A systematic review of the correlation between Trichomonas vaginalis infection and infertility

Trichomoniasis and Other Sexually Transmitted Parasitic Diseases in Women

Parasitic sexually transmitted infections are spread through sexual contact (vaginal, oral, and/or anal sex). The majority of parasitic STIs involve protozoan pathogens (ie, Trichomonas vaginalis, Entamoeba histolytica, and Giardia duodenalis ); however, ectoparasitic infections ( Pthirus pubis and Sarcoptes scabiei ) are also included in this group. The purpose of this review is to provide a comprehensive summary of the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of parasitic sexually transmitted infections, with a particular focus on their impact on women.

Prevalence of Trichomonas vaginalis Among Women in the Chinese Population: A Systematic Review and Meta-Analysis

Trichomonas vaginalis (TV) is the most common non-viral sexually transmitted infection (STI) among women worldwide. However, there is little information available regarding the burden of trichomoniasis infection among Chinese women. The aim of the present study is to assess the status of trichomoniasis in China. To address this gap, we searched seven databases for relevant studies published from their inception to June 2024. The overall prevalence of T. vaginalis in China was determined to be 6.31% with a high level of heterogeneity (I2 = 99.68%). Subgroup analysis also demonstrated a statistically significant association between the T. vaginalis prevalence in the type of population, age range, year, residential status, and province. Among these, sex workers are the most prominent with 12.16%. Meta-regression analysis indicated that the infection rate of T. vaginalis among Chinese women had not shown a significant decline over time (p = 0.2919). Therefore, it continues to be a public health issue that should not be overlooked. Sex workers and rural women have a relatively higher infection rate of trichomoniasis, and this is largely associated with sexual safety awareness and hygiene conditions. Our findings provide crucial information for healthcare authorities and can shed light on the prevention strategies for trichomoniasis in China.

Trichomonas vaginalis adhesion protein 33 (TvAP33) promotes HPV infection by upregulating the expression of HPV membrane receptor molecules

An increasing number of studies have identified Trichomonas vaginalis (T. vaginalis) as a risk factor for human papillomavirus (HPV) infection, yet experimental data and the mechanisms involved are still lacking. Wild-type and T. vaginalis adhesion protein 33 (TvAP33) knockdown T. vaginalis were used to infect HaCaT cells and the vaginal tissue of mice, while HaCaT cells were also transfected to overexpress TvAP33. The effects of TvAP33 on the expression of HPV membrane receptor molecules and HPV infection were assessed. Infection of HaCaT cells with low expression of HPV membrane receptor molecules by T. vaginalis with reduced TvAP33 expression was conducted to analyze whether TvAP33 influences HPV infection through HPV membrane receptor molecules. In this study, we found that T. vaginalis significantly enhances HPV invasion into HaCaT cells and the mouse vagina while also increases the expression of HPV receptor molecules CD151 and HSPG2. Reducing the expression of TvAP33 led to a significant decrease in both HPV invasion rate and CD151/HSPG2 expression. Conversely, overexpressing TvAP33 in HaCaT cells resulted in a notable increase in HPV invasion and CD151/HSPG2 expression. Additionally, the simultaneous reduction of TvAP33 expression in T. vaginalis and CD151/HSPG2 expression in HaCaT cells further decreased HPV invasion rates. These findings suggest that TvAP33 promotes HPV infection by upregulating CD151 and HSPG2 expression. This study not only confirms, through both in vivo and in vitro experiments, that T. vaginalis facilitates HPV infection but also explores the mechanism by which TvAP33 enhances HPV infection by regulating HPV receptor expression. These results provide a theoretical basis for understanding the mechanisms of T. vaginalis co-infection with HPV.

Antimicrobial Resistance in Curable Sexually Transmitted Infections

PURPOSE OF REVIEW

Antimicrobial resistance in sexually transmitted infections (STIs) has become an urgent global public health threat, raising the specter of untreatable infections. This review summarizes the determinants of resistance among the five most common curable STIs Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Treponema pallidum, and Trichomonas vaginalis, as well as strategies to mitigate the spread of resistance.

RECENT FINDINGS

Genetic mutations are key drivers of resistance for N. gonorrhoeae and M. genitalium. Resistance in T. vaginalis can also occur because of genetic mutations, yet differential regulation of genes critical in antibiotic metabolism as well as co-infection with organisms that inactivate therapy play important roles. While resistance in C. trachomatis and T. pallidum has not been a substantial clinical concern, resistance selection via the continued widespread use of antimicrobials remains possible. While resistance determinants are diverse and differ by pathogen, the strategies required to mitigate the continued emergence of resistance are similar: prevention of infection and treatment diversification. Underpinning those strategies, surveillance remains essential for monitoring and responding to the threat of drug-resistant infections.

