult. This idea was perpetuated for decades until research revealed a diverse microbiota existing in human anatomical niches that contributed to both human health and disease processes. In recent years, the search for an etiology and modifiable risk factors in infertility has turned to the human microbiome as well. Changes in the human gut microbiome have been associated with changes in systemic sex hormones and spermatogenesis. Certain microbial species are associated with higher levels of oxidative stress, which may contribute to an environment higher in oxidative reactive potential. Studies have demonstrated a link between increased oxidative reactive potential and abnormal semen parameters in infertile men. It has also been hypothesized that antioxidant probiotics may be able to correct an imbalance in the oxidative environment and improve male fertility, with promising results in small studies. Further, the sexual partner's microbiome may play a role as well; studies have demonstrated an overlap in the genitourinary microbiomes in sexually active couples that become more similar after intercourse. While the potential applications of the microbiome to male fertility is exciting, there is a need for larger studies with uniform microbial sequencing procedures to further expand this topic.

Relevance of Leukocytospermia and Semen Culture and Its True Place in Diagnosing and Treating Male Infertility

The current WHO 2010 manual for human semen analysis defines leukocytospermia as the presence of peroxidase-positive leukocytes at a concentration >1×106/mL of semen. Granular leukocytes when activated are capable of generating high levels of reactive oxygen species in semen resulting in oxidative stress. Oxidative stress has been correlated with poor sperm quality, increased level of sperm DNA fragmentation and low fertility potential. The presence of leukocytes and pathogens in the semen may be a sign of infection and/or localized inflammatory response in the male genital tract and the accessory glands. Common uro-pathogens including Chlamydia trachomatis, Ureaplasma urealyticum, Neisseria gonorrhoeae, Mycoplasma hominis, and Escherichia coli can cause epididymitis, epididymo-orchitis, or prostatitis. The relationship between leukocytospermia and infection is unclear. Therefore, we describe the pathogens responsible for male genital tract infections and their association with leukocytospermia. The review also examines the diagnostic tests available to identify seminal leukocytes. The role of leukocytospermia in male infertility and its management is also discussed.

Core Microbiome of Slovak Holstein Friesian Breeding Bulls' Semen

Simple Summary

The aim of this study was to characterize the bacterial profile of semen collected from Holstein Friesian breeding bulls via a high-throughput sequencing approach for a 16S rRNA gene variability analysis. A total of 55 fresh semen samples of sexually mature breeding bulls were used in the study. They were gathered from Holstein Friesian breeding bulls at Slovak Biological Services in Nitra, Slovak Republic. To amplify the V4 region of the 16S rRNA bacterial gene, universal primers 515F and 806R enhanced by a 6 bp barcode identification sequence were used. The 16S rRNA high-throughput sequencing strategy was used. Two microbial clusters were identified among the analyzed samples—the first cluster was based on Actinobacteria and Firmicutes, while the second cluster contained a high prevalence of Fusobacteria.

Abstract

Bacterial contamination of semen is an important factor connected to the health status of bulls that may significantly affect semen quality for artificial insemination. Moreover, some important bovine diseases may be transmitted through semen. Up to now, only a very limited number of complex studies describing the semen microbiome of bulls have been published, as many bacteria are hard to cultivate using traditional techniques. The 16S rRNA high-throughput sequencing strategy allows for the reliable identification of bacterial profiles of bovine semen together with the detection of noncultivable bacterial species. Fresh samples from Holstein Friesian breeding bulls (n = 55) were examined for the natural variability in the present bacteria. Semen doses were selected randomly from Slovak Biological Services in Nitra, Slovak Republic. The most predominant phyla within the whole dataset were Firmicutes (31%), Proteobacteria (22%), Fusobacteria (18%), Actinobacteria (13%) and Bacteroidetes (12%). Samples of semen were divided into two separate clusters according to their microbiome compositions using a cording partition around a medoids analysis. Microbiomes of the first cluster (CL1) of samples (n = 20) were based on Actinobacteria (CL1 average = 25%; CL = 28%) and Firmicutes (CL1 = 38%; CL2 = 27%), while the second cluster (CL2; n = 35) contained samples characterized by a high prevalence of Fusobacteria (CL1 = 4%; CL2 = 26%). Some important indicator microbial groups were differentially distributed between the clusters.

Semen: A modulator of female genital tract inflammation and a vector for HIV-1 transmission

In order to establish productive infection in women, HIV must transverse the vaginal epithelium and gain access to local target cells. Genital inflammation contributes to the availability of HIV susceptible cells at the female genital mucosa and is associated with higher HIV transmission rates in women. Factors that contribute to genital inflammation may subsequently increase the risk of HIV infection in women. Semen is a highly immunomodulatory fluid containing several bioactive molecules with the potential to influence inflammation and immune activation at the female genital tract. In addition to its role as a vector for HIV transmission, semen induces profound mucosal changes to prime the female reproductive tract for conception. Still, most studies of mucosal immunity are conducted in the absence of semen or without considering its immune impact on the female genital tract. This review discusses the various mechanisms by which semen exposure may influence female genital inflammation and highlights the importance of routine screening for semen biomarkers in vaginal specimens to account for its impact on genital inflammation.

