An emerging mycoplasma associated with trichomoniasis, vaginal infection and disease

Characterization of Actin-based Genotypes and Mycoplasma Endosymbionts of Trichomonas vaginalis Isolated in Sapporo, Japan

PURPOSE

Trichomonas vaginalis is a causative agent of common non-viral sexually transmitted infections worldwide. However, the biological features, such as genotypes and endosymbionts, of T. vaginalis isolated in Japan remain unclear. The aim of this study was to characterize the actin-based genotypes and the endosymbionts of T. vaginalis isolated in Sapporo, Japan.

METHODS

Three T. vaginalis clinical strains were isolated in Sapporo, Japan between 2019 and 2022. Actin-based genotyping was conducted by sequencing and phylogenetic analyses. The endosymbionts, such as Mycoplasma sp. and Trichomonasvirus, were detected using PCR and RT-PCR, respectively. Furthermore, the detected Mycoplasma spp. were identified using 16S rRNA gene sequencing.

RESULTS

Of the three T. vaginalis strains, two belonged to genotype E, whereas one was genotype G as determined by actin-based genotyping. Two of the T. vaginalis strains harbored Mycoplasma spp. Using nearly full-length 16S rRNA gene sequencing, both were identified as Candidatus Mycoplasma girerdii. In contrast, the Trichomonasvirus was not found in the T. vaginalis strains.

CONCLUSION

To our knowledge, this is the first report on the characterization of actin-based genotypes and the presence of endosymbiotic Ca. M. girerdii in T. vaginalis strains in Japan. Thus, this study will provide an important impetus for future research.

Chitosan-coated miconazole as an effective anti-inflammatory agent for the treatment of postoperative infections in obstetrics and vaginal yeast infection control on in vitro evaluations

People with immune deficiency are at risk of developing infections caused by several bacterial and fungal species. In this work, chitosan-coated miconazole was developed by a simple sol-gel method. Miconazole is considered an effective drug to treat vaginal infection-causing bacteria and fungi. The coating of chitosan with miconazole nitrate showed the highest drug loading efficiency (62.43%) and mean particle size (2 μm). FTIR spectroscopic analysis confirmed the entrapment of miconazole nitrate into chitosan polymer. The antifungal result demonstrated that MN@CS microgel possessed notable anti-Aspergillus fumigatus and Candida albicans activity in lower doses. Antibacterial activity results revealed excellent bacterial growth inhibition of MN@CS microgel towards human skin infectious pathogens Escherichia coli and Staphylococcus aureus. The biocompatibility studies of In vitro cell viability and Artemia salina lethality assay suggested that MN@CS microgel is more biosafe and suitable for human external applications. In the future, it will be an efficient anti-inflammatory agent for the treatment of vaginal infections.

Evolutionary conservation of Trichomonas-mycoplasma symbiosis across the host species barrier

Introduction

The protozoan parasite Trichomonas vaginalis is the most common cellular sexually transmitted disease in humans, and the closely related species Trichomonas gallinae is an avian parasite of ecological and economic importance. Phylogenetic evidence suggests T. vaginalis arose during bird to human transmission of a T. gallinae-like ancestor. Trichomonas vaginalis shares a strong clinical association with the independent sexually transmitted pathogen Metamycoplasma (formerly Mycoplasma) hominis, and the uncultured bacterium "Candidatus Malacoplasma (formerly Mycoplasma) girerdii," with the latter association being an order of magnitude stronger. Both bacterial species have been shown to profoundly influence T. vaginalis growth, energy production and virulence-associated mechanisms.

Methods

Evidence for a novel Malacoplasma sp. was discovered by in vivo Illumina metatranscriptomics sequencing of the T. gallinae-infected pigeon mouth. We leveraged published 16S rDNA profiling data from digestive tract of 12 healthy and 24 T. gallinae-infected pigeons to investigate association between the novel Malacoplasma sp. and T. gallinae. We utilised Illumina metagenomics sequencing targeted to pigeon oral and crop samples infected with the novel Malacoplasma sp. to generate its full-length genome sequence. Sequence similarity network analysis was used to compare annotated proteins from the novel Malacoplasma sp. with a range of other related species.

Results

Here we present evidence for a novel Malacoplasma species, related to "Ca. M. girerdii," that is strongly associated with T. gallinae in the upper digestive tract of domestic pigeons. Analysis of the genome sequence revealed gene features apparently specific to a Trichomonas-symbiotic Malacoplasma lineage.

Discussion

These data support a model of long-term association between Trichomonas and Malacoplasma spp. that has been conserved across diversification of the Trichomonas lineage and the host species barrier from birds to human.

Cervical and Vaginal Microbiomes in Early Miscarriages and Ongoing Pregnancy with and without Dydrogesterone Usage

Emerging evidence suggests that the reproductive tract microbiota is a key modulator of local inflammatory and immune pathways throughout pregnancy and may subsequently impact pregnancy outcomes. In this study, our objective was to analyze the cervical and vaginal microbiomes during early pregnancy among three groups: women with healthy ongoing pregnancies, women undergoing dydrogesterone treatment, and those who experienced miscarriages. The experiment involved 51 women at 8-11 weeks of gestation. The microbiome was examined using 16S rRNA sequencing on the Ion Torrent PGM platform. Across all groups, Lactobacillus iners was predominant, suggesting that the vaginal community type CST III is common among the majority of participants. Notably, our data highlighted the significant roles of Gardnerella vaginalis and Mycoplasma girerdii in the pathogenesis of early miscarriage. Conversely, L. iners and Bifidobacterium longum have a protective effect in early pregnancy. Moreover, dydrogesterone intake appeared to influence notable differences between the cervical and vaginal microbiomes. Overall, our study enhanced our understanding of the cervical and vaginal microbiome composition in the eastern European population during early pregnancy.

Mycoplasma hominis and Candidatus Mycoplasma girerdii in Trichomonas vaginalis: Peaceful Cohabitants or Contentious Roommates?

Trichomonas vaginalis is a pathogenic protozoan diffused worldwide capable of infecting the urogenital tract in humans, causing trichomoniasis. One of its most intriguing aspects is the ability to establish a close relationship with endosymbiotic microorganisms: the unique association of T. vaginalis with the bacterium Mycoplasma hominis represents, to date, the only example of an endosymbiosis involving two true human pathogens. Since its discovery, several aspects of the symbiosis between T. vaginalis and M. hominis have been characterized, demonstrating that the presence of the intracellular guest strongly influences the pathogenic characteristics of the protozoon, making it more aggressive towards host cells and capable of stimulating a stronger proinflammatory response. The recent description of a further symbiont of the protozoon, the newly discovered non-cultivable mycoplasma Candidatus Mycoplasma girerdii, makes the picture even more complex. This review provides an overview of the main aspects of this complex microbial consortium, with particular emphasis on its effect on protozoan pathobiology and on the interplays among the symbionts.