Trichomoniasis in Men: A Neglected Factor in Male Infertility?

PURPOSE

This study is aimed to detect the frequency of trichomoniasis, a sexually transmitted infection caused by an anaerobic protozoan Trichomonas vaginalis, in men referred to the Fertility and Infertility Research Center Hamadan University of Medical Sciences.

METHODS

In this cross-sectional study, a group of 197 male volunteers who sought medical attention for issues related to infertility participated. The urine and semen samples were collected in sterile conditions. Both urine and semen sediment were promptly examined under a microscopy to detect the presence of motile trophozoites. Subsequently, 50 µl of urine sediment were inoculated into the Dorset culture medium, whereas 50 µl of semen sediment were inoculated into the Diamond culture (TYI-S-33) and incubated at 35.5oC. Finally, the processed urine samples were used for molecular analysis.

RESULTS

The investigated subjects had an average age ranging from 36 to 40 years. There were 181 volunteers with fertility issues, outnumbering the 16 individuals with normal fertility. Spermogram analysis showed that 48% of participants had non-motile or progressive sperms, and 48% had abnormalities in sperm morphology. T. vaginalis was not detected through microscopic assessment, but PCR and sequence analysis revealed one case in a 33-year-old infertile individual, who had only 0.3% normal sperm with 19% motility. The isolated T.vaginalis was found to have the G genotype based on the sequencing analysis.

CONCLUSION

Trichomoniasis in males was considered unimportant, with the belief that it would improve on its own. This study suggests that parasites can be considered as one of the male infertility factors, however, the impact is not fully understood. This investigation confirmed the effectiveness of molecular techniques in detecting trichomoniasis in males.

Establishment of a programmatic detection method for Trichomonas vaginalis based on double antibody sandwich ELISA targeting TvCP39 antigen

BACKGROUND

Trichomonas vaginalis (T. vaginalis) is a common sexually transmitted parasite that colonizes the human urogenital tract. Programmed and precise detection of T. vaginalis is a key step in preventing and treating trichomoniasis. However, the current detection methods of T. vaginalis, including wet mount microscopy, culture, nested PCR, loop-mediated isothermal amplification, and recombinant enzyme polymerase amplification, have some shortcomings. Therefore, it is urgent to establish a programmed, sensitive, and specific method for detecting T. vaginalis.

METHODS

T. vaginalis cysteine protease 39 (TvCP39) was expressed in segments as TvCP39-1 and TvCP39-2, and the polyclonal antibodies were prepared by immunizing rats and rabbits. The concentration of the polyclonal antibodies of anti-rTvCP39-2 and anti-rTvCP39-1 was determined by square matrix titration. The sensitivity and specificity of double antibody sandwich ELISA were analyzed and evaluated by detecting rTvCP39 and T. vaginalis excretory-secretory proteins (TvESPs) diluted in multiple ratios and detecting excretory-secretory proteins of T. vaginalis and other pathogens, respectively. The detection efficiency of wet mount microscopy, nested PCR, and double antibody sandwich ELISA was compared by testing sixty-two clinical samples from vaginal secretions.

RESULTS

The natural TvCP39 protein could be specifically recognized by anti-rTvCP39-1 and anti-rTvCP39-2 antibodies. The concentrations of anti-rTvCP39-2 and anti-rTvCP39-1 polyclonal antibodies were determined to be 0.58 μg/mL and 0.45 μg/mL, respectively. The results of the sensitivity test showed that the detection limits of rTvCP39 and TvESPs by double antibody sandwich ELISA were 1.76 ng/mL and 107.125 μg/mL, respectively. The specificity test results showed that the double antibody sandwich ELISA had a high specificity for the detection of T. vaginalis and did not cross-react with Escherichia coli, Staphylococcus aureus, Candida albicans, and Lactobacillus. The positive detection rate of clinical samples by double antibody sandwich ELISA was higher than that by wet mount microscopy, and was the same as nested PCR. The sensitivity of double antibody sandwich ELISA was consistent with that of nested PCR. The coincidence rate between double antibody sandwich ELISA and nested PCR was 100% (Kappa=1, P < 0.001).

CONCLUSION

The double antibody sandwich ELISA detection method for T. vaginalis established in this study had the advantages of high sensitivity and specificity, and did not require the extraction of genomic DNA. This programmatic and simple detection method was suitable for batch testing of clinical samples and exhibited the potential value in the treatment and prevention of trichomoniasis.