The microbiome of the infertile male

PURPOSE OF REVIEW

Contrary to historic dogma, many tissues and organs in the human body contain a resident population of bacteria, fungi, and viruses collectively known as the microbiome. The microbiome plays a role in both homeostatic symbiosis and also pathogenic dysbiosis in a wide array of diseases. Our understanding of the relationship between the microbiome and male factor infertility is in its infancy but is slowly evolving.

RECENT FINDINGS

Recent literature indicates that semen (and likely the testis) is not sterile and contains a distinct microbiome, and these changes in its composition are associated with alterations in semen quality and fertility status. Preliminary investigation indicates that manipulating the human microbiome may have implications in improving semen parameters and fertility.

SUMMARY

In this review, we describe relationships between the microbiome and the genitourinary system, discuss the prior work on the relationship among bacteriospermia, leukocytospermia and male factor infertility, and summarize the current literature utilizing 16s rRNA-based next-generation sequencing on the seminal and testicular microbiome. We explore the specific microbial taxa implicated in various aspects of spermatic dysfunction and introduce preliminary evidence for therapeutic approaches to alter the microbiome and improve fertility status.

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.

Time trends for bacterial species and resistance patterns in semen in patients undergoing evaluation for male infertility

Semen from asymptomatic men who are being evaluated as male partners in interfile couples have been reported to contain a variety of bacteria. Longitudinal studies of the variation of these bacteria over time and their resistance patterns have not been commonly reported. At our institution, residues from semen samples are routinely evaluated for bacteria, including antibiotic sensitivity profiles. We set out to profile the changes in semen bacteria and antibiotic resistance at our institution over time. A total of 72 semen isolates were examined for type of bacteria and sensitivity to a panel of antibiotics. The results were divided into two separate 5-year intervals (the first beginning in 2006, the second in 2011) and compared. The majority of bacteria were skin flora, with Streptococcus and Staphylococcus being the most prevalent. The resistance data for these two pathogens showed minimal statistically significant difference between the two time periods, although the Staphylococcus species did show a trend toward increasing resistance, suggesting that antibiotics currently used in sperm cell preparations may need to be varied.

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.

Significance of positive semen culture in relation to male infertility and the assisted reproductive technology process

There are currently no WHO guidelines on the indications for semen culture; however, semen cultures are performed in the evaluation of male infertility and the assisted reproductive technology (ART) process. The relevance and significance of positive semen cultures is widely debated in the literature, with no current consensus on the usefulness of this test in relation to male infertility. We review the pathogenic mechanisms of potentially pathogenic bacteria, general bacteria, urethral flora, and skin flora on sperm parameters. We also present, possible routes of semen contamination, measures to reduce contamination, and the clinical significance of culture contamination. First, it is critical to distinguish round cells in semen as leukocytes from immature germ cells. Second, it is critical to distinguish leukocytospermia from infected semen in order to guide management.

Androgen regulation of host defenses and response to inflammatory stimuli in the prostate gland

The prostate gland is a strictly androgen-dependent organ which is also the main target of infectious and inflammatory diseases in the male reproductive tract. Host defenses and immunity of the gland have unique features to maintain a constant balance between response and tolerance to diverse antigens. In this context, the effects of reproductive hormones on the male tract are thus complex and have just started to be defined. From the classical description of "the prostatic antibacterial factor," many host defense proteins with potent microbicidal and anti-tumoral activities have been described in the organ. Indeed, it has been proposed a central role for resident cells, that is, epithelial and smooth muscle cells, in the prostatic response against injuries. However, these cells also represent the target of the inflammatory damage, leading to the development of a Proliferative Inflammatory Atrophy-like process in the epithelium and a myofibroblastic-like reactive stroma. Available data on androgen regulation of inflammation led to a model of the complex control, in which the final effect will depend on the tissue microenvironment, the cause of inflammation, and the levels of androgens among other factors. In this paper, we review the current scientific literature about the inflammatory process in the gland, the modulation of host defense proteins, and the influence of testosterone on the resolution of prostatitis.

Intraprostatic Reflux of Urine Induces Inflammation in a Rat

BACKGROUND

We examined whether urine reflux into the prostate can induce prostatic inflammation in a rat and evaluated the effect of α1-adrenoreceptor antagonist.