The Prevalence of Genital Mycoplasmas and Coinfection with Trichomonas vaginalis in Female Patients in Vienna, Austria

Trichomonas vaginalis causes trichomoniasis, the most recurrent sexually transmitted infection (STI) worldwide. Genital mycoplasmas, not considered STI agents, are frequently isolated from the female genital tract. A symbiosis between Mycoplasma species and T. vaginalis has been described. The aim of this study was to conduct molecular-based analyses of vaginal specimens, thus assessing the prevalence of non-STI Mycoplasma infections. In total, 582 samples from female patients and an additional 20 T. vaginalis isolates were analyzed by PCR using Mycoplasma specific 16S rRNA primers, and the obtained PCR products were sequenced. Mycoplasma species were detected in 28.2% of the collected vaginal samples. Mycoplasma hominis was found in 21.5% of the specimens, Ureaplasma species were found in 7.5% of the samples. The molecular data of the newly described species, CandidatusMycoplasma girerdii, were obtained for the first time in Austria, in a sample also positive for T. vaginalis. Analyses of the cultivated T. vaginalis strains confirmed the presence of M. hominis in two out of 20 samples. A comparably high prevalence of genital mycoplasmas was revealed through advanced diagnostic assays, with M. hominis and U. parvum being the most prevalent species. The previously described symbiotic relationship between M. hominis and T. vaginalis was confirmed.

Roles of the Microbiota of the Female Reproductive Tract in Gynecological and Reproductive Health

The microbiome of the female reproductive tract defies the convention that high biodiversity is a hallmark of an optimal ecosystem. Although not universally true, a homogeneous vaginal microbiome composed of species of Lactobacillus is generally associated with health, whereas vaginal microbiomes consisting of other taxa are generally associated with dysbiosis and a higher risk of disease. The past decade has seen a rapid advancement in our understanding of these unique biosystems. Of particular interest, substantial effort has been devoted to deciphering how members of the microbiome of the female reproductive tract impact pregnancy, with a focus on adverse outcomes, including but not limited to preterm birth. Herein, we review recent research efforts that are revealing the mechanisms by which these microorganisms of the female reproductive tract influence gynecologic and reproductive health of the female reproductive tract.

Prevalence of selected sexually transmitted infectious agents in a cohort of asymptomatic soldiers in Austria

BACKGROUND

According to the World Health Organization (WHO), more than one million sexually transmitted infections (STIs) are acquired every day worldwide. Although STIs may be asymptomatic in many cases, they can cause severe symptoms and can also lead to adverse pregnancy outcomes and both male and female infertility. Asymptomatic carriers seem to play an important role in terms of the distribution of STIs; however, studies revealing the prevalence of STIs in asymptomatic individuals are rare.

METHODS

In the current study, 654 leftovers of standard urine samples from healthy, asymptomatic Austrian soldiers were investigated for the prevalence of Trichomonas vaginalis, Chlamydia trachomatis, and genital mycoplasmas (Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Ureaplasma parvum, and Candidatus Mycoplasma girerdii) by specific PCRs.

RESULTS

We detected T. vaginalis, M. hominis, U. urealyticum, U. parvum, and C. trachomatis in the investigated samples with prevalence of 7.6%, 4%, 2.4%, 5.4%, and 3.2%, respectively; neither M. genitalium nor Ca. Mycoplasma girerdii was found in our sample collection.

CONCLUSIONS

Our study introduces data on STIs of a mainly male cohort, which are scarce because most of the available information on sexually transmitted infectious agents arises from fertility clinics (mainly women) or symptomatic patients.

Two Different Species of Mycoplasma Endosymbionts Can Influence Trichomonas vaginalis Pathophysiology

Trichomonas vaginalis can host the endosymbiont Mycoplasma hominis, an opportunistic pathogenic bacterium capable of modulating T. vaginalis pathobiology. Recently, a new noncultivable mycoplasma, "Candidatus Mycoplasma girerdii," has been shown to be closely associated with women affected by trichomoniasis, suggesting a biological association. Although several features of "Ca. M. girerdii" have been investigated through genomic analysis, the nature of the potential T. vaginalis-"Ca. M. girerdii" consortium and its impact on the biology and pathogenesis of both microorganisms have not yet been explored. Here, we investigate the association between "Ca. M. girerdii" and T. vaginalis isolated from patients affected by trichomoniasis, demonstrating their intracellular localization. By using an in vitro model system based on single- and double-Mycoplasma infection of Mycoplasma-free isogenic T. vaginalis, we investigated the ability of the protist to establish a relationship with the bacteria and impact T. vaginalis growth. Our data indicate likely competition between M. hominis and "Ca. M. girerdii" while infecting trichomonad cells. Comparative dual-transcriptomics data showed major shifts in parasite gene expression in response to the presence of Mycoplasma, including genes associated with energy metabolism and pathogenesis. Consistent with the transcriptomics data, both parasite-mediated hemolysis and binding to host epithelial cells were significantly upregulated in the presence of either Mycoplasma species. Taken together, these results support a model in which this microbial association could modulate the virulence of T. vaginalis. IMPORTANCE T. vaginalis and M. hominis form a unique case of endosymbiosis that modulates the parasite's pathobiology. Recently, a new nonculturable mycoplasma species ("Candidatus Mycoplasma girerdii") has been described as closely associated with the protozoon. Here, we report the characterization of this endosymbiotic relationship. Clinical isolates of the parasite demonstrate that mycoplasmas are common among trichomoniasis patients. The relationships are studied by devising an in vitro system of single and/or double infections in isogenic protozoan recipients. Comparative growth experiments and transcriptomics data demonstrate that the composition of different microbial consortia influences the growth of the parasite and significantly modulates its transcriptomic profile, including metabolic enzymes and virulence genes such as adhesins and pore-forming proteins. The data on modulation from RNA sequencing (RNA-Seq) correlated closely with those of the cytopathic effect and adhesion to human target cells. We propose the hypothesis that the presence and the quantitative ratios of endosymbionts may contribute to modulating protozoan virulence. Our data highlight the importance of considering pathogenic entities as microbial ecosystems, reinforcing the importance of the development of integrated diagnostic and therapeutic strategies.