High frequency of point mutations in the nitroreductase 4 and 6 genes of Trichomonas vaginalis associated with metronidazole resistance

Trichomoniasis, a globally distributed sexually transmitted infection, is caused by the urogenital parasite Trichomonas vaginalis Donné, 1836 affecting both women and men. The treatment of choice is metronidazole (MTZ). In the present study, 15 samples of vaginal discharge and urine were analysed by sequencing nitroreductase genes (ntr4 and ntr6). An in silico model was structured to illustrate the location of point mutations (PM) in the protein. The ntr4 gene presented four PMs: G76C (10/10), C213G (9/10), C318A (5/10) and G424A (1/10), while the ntr6 gene had eight PMs; G593A (13/13) the most frequent, G72T and G627C, both in 8/13. The PM C213G and A438T generated a stop codon causing a truncated nitroreductase 4 and 6 protein. Docking analysis demonstrated that some models had a decrease in binding affinity to MTZ (p < 0.0001). A high frequency of mutations was observed in the samples analysed that could be associated with resistance to MTZ in Chile.

Detection of Trichomonas vaginalis by microscopy and molecular methods in women referred to health centers in Tabriz, Northwest Iran

Trichomoniasis is a parasitic disease that affects the human reproductive and urinary systems, representing a substantial non-viral sexually transmitted infection worldwide. Given its impact on reproductive health, and the limited available information on the prevalence of Trichomonas vaginalis, this study aimed to evaluate the prevalence of T. vaginalis among women referred to health centers in Tabriz, Northwest Iran. Study was conducted on 448 suspicious women who attended to 29Bahman hospital in Tabriz, Northwest Iran, during September 2020 to September 2021. Demographic data were collected according to the study protocol. Vaginal discharges were obtained using sterile swabs, and the prevalence of T. vaginalis was determined using Papanicolauo staining and PCR method. Among the 448 cases studied, 48 (10.7%) samples were suspected as a T. vaginalis infection, while 4 (0.89%) confirmed using the PCR method. The mean age of infected individuals was 41.7 ± 9.4 years. No statistical correlation was observed between inflammation, method of contraception and infection (p = 0.8). The present study revealed a relatively low prevalence of T. vaginalis infection within the study population. Additionally, the utilization of the PCR method can be beneficial in confirming suspected samples.

Trichomonas vaginalis: Monolayer and Cluster Formation-Ultrastructural Aspects Using High-Resolution Scanning Electron Microscopy

Trichomonas vaginalis is an extracellular protozoan parasite that causes human trichomoniasis, a sexually transmitted infection (STI) that affects approximately 270 million people worldwide. The phenomenon of T. vaginalis adhesion to inert substrates has been described in several reports. Still, very few studies on cluster formation have been conducted, and more detailed analyses of the contact regions between the parasites' membranes in these aggregate formations have not been carried out. The present study aims to show that T. vaginalis forms a tight monolayer, similar to an epithelium, with parasites firmly adhered to the culture flask bottom by interdigitations and in the absence of host cells. In addition, we analyzed and compared the formation of the clusters, focusing on parasite aggregates that float in the culture flasks. We employed various imaging techniques, including high-resolution scanning electron microscopy, transmission electron microscopy, cytochemistry, TEM tomography, and dye injection. We analyzed whether the monolayer behaves as an epithelium, analyzing cell junctions, cell communication, and ultrastructural aspects, and concluded that monolayer formation differs from cluster formation in many aspects. The monolayers form strong adhesion, whereas the clusters have fragile attachments. We did not find fusion or the passage of molecules between neighbor-attached cells; there is no need for different strains to form filopodia, cytonemes, and extracellular vesicles during cluster and monolayer formation.

[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.

Trichomonas vaginalis adhesion protein 65 (TvAP65) modulates parasite pathogenicity by interacting with host cell proteins

Trichomonas vaginalis (T. vaginalis) is a widespread and important sexually transmitted pathogen. Adherence to the surface of the host cell is the precondition forthis parasite's parasitism and pathogenicity. Adhesion protein 65 (TvAP65) plays a key role in the process of adhesion. However, how TvAP65 mediates the adhesion and pathogenicity of T. vaginalis to host cellsis unclear. In this study, we knocked down the expression of TvAP65 in trophozoites by small RNA interference. The number of T. vaginalis trophozoites adhering to VK2/E6E7 cells was decreased significantly, and the inhibition of VK2/E6E7 cells proliferation and VK2/E6E7 cells apoptosis and death induced by T. vaginalis were reduced, after the expression of TvAP65 was knocked down. Animal challenge experiments showed that the pathogenicity of trophozoites was decreased by passive immunization with anti-rTvAP65 PcAbs or blocking the TvAP65 protein. Immunofluorescence analysis showed that TvAP65 could bind to VK2/E6E7 cells. In order to screen the molecules interacting with TvAP65 on the host cells, we successfully constructed the cDNA library of VK2/E6E7 cells, and thirteen protein molecules interacting with TvAP65 were screened by yeast two-hybrid system. The interaction between TvAP65 and BNIP3 was further confirmed by coimmunoprecipitation and colocalization. When both TvAP65 and BNIP3 were knocked down by small RNA interference, the number of T. vaginalis adhering to VK2/E6E7 cells and the inhibition of VK2/E6E7 cells proliferation were significantly lower than those of the group with knockdown of TvAP65 or BNIP3 alone. Therefore, the interaction of TvAP65 and BNIP3 in the pathogenesis of T. vaginalis infecting host cells is not unique and involves other molecules. Our study elucidated that the interaction between TvAP65 and BNIP3 mediated the adhesion and pathogenicity of T. vaginalis to host cells, provided a basis for searching for the drug targets of anti-T. vaginalis, and afforded new ideas for the prevention and treatment of trichomoniasis.