METHODS

Experiment 1: Male Sprague-Dawley rats were injected with 500 µl of Evans Blue through the urethral orifice. Intravesical pressure was measured, and the prostate was excised to evaluate urine reflux. Experiment 2: Rats were injected with 500 µl urine or saline (control) from the urethral orifice. Silodosin (200 µg/kg/day) was administered to the silodosin group. We evaluated histopathology, the expression of proinflammatory cytokines and oxidative stress markers of the prostate on day 7, after assessing the prostatic microcirculation and cystometrogram.

RESULTS

Experiment 1: The histopathology showed that Evans Blue instilled through the urethral orifice entered the prostatic ducts. Intravesical pressure during Evans Blue instillation was 47.7 ± 1.6 cmH₂ O (mean ± standard error). Experiment 2: On day 7 after urine instillation through the urethral orifice, histopathology showed infiltrated inflammatory cells in the peri-glandular stroma. Inflammation-associated proteins (IL-1α, IL-1β, IL-6, and TNFα) were upregulated in the urine-instilled rats but not in the silodosin group. Erythrocyte speed on the prostatic surface, immunostaining for hypoxyprobe, and quantification of oxidative stress markers (MDA and HIF-1α) demonstrated prostatic hypoxia in the urine-instilled rats, which was ameliorated in the silodosin group. Cystometrogram revealed a shorter intercontraction interval in the urine-instilled rats, which was prolonged in the silodosin group.

CONCLUSIONS

Urine reflux into the prostatic duct induces abacterial prostatitis. Silodosin relieved prostatic inflammation and bladder overactivity by increasing microcirculation in the prostate. Prostate 77:164-172, 2017. © 2016 Wiley Periodicals, Inc.

Efficacy of two sperm preparation techniques in reducing non-specific bacterial species from human semen

CONTEXT

Artificial reproductive techniques using seminal preparations with bacteria may cause pelvic inflammatory disease and its sequalae.

AIMS

To assess efficacy of two sperm preparation techniques to clear bacteria and the effect of bacteriospermia on sperm recovery rates.

SETTINGS AND DESIGN

A descriptive cross-sectional study was carried out among males of subfertile couples.

SUBJECTS AND METHODS

Semen samples were randomly allocated into swim-up method (group S, n = 68) and density gradient method (group D, n = 50) for sperm preparation. Seminal fluid analysis and bacterial cultures were performed in each sample before and after sperm preparation.

STATISTICAL ANALYSIS

McNemar's chi-squared test and independent samples t-test in SPSS version 16.0 were used.

RESULTS

Organisms were found in 86 (72.88%) out of 118 samples, before sperm preparation; Streptococcus species (n = 40, 46.51% of which 14 were Group D Streptococcus species), Coagulase negative Staphylococcus species (n = 17, 19.76%), Staphylococcus aureus (n = 13, 15.11%), Coliform species (n = 11, 12.79% of which 09 were Escherichia coli) and Corynebacterium species (n = 5, 5.81%). There was a statistically significant reduction of culture positive samples in raw vs. processed samples; in group S, 49 (72.05%) vs. 16 (23.52%) and in group D, 37 (74%) vs. 18 (36%). In group S and D, mean (SD) recovery rates of culture positive vs. culture negative samples were 39.44% (SD-14.02) vs. 44.22% (SD-22.38), P = 0.39 and 52.50% (SD-37.16) vs. 49.58% (SD-40.32), P = 0.82 respectively.

CONCLUSIONS

Both sperm preparation methods significantly reduced bacteria in semen, but total clearance was not achieved. Sperm recovery rate was not affected by bacteriospermia.

Microbiota of the seminal fluid from healthy and infertile men

OBJECTIVE

To explore potential causes of male infertility by determining the composition and structure of commensal bacterial communities in seminal fluids.

DESIGN

Microscopy of Gram-stained semen samples and classification of 16S rRNA gene sequences to determine the species composition of semen bacterial communities.

SETTING

Clinical andrology laboratory and academic research laboratories.

PATIENT(S)

Nineteen sperm donors and 58 infertility patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Classification of 16S rRNA gene sequences, clustering of seminal microbial communities, and multiple statistical tests.

RESULT(S)

High numbers of diverse kinds of bacteria were present in most samples of both sperm donors and infertility patients. The bacterial communities varied widely among subjects, but they could be clustered into six groups based on similarities in composition and the rank abundances of taxa. Overall, there were no significant differences between sperm donors and infertility patients. However, multiple statistical tests showed a significant negative association between sperm quality and the presence of Anaerococcus. The results also indicated that many of the bacterial taxa identified in semen also occur in the vaginal communities of some women, especially those with bacterial vaginosis, which suggests that heterosexual sex partners may share bacteria.

CONCLUSION(S)

Diverse kinds of bacteria were present in the human semen, but there were no significant differences between sperm donors and infertility patients. The presence of Anaerococcus might be a biomarker for low sperm quality.