Effect of the Symbiosis with Mycoplasma hominis and Candidatus Mycoplasma Girerdii on Trichomonas vaginalis Metronidazole Susceptibility

Trichomoniasis, the most common non-viral sexually transmitted infection worldwide, is caused by the protozoon Trichomonas vaginalis. The 5- nitroimidazole drugs, of which metronidazole is the most prescribed, are the only effective drugs to treat trichomoniasis. Resistance against metronidazole is increasingly reported among T. vaginalis isolates. T. vaginalis can establish an endosymbiosis with two Mycoplasma species, Mycoplasma hominis and Candidatus Mycoplasma girerdii, whose presence has been demonstrated to influence several aspects of the protozoan pathobiology. The role of M. hominis in T. vaginalis resistance to metronidazole is controversial, while the influence of Ca. M. girerdii has never been investigated. In this work, we investigate the possible correlation between the presence of Ca. M. girerdii and/or M. hominis and the in vitro drug susceptibility in a large group of T. vaginalis isolated in Italy and in Vietnam. We also evaluated, via RNA-seq analysis, the expression of protozoan genes involved in metronidazole resistance in a set of syngenic T. vaginalis strains, differing only for the presence/absence of the two Mycoplasmas. Our results show that the presence of M. hominis significantly increases the sensitivity to metronidazole in T. vaginalis and affects gene expression. On the contrary, the symbiosis with Candidatus Mycoplasma girerdii seems to have no effect on metronidazole resistance in T. vaginalis.

High Co-Infection Rate of Trichomonas vaginalis and Candidatus Mycoplasma Girerdii in Gansu Province, China

Trichomonas vaginalis (Tv) is a flagellated protist parasite that infects the human urogenital tract. The symbiotic relationship between Tv and Mycoplasma hominis has been reported. Recent studies have identified a new Mycoplasma strain, Candidatus Mycoplasma girerdii (Ca. M. girerdii), present in the vaginal secretions of women and have shown that this strain may be related to trichomoniasis. Here, we evaluated the presence of Tv, M. hominis and Ca. M. girerdii in 312 clinical samples from adult women diagnosed with vaginitis in Zhangye, Gansu province, China. Among these samples, 94, 153, and 48 were Tv, M. hominis and Ca. M. girerdii positive, respectively. Moreover, Tv was highly frequent in 17–30-year-old women in this region. Forty samples (83.3%) positive for Ca. M. girerdii were also positive for Tv. Six Tv isolates were successfully cultured, including five isolates that showed symbiotic relationships with Mycoplasma. This is the first report to evaluate the genetic characteristics of Ca. M. girerdii in China and may therefore provide insights into the effects of Ca. M. girerdii on the reproductive health of women.

Group B Streptococcus and the vaginal microbiome among pregnant women: a systematic review

BACKGROUND

Vaginal microbiome studies frequently report diversity metrics and communities of microbiomes associated with reproductive health outcomes. Reports of Streptococcus agalactiae (also known as Group B Streptococcus or GBS), the leading cause of neonatal infectious morbidity and mortality, are notably lacking from the studies of the vaginal microbiome, despite being a known contributor to preterm birth and other complications. Therefore, the purpose of this systematic review was to explore the frequency of GBS reporting in vaginal microbiome literature pertaining to pregnancy and to examine methodological bias that contributes to differences in species and genus-level microbiome reporting. Lack of identification of GBS via sequencing-based approaches due to methodologic or reporting bias may result incomplete understanding of bacterial composition during pregnancy and subsequent birth outcomes.

METHODOLOGY

A systematic review was conducted following the PRISMA guideline. Three databases (PubMed, CINAHL, and Web of Science) were used to identify papers for review based on the search terms "vaginal microbiome", "pregnancy", and "16S rRNA sequencing". Articles were evaluated for methods of DNA extraction and sequencing, 16S region, taxonomy classification database, number of participants or vaginal specimens, and pregnancy trimester.

RESULTS

Forty-five research articles reported employing a metagenomic approach or 16S approach for vaginal microbiome analysis during pregnancy that explicitly reported taxonomic composition and were included in this review. Less than 30% of articles reported the presence of GBS (N = 13). No significant differences in methodology were identified between articles that reported versus did not report GBS. However, there was large variability across research methods used for vaginal microbiome analysis and species-level bacterial community reporting.

CONCLUSION

Considerable differences in study design and data formatting methods may contribute to underrepresentation of GBS, and other known pathogens, in existing vaginal microbiome literature. Previous studies have identified considerable variation in methodology across vaginal microbiome studies. This study adds to this body of work because in addition to laboratory or statistical methods, how results and data are shared (e.g., only analyzing genus level data or 20 most abundant microbes), may hinder reproducibility and limit our understanding of the influence of less abundant microbes. Sharing detailed methods, analysis code, and raw data may improve reproducibility and ability to more accurately compare microbial communities across studies.

STROBE-sequencing analysis of the vaginal microecology of 4- to 6-year-old girls in Southwest China

We investigated the vaginal flora diversity of preschool-aged (ie, 4-6-year-old) girls in southwest China.Fourteen preschool-aged girls were enrolled in this study. The statuses and differences in their vaginal flora were evaluated by Gram staining, bacterial culturing, and sequencing analysis.Gram staining and microbial culturing showed that the main vaginal flora of the preschool-aged girls were Gram-negative bacilli, whereas the main vaginal flora of healthy adult controls were large Gram-positive bacilli such as Lactobacillus crispatus. Shannon and Simpson indexes indicated that the bacterial diversity tended to decrease with age. The species abundance heat map showed that the vaginal microecology of the girls differed slightly at different ages but mainly comprised Pseudomonas, Methylobacterium, Sphingomona,s and Escherichia. The functional abundance heat map indicated that the bacterial functions increased with age.The vaginal microecology of preschool-aged girls differs from that of adults. A comprehensive understanding of the vaginal flora diversity of preschool-aged girls will aid in clinically diagnosing vulvovaginitis in preschool-aged girls.

Infection strategies of mycoplasmas: Unraveling the panoply of virulence factors

Mycoplasmas, the smallest bacteria lacking a cell wall, can cause various diseases in both humans and animals. Mycoplasmas harbor a variety of virulence factors that enable them to overcome numerous barriers of entry into the host; using accessory proteins, mycoplasma adhesins can bind to the receptors or extracellular matrix of the host cell. Although the host immune system can eradicate the invading mycoplasma in most cases, a few sagacious mycoplasmas employ a series of invasion and immune escape strategies to ensure their continued survival within their hosts. For instance, capsular polysaccharides are crucial for anti-phagocytosis and immunomodulation. Invasive enzymes degrade reactive oxygen species, neutrophil extracellular traps, and immunoglobulins. Biofilm formation is important for establishing a persistent infection. During proliferation, successfully surviving mycoplasmas generate numerous metabolites, including hydrogen peroxide, ammonia and hydrogen sulfide; or secrete various exotoxins, such as community-acquired respiratory distress syndrome toxin, and hemolysins; and express various pathogenic enzymes, all of which have potent toxic effects on host cells. Furthermore, some inherent components of mycoplasmas, such as lipids, membrane lipoproteins, and even mycoplasma-generated superantigens, can exert a significant pathogenic impact on the host cells or the immune system. In this review, we describe the proposed virulence factors in the toolkit of notorious mycoplasmas to better understand the pathogenic features of these bacteria, along with their pathogenic mechanisms.