Deficiency of hydrogen sulfide production and pregnancy rate in an experimental model: Association with preterm delivery

PROBLEM

Pro-inflammatory phenomena drive preterm delivery (PTD). Hydrogen sulfide is a gasotransmitter with anti-inflammatory properties produced through the activity of the enzyme cystathionine-γ-lyase (CSE), and its impact was studied in models of normal delivery and PTD in mice.

METHOD OF STUDY

Female CSE+/+ and CSE-/- mice were mated with male CSE+/+ mice; mating was done with drinking water unsupplemented and supplemented with cysteine. The pregnancy rate was monitored. PTD was induced by the intraperitoneal injection of bacterial lipopolysaccharide (LPS) on day 14.5 of pregnancy. Mice were sacrificed for tissue collection and splenocyte isolation after 6 and 12 h. Isolated splenocytes were stimulated for the production of tumor necrosis factor-alpha (TNFα), interleukin (IL)-10 and interferon-gamma (IFNγ); TNFα and vascular endothelial growth factor (VEGF) were measured in the fetuses and the placenta.

RESULTS

The successful pregnancy rate was lower in CSE-/- mice and it was restored with cysteine supplementation. CSE deficiency was associated with higher tissue concentrations of TNFα in the fetuses, attenuated IL-10 responses and higher IFNγ production from splenocytes. CSE deficiency was not associated with PTD. Following PTD induction, CSE-/- mice did not show attenuated IL-10 responses but the production of TNFα and IFNγ was lowered over-time; placental VEGF was also increased over-time.

CONCLUSIONS

CSE deficiency has an unfavorable impact on pregnancy. H2 S deficiency through CSE does not drive PTD but mediates pro-inflammatory phenomena in fetuses.

Transcriptional profile of Trichomonas vaginalis in response to metronidazole

BACKGROUND

Trichomoniasis caused by Trichomonas vaginalis, combined with its complications, has long frequently damaged millions of human health. Metronidazole (MTZ) is the first choice for therapy. Therefore, a better understanding of its trichomonacidal process to ultimately reveal the global mechanism of action is indispensable. To take a step toward this goal, electron microscopy and RNA sequencing were performed to fully reveal the early changes in T. vaginalis at the cellular and transcriptome levels after treatment with MTZ in vitro.

RESULTS

The results showed that the morphology and subcellular structures of T. vaginalis underwent prominent alterations, characterized by a rough surface with bubbly protrusions, broken holes and deformed nuclei with decreased nuclear membranes, chromatin and organelles. The RNA-seq data revealed a total of 10,937 differentially expressed genes (DEGs), consisting of 4,978 upregulated and 5,959 downregulated genes. Most DEGs for the known MTZ activators, such as pyruvate:ferredoxin oxidoreductase (PFOR) and iron-sulfur binding domain, were significantly downregulated. However, genes for other possible alternative MTZ activators such as thioredoxin reductase, nitroreductase family proteins and flavodoxin-like fold family proteins, were dramatically stimulated. GO and KEGG analyses revealed that genes for basic vital activities, proteostasis, replication and repair were stimulated under MTZ stress, but those for DNA synthesis, more complicated life activities such as the cell cycle, motility, signaling and even virulence were significantly inhibited in T. vaginalis. Meanwhile, increased single nucleotide polymorphism (SNP) and insertions - deletions (indels) were stimulated by MTZ.

CONCLUSIONS

The current study reveals evident nuclear and cytomembrane damage and multiple variations in T. vaginalis at the transcriptional level. These data will offer a meaningful foundation for a deeper understanding of the MTZ trichomonacidal process and the transcriptional response of T. vaginalis to MTZ-induced stress or even cell death.

Trichomoniasis

Trichomoniasis is the most common nonviral sexually transmitted infection worldwide. It has been associated with a variety of adverse sexual and reproductive health outcomes for both men and women. In this review, the authors discuss updates in its epidemiology, pathophysiology, clinical significance, diagnosis, and treatment.