Multilocus sequence typing (MLST) analysis of Propionibacterium acnes isolates from radical prostatectomy specimens

BACKGROUND

Inflammation is commonly observed in radical prostatectomy specimens, and evidence suggests that inflammation may contribute to prostate carcinogenesis. Multiple microorganisms have been implicated in serving as a stimulus for prostatic inflammation. The pro-inflammatory anaerobe, Propionibacterium acnes, is ubiquitously found on human skin and is associated with the skin disease acne vulgaris. Recent studies have shown that P. acnes can be detected in prostatectomy specimens by bacterial culture or by culture-independent molecular techniques.

METHODS

Radical prostatectomy tissue samples were obtained from 30 prostate cancer patients and subject to both aerobic and anaerobic culture. Cultured species were identified by 16S rDNA gene sequencing. Propionibacterium acnes isolates were typed using multilocus sequence typing (MLST).

RESULTS

Our study confirmed that P. acnes can be readily cultured from prostatectomy tissues (7 of 30 cases, 23%). In some cases, multiple isolates of P. acnes were cultured as well as other Propionibacterium species, such as P. granulosum and P. avidum. Overall, 9 of 30 cases (30%) were positive for Propionibacterium spp. MLST analyses identified eight different sequence types (STs) among prostate-derived P. acnes isolates. These STs belong to two clonal complexes, namely CC36 (type I-2) and CC53/60 (type II), or are CC53/60-related singletons.

CONCLUSIONS

MLST typing results indicated that prostate-derived P. acnes isolates do not fall within the typical skin/acne STs, but rather are characteristic of STs associated with opportunistic infections and/or urethral flora. The MLST typing results argue against the likelihood that prostatectomy-derived P. acnes isolates represent contamination from skin flora.

Uropathogenic E. coli induce different immune response in testicular and peritoneal macrophages: implications for testicular immune privilege

Infertility affects one in seven couples and ascending bacterial infections of the male genitourinary tract by Escherichia coli are an important cause of male factor infertility. Thus understanding mechanisms by which immunocompetent cells such as testicular macrophages (TM) respond to infection and how bacterial pathogens manipulate defense pathways is of importance. Whole genome expression profiling of TM and peritoneal macrophages (PM) infected with uropathogenic E. coli (UPEC) revealed major differences in regulated genes. However, a multitude of genes implicated in calcium signaling pathways was a common feature which indicated a role of calcium-dependent nuclear factor of activated T cells (NFAT) signaling. UPEC-dependent NFAT activation was confirmed in both cultured TM and in TM in an in vivo UPEC infectious rat orchitis model. Elevated expression of NFATC2-regulated anti-inflammatory cytokines was found in TM (IL-4, IL-13) and PM (IL-3, IL-4, IL-13). NFATC2 is activated by rapid influx of calcium, an activity delineated to the pore forming toxin alpha-hemolysin by bacterial mutant analysis. Alpha-hemolysin suppressed IL-6 and TNF-α cytokine release from PM and caused differential activation of MAP kinase and AP-1 signaling pathways in TM and PM leading to reciprocal expression of key pro-inflammatory cytokines in PM (IL-1α, IL-1β, IL-6 downregulated) and TM (IL-1β, IL-6 upregulated). In addition, unlike PM, LPS-treated TM were refractory to NFκB activation shown by the absence of degradation of IκBα and lack of pro-inflammatory cytokine secretion (IL-6, TNF-α). Taken together, these results suggest a mechanism to the conundrum by which TM initiate immune responses to bacteria, while maintaining testicular immune privilege with its ability to tolerate neo-autoantigens expressed on developing spermatogenic cells.

Characteristic male urine microbiomes associate with asymptomatic sexually transmitted infection

BACKGROUND

The microbiome of the male urogenital tract is poorly described but it has been suggested that bacterial colonization of the male urethra might impact risk of sexually transmitted infection (STI). Previous cultivation-dependent studies showed that a variety of non-pathogenic bacteria colonize the urethra but did not thoroughly characterize these microbiomes or establish links between the compositions of urethral microbiomes and STI.

METHODOLOGY/FINDINGS

Here, we used 16S rRNA PCR and sequencing to identify bacteria in urine specimens collected from men who lacked symptoms of urethral inflammation but who differed in status for STI. All of the urine samples contained multiple bacterial genera and many contained taxa that colonize the human vagina. Uncultivated bacteria associated with female genital tract pathology were abundant in specimens from men who had STI.

CONCLUSIONS

Urine microbiomes from men with STI were dominated by fastidious, anaerobic and uncultivated bacteria. The same taxa were rare in STI negative individuals. Our findings suggest that the composition of male urine microbiomes is related to STI.