Recent advances in the molecular biology of the protist parasite Trichomonas vaginalis

Trichomonas vaginalis is an anaerobic/microaerophilic protist parasite which causes trichomoniasis, one of the most prevalent sexually transmitted diseases worldwide. T. vaginalis not only is important as a human pathogen but also is of great biological interest because of its peculiar cell biology and metabolism, in earlier times fostering the erroneous notion that this microorganism is at the root of eukaryotic evolution. This review summarizes the major advances in the last five years in the T. vaginalis field with regard to genetics, molecular biology, ecology, and pathogenicity of the parasite.

Paradigms of Protist/Bacteria Symbioses Affecting Human Health: Acanthamoeba species and Trichomonas vaginalis

Ever since the publication of the seminal paper by Lynn Margulis in 1967 proposing the theory of the endosymbiotic origin of organelles, the study of the symbiotic relationships between unicellular eukaryotes and prokaryotes has received ever-growing attention by microbiologists and evolutionists alike. While the evolutionary significance of the endosymbiotic associations within protists has emerged and is intensively studied, the impact of these relationships on human health has been seldom taken into account. Microbial endosymbioses involving human eukaryotic pathogens are not common, and the sexually transmitted obligate parasite Trichomonas vaginalis and the free-living opportunistic pathogen Acanthamoeba represent two unique cases in this regard, to date. The reasons of this peculiarity for T. vaginalis and Acanthamoeba may be due to their lifestyles, characterized by bacteria-rich environments. However, this characteristic does not fully explain the reason why no bacterial endosymbiont has yet been detected in unicellular eukaryotic human pathogens other than in T. vaginalis and Acanthamoeba, albeit sparse and poorly investigated examples of morphological identification of bacteria-like microorganisms associated with Giardia and Entamoeba were reported in the past. In this review article we will present the body of experimental evidences revealing the profound effects of these examples of protist/bacteria symbiosis on the pathogenesis of the microbial species involved, and ultimately their impact on human health.

Lists of names of prokaryotic Candidatus taxa

We here present annotated lists of names of Candidatus taxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status of Candidatus taxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names of Candidatus taxa with additions and corrections to the current lists to be published periodically in the International Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of the Candidatus names if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.

Specific Vaginal Bacteria Are Associated With an Increased Risk of Trichomonas vaginalis Acquisition in Women

BACKGROUND

While bacterial vaginosis has been associated with an increased risk of Trichomonas vaginalis (TV) acquisition, it is unknown whether other characteristics of the vaginal microbiota, including the presence of key bacterial species, influence a woman's risk of TV acquisition.

METHODS

The vaginal microbiota before 25 unique episodes of TV infection involving 18 women was compared to that of 50 controls who remained uninfected. TV was detected by transcription-mediated amplification. Vaginal microbiota were quantified using broad-range polymerase chain reaction analysis and taxon-specific quantitative PCR of the 16S ribosomal RNA gene.

RESULTS

TV acquisition was significantly associated with the presence of Prevotella amnii (risk ratio [RR], 2.21; 95% confidence interval [CI], 1.12-4.38; P = .02) and Sneathia sanguinegens (RR, 2.58; 95% CI, 1.00-6.62; P = .049). When adjusted for menstrual phase, the association between P. amnii and TV acquisition remained similar (adjusted RR, 2.11; 95% CI, 1.03-4.33; P = .04), but the association between S. sanguinegens and TV acquisition was attenuated (adjusted RR, 2.31; 95% CI, .86-6.23; P = .10).

CONCLUSIONS

Key vaginal bacterial species may contribute to the susceptibility to TV acquisition. Understanding how these bacterial species increase a woman's risk of TV acquisition could help to guide the development of novel strategies to reduce women's risk of TV infection.

Impact of Symbiosis Between Trichomonas vaginalis and Mycoplasma hominis on Vaginal Dysbiosis: A Mini Review

The protozoon Trichomonas vaginalis is responsible for trichomoniasis, a common sexually transmitted infection associated with an increased risk of HIV infection and adverse pregnancy outcomes. The protozoon has the surprising ability to establish a symbiotic relationship with other microorganisms. In fact, most T.vaginalis isolates intracellularly host the vaginal bacterium Mycoplasma hominis and can harbor up to four dsRNA viruses. Moreover, a novel Mycoplasma species named Ca. Mycoplasma girerdii has been recently described as associated with trichomonad cells. Trichomonas vaginalis colonizes the human vagina and its presence causes profound alterations of the resident microbiota, leading to dysbiosis. In healthy women, vaginal microbiota is characterized by the presence of a complex population of aerobic and anaerobic microorganisms living in a physiologically dynamic system dominated by bacteria of the genera Lactobacillus. The most common microbial vaginal imbalance is bacterial vaginosis, a polymicrobial disease associated with several adverse reproductive outcomes and increased risk of HIV infection. Here, we review the current knowledge regarding the interactions between both T.vaginalis and M.hominis and the vaginal microbiota, and we discuss the possibility of a cooperation between T.vaginalis and its symbionts in the development of vaginal dysbiosis.

Microbiota in vaginal health and pathogenesis of recurrent vulvovaginal infections: a critical review

Recurrent vulvovaginal infections (RVVI) has not only become an epidemiological and clinical problem but also include large social and psychological consequences. Understanding the mechanisms of both commensalism and pathogenesis are necessary for the development of efficient diagnosis and treatment strategies for these enigmatic vaginal infections. Through this review, an attempt has been made to analyze vaginal microbiota (VMB) from scratch and to provide an update on its current understanding in relation to health and common RVVI i.e. bacterial vaginosis, vulvovaginal candidiaisis and Trichomoniasis, making the present review first of its kind. For this, potentially relevant studies were retrieved from data sources and critical analysis of the literature was made. Though, culture-independent methods have greatly unfolded the mystery regarding vaginal bacterial microbiome, there are only a few studies regarding the composition and diversity of vaginal mycobiome and different Trichomonas vaginalis strains. This scenario suggests a need of further studies based on comparative genomics of RVVI pathogens to improve our perceptive of RVVI pathogenesis that is still not clear (Fig. 5). Besides this, the review details the rationale for Lactobacilli dominance and changes that occur in healthy VMB throughout a women's life. Moreover, the list of possible agents continues to expand and new species recognised in both health and VVI are updated in this review. The review concludes with the controversies challenging the widely accepted dogma i.e. "VMB dominated with Lactobacilli is healthier than a diverse VMB". These controversies, over the past decade, have complicated the definition of vaginal health and vaginal infections with no definite conclusion. Thus, further studies on newly recognised microbial agents may reveal answers to these controversies. Conversely, VMB of women could be an answer but it is not enough to just look at the microbiology. We have to look at the woman itself, as VMB which is fine for one woman may be troublesome for others. These differences in women's response to the same VMB may be determined by a permutation of behavioural, cultural, genetic and various other anonymous factors, exploration of which may lead to proper definition of vaginal health and disease.

Understanding and interpreting community sequencing measurements of the vaginal microbiome

Community-wide high-throughput sequencing has transformed the study of the vaginal microbiome, and clinical applications are on the horizon. Here we outline the three main community sequencing methods: (1) amplicon sequencing, (2) shotgun metagenomic sequencing, and (3) metatranscriptomic sequencing. We discuss the advantages and limitations of community sequencing generally, and the unique strengths and weaknesses of each method. We briefly review the contributions of community sequencing to vaginal microbiome research and practice. We develop suggestions for critically interpreting research results and potential clinical applications based on community sequencing of the vaginal microbiome. TWEETABLE ABSTRACT: We review the advantages and limitations of amplicon sequencing, metagenomics, and metatranscriptomics methods for the study of the vaginal microbiome.

High Prevalence of Integrative and Conjugative Elements Encoding Transcription Activator-Like Effector Repeats in Mycoplasma hominis

Integrative and conjugative elements (ICEs) are modular mobile genetic elements that can disseminate through excision, circularization, and transfer. Mycoplasma ICEs have recently been found distributed among some mycoplasma species and there is accumulating evidence that they play a pivotal role in horizontal gene transfers. The occurrence of ICEs has not been documented in Mycoplasma hominis, a human urogenital pathogen responsible for urogenital infections, neonatal infections and extragenital infections. In this study, we searched for, characterized, and compared ICEs by genome analyses of 12 strains of M. hominis. ICEs of 27–30 kb were found in one or two copies in seven of the 12 M. hominis strains sequenced. Only five of these ICEs seemed to be functional, as assessed by detection of circular forms of extrachromosomal ICE. Moreover, the prevalence of ICEs in M. hominis was estimated to be 45% in a collection of 120 clinical isolates of M. hominis, including 27 tetracycline-resistant tet(M)-positive isolates. The proportion of ICEs was not higher in isolates carrying the tet(M) gene, suggesting that ICEs are not involved in tetracycline resistance. Notably, all M. hominis ICEs had a very similar structure, consisting of a 4.0–5.1 kb unusual module composed of five to six juxtaposed CDSs. All the genes forming this module were specific to M. hominis ICEs as they had no homologs in other mycoplasma ICEs. In each M. hominis ICE, one to three CDSs encode proteins that share common structural features with transcription activator-like (TAL) effectors involved in polynucleotide recognition and signal transduction in symbiotic plant pathogen bacteria. The conserved and specific structure of M. hominis ICEs and the high prevalence in clinical strains suggest that these ICEs may confer a selective advantage for the physiology or pathogenicity of this human pathogenic bacterium. These data open the way for further studies aiming at unraveling horizontal gene transfers and virulence factors in M. hominis.

Trichomonas vaginalis and Mycoplasma infections among women with vaginal discharge at Fann teaching hospital in Senegal

Background:

Trichomonas vaginalis and genital Mycoplasmas are two synergistic pathogens, but in many settings, limited data on the co-infection by Trichomonas and Mycoplasma are available.

Objective:

This study aimed at assessing Mycoplasma prevalence and its association with Trichomonas vaginalis among women with vaginal discharge.

Materials and Methods:

A retrospective analysis of laboratory records (2012 and 2013) from patients referred at the Fann teaching hospital in Dakar Senegal for vaginal discharge was carried out. Detection of genital mycoplasmas was based on the commercial Kit Mycoplasma Duo Bio-Rad™ using endo-cervical swabs. Vaginal swabs were collected and examined using optic microscopy with 40x magnification to detect T. vaginalis.

Results:

Overall, data from 1257 women were analysed. Prevalence of Mycoplasma hominis represented 57.4%, 95%CI(54.6-60.1), versus 54.9%, 95%CI(52.1-57.5) for Ureaplasma urealyticum. Trichomonas vaginalis infection was observed with a frequency of 3%. Out of the 50 patients with trichomoniasis, 76% of them were co-infected by Mycoplasma hominis and patients with Trichomonas vaginalis had an increased risk of acquiring Mycoplasma infection (adjusted OR:2.5, 95%CI(1.2-5.2);p=0.02)).

Conclusion:

Trichomonas vaginalis and Mycoplasmas are two closely associated pathogens in the urogenital tract of women. This clinically significant symbiotic action may require systematic screening of Mycoplasma among patients with trichomoniasis for optimal management of sexually transmitted infections.

Mollicutes antibiotic resistance profile and presence of genital abnormalities in couples attending an infertility clinic

Objective

Methods

Results

Conclusion

Trichomonas vaginalis and Mycoplasma hominis: new tales of two old friends

Trichomonas vaginalis is an anaerobic protist, responsible for the most prevalent non-viral sexually transmitted infection in humans. One of the most intriguing aspects of T. vaginalis pathobiology is the complex relationship with intracellular microbial symbionts: a group of dsRNA viruses belonging to family of Totiviridae (T. vaginalis virus), and eubacteria belonging to the Mycoplasma genus, in particular Mycoplasma hominis. Both microorganisms seem to strongly influence the lifestyle of T. vaginalis, suggesting a role of the symbiosis in the high variability of clinical presentation and sequelae during trichomoniasis. In the last few years many aspects of this unique symbiotic relationship have been investigated: M. hominis resides and replicates in the protozoan cell, and T. vaginalis is able to pass the bacterial infection to both mycoplasma-free protozoan isolates and human epithelial cells; M. hominis synergistically upregulates the proinflammatory response of human monocytes to T. vaginalis. Furthermore, the influence of M. hominis over T. vaginalis metabolism and physiology has been characterized. The identification of a novel species belonging to the class of Mollicutes (Candidatus Mycoplasma girerdii) exclusively associated to T. vaginalis opens new perspectives in the research of the complex series of events taking place in the multifaceted world of the vaginal microbiota, both under normal and pathological conditions.