Testicular infection: microorganisms, clinical implications and host-pathogen interaction

The male reproductive tract harbours effective immune mechanisms to protect the host from invading microorganisms. As the frontline of defence, the innate immune system has evolved receptors that recognise molecular patterns of pathogens to sense infections. These Toll-like receptors discriminate between different pathogen-associated molecules and activate signalling cascades that lead to immune responses, but can also result in tissue destruction leading to fertility disturbances. The testis is unique as it produces a large number of immunogenic cells expressing neo-antigens with no apparent adverse consequences for the majority of men. On the other hand the male gonad appears to be particularly susceptible to tissue damage resulting from infection or inflammatory reactions, a challenge that provides an important task both to clinicians and basic scientists. This review is intended to provide an overview of pathogens relevant in male reproductive tract infection, with a special emphasis on the testis. It also highlights the recent work broadening our understanding of the mechanisms underpinning germ cell loss in the presence of bacteria.

Phenotypic differences between coagulase-negative staphylococci isolated from seminal fluid of healthy men and men suffering from chronic prostatitis syndrome

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The most common causative agents of CPS among Gram-positive bacteria are coagulase-negative staphylococci (CNS). We compared phenotypic properties among CNS isolated from semen of healthy men and patients with CPS. A significantly higher proportion of CPS strains demonstrated inhibition of lysozyme and platelet microbicidal protein. Identifying these phenotypic characteristics in clinical laboratories would be helpful to differentiate which staphylococcal bacteriospermia case should be treated and which should not.

Uropathogenic Escherichia coli block MyD88-dependent and activate MyD88-independent signaling pathways in rat testicular cells

Uropathogenic Escherichia coli (UPEC) is the most common etiological cause of urogenital tract infections and represents a considerable cause of immunological male infertility. We examined TLR 1-11 expression profiles in testicular cells and the functional response to infection with UPEC. All testicular cell types expressed mRNAs for at least two TLRs and, in particular, synthesis of TLR4 was induced in testicular macrophages (TM), Sertoli cells (SC), peritubular cells (PTC), and peritoneal macrophages (PM) after UPEC exposure. Even though MyD88-dependent pathways were activated as exemplified by phosphorylation of mitogen-activated protein kinases in TM, SC, PTC, and PM and by the degradation of IkappaBalpha and the nuclear translocation of NF-kappaB in PTC and PM, treatment with UPEC did not result in secretion of the proinflammatory cytokines IL-1alpha, IL-6, and TNF-alpha in any of the investigated cells. Moreover, stimulated production of these cytokines by nonpathogenic commensal E. coli or LPS in PM was completely abolished after coincubation with UPEC. Instead, in SC, PTC, TM, and PM, UPEC exposure resulted in activation of MyD88-independent signaling as documented by nuclear transfer of IFN-related factor-3 and elevated expression of type I IFNs alpha and beta, IFN-gamma-inducible protein 10, MCP-1, and RANTES. We conclude that in this in vitro model UPEC can actively suppress MyD88-dependent signaling at different levels to prevent proinflammatory cytokine secretion by testicular cells. Thus, testicular innate immune defense is shifted to an antiviral-like MyD88-independent response.

Bacteria trigger oxygen radical release and sperm lipid peroxidation in in vitro model of semen inflammation

OBJECTIVE

To assess the in vitro effect of five bacterial strains isolated from semen samples (Escherichia coli, Staphylococcus haemolyticus, Streptococcus oralis, Bacteroides ureolyticus, and Ureaplasma urealyticum) on reactive oxygen intermediate (ROI) release and lipid sperm membrane peroxidation in the coincubated suspensions of white blood cells (WBC) with spermatozoa.

DESIGN

An in vitro model of semen infection.

SETTING

Basic research laboratory.

PATIENT(S)

Healthy normozoospermic volunteers and healthy blood donors.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Chemiluminescent assay was used to evaluate ROI generation by WBC. Malondialdehyde (MDA) concentration was determined in sperm lysates using high-performance liquid chromatography.

RESULT(S)

Of the bacterial strains tested, B. ureolyticus, S. haemolyticus, and E. coli caused the greatest damage to sperm membrane lipids. An increase in MDA levels in sperm lysates was a natural consequence of bacteria-induced ROI generation. The WBC usually enhanced harmful activity of the infectious agent toward the cell membranes.

CONCLUSION(S)

The harmful effect of bacteria on spermatozoa depends on the type and species of microorganisms invading, colonizing, or infecting the male genital tract and is associated with the accompanying oxidative stress. The presence of leukocytes in semen appears to be the additional factor enhancing the sperm lipid membrane peroxidation, which may affect the fertility status.