Urogenital pathogens, associated with Trichomonas vaginalis, among pregnant women in Kilifi, Kenya: a nested case-control study

Background

Screening of curable sexually transmitted infections is frequently oriented towards the diagnosis of chlamydia, gonorrhea, syphilis and trichomoniasis, whereas other pathogens, sometimes associated with similar urogenital syndromes, remain undiagnosed and/or untreated. Some of these pathogens are associated with adverse pregnancy outcomes.

Methods

In a nested case-control study, vaginal swabs from 79 pregnant women, i.e., 28 T. vaginalis-positive (cases) and 51 T. vaginalis-negative (controls), were screened by quantitative PCR for Adenovirus 1 and 2, Cytomegalovirus, Herpes Simplex Virus 1 and 2, Chlamydia trachomatis, Escherichia coli, Haemophilus ducreyi, Mycoplasma genitalium, M. hominis, candidatus M. girerdii, Neisseria gonorrhoeae, Streptococcus agalactiae, Treponema pallidum, Ureaplasma parvum, U. urealyticum, and Candida albicans. Additionally, we determined whether women with pathogens highly associated with T. vaginalis had distinct clinical signs and symptoms compared to women with T. vaginalis mono-infection.

Results

M. hominis was independently associated with T. vaginalis (adjusted odds ratio = 6.8, 95% CI: 2.3–19.8). Moreover, M. genitalium and Ca M. girerdii were exclusively detected in women with T. vaginalis (P = 0.002 and P = 0.001), respectively. Four of the six women co-infected with T. vaginalis and Ca M. girerdii complained of vaginal itching, compared to only 4 out of the 22 women infected with T. vaginalis without Ca M. girerdii (P = 0.020).

Conclusion

We confirm M. hominis as a correlate of T. vaginalis in our population, and the exclusive association of both M. genitalium and Ca. M. girerdii with T. vaginalis. Screening and treatment of these pathogens should be considered.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3455-4) contains supplementary material, which is available to authorized users.

The two-sided role of the vaginal microbiome in Chlamydia trachomatis and Mycoplasma genitalium pathogenesis

Sexually transmitted infections (STI) can have major consequences for the reproductive health of women. Mycoplasma genitalium is a STI that is not as well studied but causes pelvic inflammatory disease (PID) among other complications. Another well-known STI is Chlamydia trachomatis, notorious for its capability to cause infertility. Both C. trachomatis and M. genitalium share some of the same clinical aspects. Parts of the pathogenesis of C. trachomatis and M. genitalium infections are unclear but potential factors are the microbiome and other STIs. The healthy vaginal microbiome is dominated by Lactobacillus spp; these bacteria protect the host against invading bacteria like C. trachomatis and M. genitalium by producing antibacterial compounds and providing a mechanical barrier. A dysbiosis of the vaginal microbiome is characterized by a non-Lactobacillus spp. dominated microbiome, also known as bacterial vaginosis (BV). BV and BV associated bacteria play a role in the pathogenesis of STIs such as C. trachomatis and M. genitalium. The different species of BV associated bacteria have distinct characteristics that could play a role in C. trachomatis and M. genitalium infections. Host factors should also be considered when analysing the interaction of C. trachomatis and M. genitalium and the microbiome. One important factor is the hormonal homeostasis. Oral hormonal contraception influences the vaginal milieu and could influence the infection process of STIs. Overall, this review attempts to give an overview of the pathogenesisof C. trachomatis and M. genitalium infections and the relationship between M. genitalium, C. trachomatis, and the vaginal microbiome.

Trichomonas vaginalis: Pathogenesis, Symbiont Interactions, and Host Cell Immune Responses

The parasite Trichomonas vaginalis (Tv) causes a highly prevalent sexually transmitted infection. As an extracellular pathogen, the parasite mediates adherence to epithelial cells to colonize the human host. In addition, the parasite interfaces with the host immune system and the vaginal microbiota. Modes of Tv pathogenesis include damage to host tissue mediated by parasite killing of host cells, disruption of steady-state vaginal microbial ecology, and eliciting inflammation by activating the host immune response. Recent Tv research has uncovered new players that contribute to multifactorial mechanisms of host-parasite adherence and killing, and has examined the relationship between Tv and vaginal bacteria. Mechanisms that may lead to parasite recognition and killing, or the evasion of host immune cells, have also been revealed.

Phylogenetic framework for the phylum Tenericutes based on genome sequence data: proposal for the creation of a new order Mycoplasmoidales ord. nov., containing two new families Mycoplasmoidaceae fam. nov. and Metamycoplasmataceae fam. nov. harbouring Eperythrozoon, Ureaplasma and five novel genera

The genus Mycoplasma, including species earlier classified in the genera Eperythrozoon and Haemobartonella, contains ~ 120 species and constitutes an extensively polyphyletic assemblage of bacteria within the phylum Tenericutes. Due to their small genome sizes and lack of unique characteristics, the relationships among the mycoplasmas/Tenericutes are not reliably discerned. Using genome sequences for 140 Tenericutes, their evolutionary relationships were examined using multiple independent approaches. Phylogenomic trees were constructed for 63 conserved proteins, 45 ribosomal proteins, three main subunits of RNA polymerase and 16S rRNA gene sequences. In all of these trees, Tenericutes species reliably grouped into four main clades designated as the "Acholeplasma", "Spiroplasma", "Pneumoniae" and "Hominis" clusters. These clades are also distinguished based on a similarity matrix constructed based on 16S rRNA gene sequences. Mycoplasma species were dispersed across 3 of these 4 clades highlighting their extensive polyphyly. In parallel, our comparative genomic analyses have identified > 100 conserved signature indels (CSIs) and 14 conserved signature proteins (CSPs), which are uniquely shared by the members of four identified clades, strongly supporting their monophyly and identifying them in molecular terms. Mycoplasma mycoides, the type species of the genus Mycoplasma, and a small number of other Mycoplasma species, formed a strongly supported clade within the "Spiroplasma" cluster. Nine CSIs and 14 CSPs reliably distinguish this clade from all other Mycoplasmatales species. The remainder of the Mycoplasmatales species are part of the "Pneumoniae" and "Hominis" clusters, which group together in phylogenetic trees. Here we are proposing that the order Mycoplasmatales should be emended to encompass only the Mycoplasma species within the "Spiroplasma" cluster and that a new order, Mycoplasmoidales ord. nov., should be created to encompass the other Mycoplasma species. The "Pneumoniae" and the "Hominis" clusters are proposed as two new families, Mycoplasmoidaceae fam. nov., which includes the genera Eperythrozoon, Ureaplasma, and the newly proposed genera Malacoplasma and Mycoplasmoides, and Metamycoplasmataceae fam. nov. to contain the newly proposed genera Metamycoplasma, Mycoplasmopsis, and Mesomycoplasma. The results presented here allow reliable discernment, both in phylogenetic and molecular terms, of the members of the two proposed families as well as different described genera within these families including members of the genus Eperythrozoon, which is comprised of uncultivable organisms. The taxonomic reclassifications proposed here, which more accurately portray the genetic diversity among the Tenericutes/Mycoplasma species, provide a new framework for understanding the biological and clinical aspects of these important microbes.

Replication and refinement of a vaginal microbial signature of preterm birth in two racially distinct cohorts of US women

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality. Previous studies have suggested that the maternal vaginal microbiota contributes to the pathophysiology of PTB, but conflicting results in recent years have raised doubts. We conducted a study of PTB compared with term birth in two cohorts of pregnant women: one predominantly Caucasian (n = 39) at low risk for PTB, the second predominantly African American and at high-risk (n = 96). We profiled the taxonomic composition of 2,179 vaginal swabs collected prospectively and weekly during gestation using 16S rRNA gene sequencing. Previously proposed associations between PTB and lower Lactobacillus and higher Gardnerella abundances replicated in the low-risk cohort, but not in the high-risk cohort. High-resolution bioinformatics enabled taxonomic assignment to the species and subspecies levels, revealing that Lactobacillus crispatus was associated with low risk of PTB in both cohorts, while Lactobacillus iners was not, and that a subspecies clade of Gardnerella vaginalis explained the genus association with PTB. Patterns of cooccurrence between L. crispatus and Gardnerella were highly exclusive, while Gardnerella and L. iners often coexisted at high frequencies. We argue that the vaginal microbiota is better represented by the quantitative frequencies of these key taxa than by classifying communities into five community state types. Our findings extend and corroborate the association between the vaginal microbiota and PTB, demonstrate the benefits of high-resolution statistical bioinformatics in clinical microbiome studies, and suggest that previous conflicting results may reflect the different risk profile of women of black race.

Eve's garden: myths, legends and secrets unmasked

This special issue of Research in Microbiology aims to provide some insights in one of women's most fascinating interacting microbial communities: the vaginal microbiome. Even in the 21st century, with many advanced methods at hand, the definition of the healthy vaginal microbiome remains under debate. The interest in studying the dysbiosis of the vaginal microbiome is increasing and goes well beyond the study of bacterial vaginosis. The selection of contributions in this issue summarizes what is currently known in terms of inter- and intra-microorganisms interaction as well as the virulence factors that some of them may deploy.

Detecting the Diversity of Mycoplasma and Ureaplasma Endosymbionts Hosted by Trichomonas vaginalis Isolates

Objectives: The symbiosis of Trichomonas vaginalis and Mycoplasma hominis is the first described association between two obligate human parasites. Trichomonas is the niche and the vector for the transmission of M. hominis infection. This clinically significant symbiosis may affect T. vaginalis virulence and susceptibility to treatment. The aims of this study were to investigate the intracellularly present Mycoplasma and Ureaplasma species in T. vaginalis strains isolated from the vaginal discharge of infected women as well as to trace the diversity pattern among the species detected in the isolated strains. Methods: Hundred pure T. vaginalis cultures were isolated from ~7,500 patient specimens presented with clinical purulent vaginitis. PCR and sequencing for Mycoplasma/Ureaplasma spp. were performed in DNA extracted from the pure cultures. In addition, vaginal discharge samples were cultured for the presence of M. hominis and U. urealyticum. Phylogenetic analysis assisted the identification of interspecies relationships between the Mycoplasma and Ureaplasma isolates. Results: Fifty four percentage of T. vaginalis isolates were harboring Mycoplasma spp. Phylogenetic analysis revealed three distinct clusters, two with already characterized M. hominis and Ureaplasma spp. (37% of total Mycoplasma spp.), whereas one group formed a distinct cluster matched with the newly identified species Candidatus Mycoplasma girerdii (59.3%) and one or more unknown Mycoplasma spp. (3.7%). Conclusions:T. vaginalis strains associated with vaginal infection might host intracellular mycoplasmas or ureaplasmas. Intracellular Mollicutes that remain undetected in the extracellular environment when conventional diagnostic methods are implemented may comprise either novel species, such as Candidatus M. giredii, or unknown species with yet unexplored clinical significance.

Candidatus Mycoplasma girerdii replicates, diversifies, and co-occurs with Trichomonas vaginalis in the oral cavity of a premature infant

Genital mycoplasmas, which can be vertically transmitted, have been implicated in preterm birth, neonatal infections, and chronic lung disease of prematurity. Our prior work uncovered 16S rRNA genes belonging to a novel, as-yet-uncultivated mycoplasma (lineage ‘Mnola’) in the oral cavity of a premature neonate. Here, we characterize the organism’s associated community, growth status, metabolic potential, and population diversity. Sequencing of genomic DNA from the infant’s saliva yielded 1.44 Gbp of high-quality, non-human read data, from which we recovered three essentially complete (including ‘Mnola’) and three partial draft genomes (including Trichomonas vaginalis). The completed 629,409-bp ‘Mnola’ genome (Candidatus Mycoplasma girerdii str. UC-B3) was distinct at the strain level from its closest relative, vaginally-derived Ca. M. girerdii str. VCU-M1, which is also associated with T. vaginalis. Replication rate measurements indicated growth of str. UC-B3 within the infant. Genes encoding surface-associated proteins and restriction-modification systems were especially diverse within and between strains. In UC-B3, the population genetic underpinnings of phase variable expression were evident in vivo. Unique among mycoplasmas, Ca. M. girerdii encodes pyruvate-ferredoxin oxidoreductase and may be sensitive to metronidazole. This study reveals a metabolically unique mycoplasma colonizing a premature neonate, and establishes the value of genome-resolved metagenomics in tracking phase variation.

Trichomonas vaginalis infection in symbiosis with Trichomonasvirus and Mycoplasma

Trichomonas vaginalis is a protozoan with an extracellular obligatory parasitic lifestyle exclusively adapted to the human urogenital tract and responsible for nearly a quarter billion sexually transmitted infections worldwide each year. This review focuses on symbiotic Trichomonasvirus and mycoplasmas carried by the protozoan, their molecular features and their role in altering the human vaginal microbiome and the immunopathogenicity of the parasite. Improved diagnostics and larger clinical interventional studies are needed to confirm the causative role of protozoan symbionts in the variable clinical presentation of trichomoniasis and its morbid sequelae, including adverse reproductive outcome, susceptibility to viral infections and cancer.