Coryneform bacteria in semen of chronic prostatitis patients

Our aim was to compare the presence and species composition of coryneform bacteria in chronic prostatitis patients and controls. Semen of 50 men with inflammatory prostatitis and 59 controls (without pelvic pain/discomfort complaints and leukocytospermia) was investigated. First-catch urine was additionally investigated in 36 men (30 with and 6 without prostatitis). Coryneform bacteria were found in semen of 76% men with inflammatory prostatitis and 83% controls. More than half of the isolates were identified as Corynebacterium seminale. Prostatitis patients with severe leukocytospermia (>1 million white blood cells per ml) harboured significantly more Corynebacterium group G (33% vs. 2%, p = 0.0003) and Arthrobacter sp. (17% vs. 2%, p = 0.03) in comparison with controls. Nine species of coryneforms with high concentration (>or=10,000 CFU per ml) were found in prostatitis patients as against only four species in controls. Half of the men harboured corynebacteria in semen as well as in urine, 22% of men in semen only, and 3% in urine only. The total concentration of coryneforms was greater in semen than in urine (median 5000 vs. 100 CFU per ml, p = 0.053). We suggest that although coryneforms are generally considered as saprophytes, they are not uniform and some species (Corynebacterium group G and Arthrobacter sp.) may be associated with inflammatory prostatitis.

Polymerase chain reaction-based identification of Propionibacterium acnes types isolated from the male urinary tract: evaluation of adolescents, normal adults and men with prostatic pathology

OBJECTIVE

To assess whether colonization of the male urinary tract with Propionibacterium acnes, in particular types IB and II (which are associated with inflammation in radical prostatectomy specimens and might be involved in the development of prostate cancer), is associated with prostate disease, and thus to develop a urine test to detect men at risk of prostate disease.

PATIENTS, SUBJECTS AND METHODS

We developed the first polymerase chain reaction (PCR)-based technique for identifying P. acnes types IA, IB and II, and used this in combination with selective culture medium to compare the prevalence of these subtypes in the urinary tract of adolescent males, healthy adult men and patients with confirmed prostate pathology.

RESULTS

P. acnes types IB and II were no more prevalent in the urinary tract of patients with prostate pathology than in normal control men. However, the prevalence of types IB and II appeared to be higher in adult men (at 11 of 15 and six of 15, respectively) than in adolescents (two of six and one of six), suggesting an age-related increase. Comparison of urinary tract and facial skin P. acnes from three subjects showed that type IA was more often predominant on facial skin, whereas types IB or II were more often predominant in the urinary tract.

CONCLUSIONS

A urine test might not be useful for detecting men with prostatic P. acnes infection and thus at greater risk of associated prostate disease. However, this work validated our technique for detecting and identifying the three P. acnes subtypes, and identified some interesting trends worth further investigation.

Toll-like receptor 4 in rat prostate: modulation by testosterone and acute bacterial infection in epithelial and stromal cells

The prostate gland is the most inflammation-prone organ in the male reproductive tract. However, little information is available regarding the immunobiology of this gland. Toll-like receptor 4 (TLR4) is considered to be a major sensor of danger signals and a key trigger of the innate immune responses. TLRs have also been implicated in the development of different inflammatory diseases in organs in which epithelial-stromal interactions are critical for homeostasis. The purpose of this work was to evaluate the presence and regulation of TLR4 in the rat prostate. Western blot and immunocytochemical studies revealed that constitutive expression of TLR4 in the rat ventral prostate was localized in the epithelial cells, mainly associated with the rough endoplasmic reticulum, as well as in smooth muscle cells in the stroma. In addition, increased concentrations of TLR4 were found in castrated rats, predominantly in hypertrophied smooth muscle cells. On the other hand, using a bacterial prostatitis model, we observed an increment in the TLR4 cytoplasmic content and migration of this receptor to the apical plasmatic membranes of epithelial cells at 24 h and 48 h post-infection. These findings suggest that the prostate gland is able to recognize pathogens and to initiate immune responses. In addition, TLR4 appears to be implicated in the vital stromal-epithelial interactions that maintain prostate homeostasis during prostatitis, as well as following androgen deprivation.

Links between Propionibacterium acnes and prostate cancer

Incidental foci of prostate cancer are found at autopsy in 30% of men in their third decade, and by their eighth decade more than 75% have histological evidence of cancer. This unprecedented cancer prevalence points to a ubiquitous causative agent or perhaps an interaction between multiple common carcinogenic cofactors. We propose that one of these carcinogens is Propionibacterium acnes. Several characteristics of prostate cancer suggest the involvement of an infectious agent and we provide evidence that P. acnes is an excellent candidate. We have cultured P. acnes from a substantial proportion of prostate glands containing cancer and shown a significant positive association with prostatic inflammation. P. acnes is well suited to cause persistent, low-grade infection involving a marked inflammatory response and the P. acnes subtypes most frequently associated with prostate cancer become highly prevalent in the urinary tract of males following puberty.

Bacterial flora of the low male genital tract in patients consulting for infertility

The physiological aerobic bacterial flora of the low male genital tract was determined. This prospective study was performed on 600 semen specimens collected from 543 asymptomatic males consulting for infertility. Semen cultures were sterile in 28.8%, with a polymicrobial flora and/or absence or low titres of Ureaplasma urealyticum in 49.3%, and with one or two aerobic and facultative bacteria > or =1 x 10(3) CFU ml(-1) and/or U. urealyticum with titres > or =10(4) CCU ml(-1) (colour changing units) in 21.8%. In standard aerobic cultures, Gardnerella vaginalis was the most commonly isolated species (26.1%), followed by coagulase-negative staphylococci (15.7%) and Streptococcus anginosus (14.2%). Ureaplasma urealyticum was absent in 84.5% of semen samples, but when recovered, high (> or =10(4) CCU ml(-1)) and low titres (< or =10(3) CCU ml(-1)) were counted in 7.2% and 8.3% respectively. Of 48 patients, the follow-up of semen cultures showed marked variations in time. This study shows that (i) there was no relationship between the bacterial flora and the leucocytospermia; (ii) low titres of U. urealyticum in semen were not associated with a disturbance of the ecosystem; (iii) the critical threshold for U. urealyticum should be raised to > or =10(4) CFU ml(-1) and (iv) a positive semen culture should be repeated before any treatment.

PROPIONIBACTERIUM ACNESASSOCIATED WITH INFLAMMATION IN RADICAL PROSTATECTOMY SPECIMENS: A POSSIBLE LINK TO CANCER EVOLUTION?

PURPOSE

Inflammation is commonly observed in the prostate gland and has been implicated in the development of prostate cancer. The etiology of prostatic inflammation is unknown. However, the involvement of a carcinogenic infectious agent has been suggested.

MATERIALS AND METHODS

Prostatic tissue from 34 consecutive patients with prostate cancer was cultured to detect the presence of bacterial agents. Prostatic inflammation was assessed by histological examination of wholemount tissue sections.

RESULTS

The predominant microorganism detected was Propionibacterium acnes, found in 35% of prostate samples. A significantly higher degree of prostatic inflammation was observed in cases culture positive for P. acnes (p =0.007). P. acnes was separated into 3 groups based on cell surface properties, phenotype and genetic grouping. All skin control isolates were classified as group 1 whereas most prostatic isolates were classified as groups 2 and 3.

CONCLUSIONS

P. acnes has been isolated from prostatic tissues in men who underwent radical prostatectomy for localized cancer and has been shown to be positively associated with prostatic inflammation. This inflammation may then be linked to the evolution of carcinoma. Furthermore, organisms infecting these patients with prostate cancer differ genetically and phenotypically from the commonly identified cutaneous P. acnes isolates, suggesting that specific subtypes may be involved in development of prostatic inflammation.

Molecular identification of the first human isolate belonging to the Veillonella ratti-Veillonella criceti group based on 16S rDNA and dnaK gene sequencing

Anaerobic gram-negative cocci belonging to the genus Veillonella are currently subdivided into eight species. Among them, four have been isolated either from human flora or from clinical samples during infectious processes: Veillonella atypica, V. dispar, V. parvula and V. montpellierensis. To date, the four other species have only been found in animals. In particular, V. ratti and V. criceti, since their characterization, have been exclusively reported from mouth and intestine of rodents. We report here for the first time a human isolate belonging to the V. ratti-V. criceti group recovered in mixed aerobic-anaerobic flora from a semen sample in a 24-year-old man attending the urology unit of our hospital for infertility. Identification of the isolate was based on 16S ribosomal DNA and dnaK gene sequencing. Since then, two strains of Veillonella sp. recovered from semen samples remained unidentified to the species level, and 16S rDNA-based phylogenetic analysis revealed that they might represent novel taxa within the genus Veillonella. Taken together, these observations suggest that host restriction may not exist in the genus Veillonella and that bacterial diversity remains underestimated both within this genus and in human semen.

Male genital hygiene beliefs and practices in Nairobi, Kenya

OBJECTIVES

Attitudes and practices concerning genital hygiene may influence topical microbicide use by men. This study examines knowledge and behaviours related to hygiene, genital hygiene, circumcision and hygiene, and to genital hygiene before and after sex among men in Nairobi, Kenya.

METHODS

We conducted 463 interviews of men recruited by respondent driven sampling techniques and 10 focus group discussions with a subsample of 100 volunteers from this group. Men were asked individual quantitative survey and qualitative group discussion questions about general hygiene behaviours, genital hygiene, and the temporal relation of genital hygiene behaviours to sexual encounters.

RESULTS

Bathing once daily was associated with education, income, and inside tap water. Genital washing aside from regular bathing and washing before sex ever were negatively associated with bathroom crowding. Genital hygiene before the most recent sexual encounter was uncommon and negatively associated with HIV risk perception, bathroom crowding, and ethnicity. Men believed genital hygiene before sex would arouse suspicions of infidelity or cool sexual ardour. Genital hygiene after sex was associated with education, religion, and having inside tap water. Genital hygiene after the most recent sexual encounter was associated with age, income, and with men having at least one child.

CONCLUSIONS

Genital hygiene behaviours were associated with resource access factors and group discussions suggest that they are modulated by interactions in sexual partnerships. Topical microbicides may improve hygiene before and after sex.

High incidence of oligozoospermia and teratozoospermia in human semen infected with the aerobic bacterium Streptococcus faecalis

Bacterial culture of semen samples from 100 male partners in infertile couples revealed the presence of aerobic bacteria in 49 cases. Streptococcus faecalis (Enterococcus) was isolated from 53%, micrococci species from 20% and alpha-haemolytic streptococci from 16% of the infected samples. The incidence of oligozoospermia and teratozoospermia was significantly (P < 0.05) higher in men whose semen samples contained S. faecalis than those whose semen samples contained micrococci or alpha-haemolytic streptococci or those that did not contain bacteria. The mean sperm concentration, as well as the mean percentage of morphologically normal spermatozoa, was significantly (P < 0.03) lower in semen infected with S. faecalis compared with that containing micrococci or alpha-haemolytic streptococci and the uninfected samples. There is a high incidence of semen infection with S. faecalis, and it is associated with compromised semen quality in terms of sperm concentration and morphology. The presence of micrococci or alpha-haemolytic streptococci does not appear to have any detrimental effect on sperm quality.

Are seminal fluid microorganisms of significance or merely contaminants?

OBJECTIVE

To determine the contribution of urethral and skin flora to seminal fluid cultures and the relation between bacteriospermia and seminal leukocytes.

DESIGN

Prospective study.

SETTING

IVF-ET unit at a university teaching hospital.

PATIENT(S)

Sixty men starting an IVF-ET program.

INTERVENTION(S)

Culture of sequential first-catch urine, midstream urine, and semen samples with evaluation of seminal leukocytes.

MAIN OUTCOME MEASURE(S)

A comparison of microbes from first-catch urine, midstream urine, and semen samples and the correlations of seminal microbes, elevated leukocyte concentrations, and pregnancy.

RESULT(S)

Microorganisms were detected in 37% of first-catch urine samples, 27% of midstream urine samples, and 51% of semen samples. Most microorganisms were gram-positive microbes and were common to both urine and semen samples. Mean and median leukocyte concentrations were 0.98 x 10(6)/mL and 0.10 x 10(6)/mL, respectively. There was no correlation between seminal microbes and raised leukocytes or between leukocytospermia and/or bacteriospermia and pregnancy.

CONCLUSION(S)

Microorganisms are commonly found in insignificant quantities in the semen of asymptomatic men. The frequent isolation of gram-positive microbes common to both urine and semen and the absence of a correlation with raised leukocyte concentrations suggest that bacteriospermia most commonly represents contamination.

Bacterial contamination and sperm recovery after semen preparation by density gradient centrifugation using silane-coated silica particles at different g forces

The effects of density gradient centrifugation through silane-coated silica particles (PureSperm) using 100, 200, 300 and 500 g on bacterial contamination of sperm samples and recovery of motile spermatozoa from sperm samples were investigated with conventional culturing techniques and microscopic visual assessment. The recovery of motile spermatozoa was variable and was not improved using 500 g compared to the recommended 300 g. The bacterial contamination was highly decreased by gradient centrifugation through PureSperm and was almost abolished when strict aseptic techniques were used, with changes to sterile Pasteur pipettes and tubes prior to washing procedures.

Testicular sperm aspiration and intracytoplasmic sperm injection for persistent infection of the ejaculate

OBJECTIVE

To report the successful use of testicular sperm aspiration and intracytoplasmic sperm injection in the presence of an Escherichia coli-infected ejaculate that previously caused repeated embryo degeneration.

DESIGN

Case report.

SETTING

University medical center.

PATIENT(S)

A 38-year-old woman who did not conceive for 6 years with repeated IVF attempts. Escherichia coli was isolated from both the oocyte culture dish and her male partner's ejaculate.

INTERVENTION(S)

Testicular sperm aspiration and intracytoplasmic sperm injection followed by ET.

MAIN OUTCOME MEASURE(S)

Clinical outcome.

RESULT(S)

Establishment of a pregnancy delivered at term.

CONCLUSION(S)

Patients undergoing IVF treatment who have repeated embryo degeneration caused by bacterial infection originating in the ejaculate may be treated successfully with testicular sperm aspiration and intracytoplasmic sperm injection.