Clinical laboratory assessments for Mycoplasma genitalium in a high-prevalence sexually-transmitted infection community reveal epidemiologic dichotomies with Trichomonas vaginalis

INTRODUCTION

Mycoplasma genitalium is an emerging agent of sexually-transmitted infection and is responsible for clinically-significant genital tract disease in both females and males. Similar to scenarios recently experienced with the urogenital flagellate Trichomonas vaginalis, an evolving molecular diagnostic reference standard based on transcription-mediated amplification allows for accurate detection of the organism, plus additional insight into disease epidemiology. Areas covered. The basis for this article includes primary peer-reviewed literature plus compilations of data derived from routine clinical laboratory screening of females and males for agents of sexually-transmitted infection. Introductory laboratory and epidemiologic data related to T. vaginalis provides not only a foreshadowing to the dichotomies inherent to M. genitalium prevalence but also advocacy of a common non-invasive specimen source that could be used to screen females for both agents. This review also documents increased prevalence rates of M. genitalium in both females and males by way of transcription-mediated amplification. Expert commentary. Molecular detection of M. genitalium should be a consideration in the development of comprehensive sexually-transmitted infection screening programs for both females and males. Transcription-mediated amplification has additionally identified novel facets of M. genitalium and T. vaginalis epidemiology that warrant further investigation.

Leukocyte Lysis and Cytokine Induction by the Human Sexually Transmitted Parasite Trichomonas vaginalis

Trichomonas vaginalis (Tv) is an extracellular protozoan parasite that causes the most common non-viral sexually transmitted infection: trichomoniasis. While acute symptoms in women may include vaginitis, infections are often asymptomatic, but can persist and are associated with medical complications including increased HIV susceptibility, infertility, pre-term labor, and higher incidence of cervical cancer. Heightened inflammation resulting from Tv infection could account for these complications. Effective cellular immune responses to Tv have not been characterized, and re-infection is common, suggesting a dysfunctional adaptive immune response. Using primary human leukocyte components, we have established an in vitro co-culture system to assess the interaction between Tv and the cells of the human immune system. We determined that in vitro, Tv is able to lyse T-cells and B-cells, showing a preference for B-cells. We also found that Tv lysis of lymphocytes was mediated by contact-dependent and soluble factors. Tv lysis of monocytes is far less efficient, and almost entirely contact-dependent. Interestingly, a common symbiont of Tv, Mycoplasma hominis, did not affect cytolytic activity of the parasite, but had a major impact on cytokine responses. M. hominis enabled more diverse inflammatory cytokine secretion in response to Tv and, of the cytokines tested, Tv strains cleared of M. hominis induced only IL-8 secretion from monocytes. The quality of the adaptive immune response to Tv is therefore likely influenced by Tv symbionts, commensals, and concomitant infections, and may be further complicated by direct parasite lysis of effector immune cells.

Symbiotic Association with Mycoplasma hominis Can Influence Growth Rate, ATP Production, Cytolysis and Inflammatory Response of Trichomonas vaginalis

The symbiosis between the parasitic protist Trichomonas vaginalis and the opportunistic bacterium Mycoplasma hominis is the only one currently described involving two obligate human mucosal symbionts with pathogenic capabilities that can cause independent diseases in the same anatomical site: the lower urogenital tract. Although several aspects of this intriguing microbial partnership have been investigated, many questions on the influence of this symbiosis on the parasite pathobiology still remain unanswered. Here, we examined with in vitro cultures how M. hominis could influence the pathobiology of T. vaginalis by investigating the influence of M. hominis on parasite replication rate, haemolytic activity and ATP production. By comparing isogenic mycoplasma-free T. vaginalis and parasites stably associated with M. hominis we could demonstrate that the latter show a higher replication rate, increased haemolytic activity and are able to produce larger amounts of ATP. In addition, we demonstrated in a T. vaginalis-macrophage co-culture system that M. hominis could modulate an aspect of the innate immuno-response to T. vaginalis infections by influencing the production of nitric oxide (NO) by human macrophages, with the parasite-bacteria symbiosis outcompeting the human cells for the key substrate arginine. These results support a model in which the symbiosis between T. vaginalis and M. hominis influences host-microbes interactions to the benefit of both microbial partners during infections and to the detriment of their host.

Prevalence of 7 sexually transmitted organisms by multiplex real-time PCR in Fallopian tube specimens collected from Saudi women with and without ectopic pregnancy

Background

Ectopic pregnancy (EP) is associated with maternal morbidity and occasionally mortality during the first trimester. A history of sexually transmitted infection (STI) and pelvic inflammatory disease have been implicated as major risk factors for EP. Our aim was to measure the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae, Mycoplasma genitalium (MG), Ureaplasma parvum/urealyticum, Gardnerella vaginalis, Trichomonas vaginalis and herpes simplex virus (HSV)-1&2 in Fallopian tubes collected from EP and the results were compared with those obtained from total abdominal hysterectomy (TAH) and tubal ligation.

Methods

This was a prospective case–control study and tubal samples were collected from 135 Saudi women recruited from 3 centres in the Western region as follow: 84 EPs, 20 TAH and 31 tubal ligations. Multiplex TaqMan PCR was performed using an IVD CE kit for the simultaneous detection of candidate pathogens following DNA extraction.

Results

Infections were detected in 31.8 % of the 135 participants either as single (11.1 %) or co-infections (20.7 %) and the frequencies were significantly higher in EP (42.85 %) compared with control (13.72 %). The rates of CT (27.4 %; P = 0.001); MG (20.2 %; P = 0.009) and HSV-1/2 (21.4 %; P = 0.01) were significantly higher in EP. No significant difference between the study groups was observed for the other pathogens (P > 0.05). Binary logistic regression also showed that infection with ≥ 2 pathogens (OR 4.9; 95 % CI: 2.2 – 11.6; P = 0.006), CT (OR 3.07; 95 % CI: 1.3 – 12.3; P = 0.002), MG (OR 2.3; 95 % CI: 1.1 – 8.6; P = 0.03) and HSV-1/2 (OR 1.7; 95 % CI: 0.75 – 5.7; P = 0.004) were associated with a significantly higher risk of developing EP.

Conclusions

STIs are frequent in the upper genital tract of Saudi women during the reproductive age and, CT, MG and HSV-1/2 were more prevalent in EP. The observed high rates of co-infection advocate the necessity of establishing national guidelines and/or screening program utilising multiplex PCR approach for the detection of common STIs among high risk groups in the kingdom. Further studies are needed to measure the adverse reproductive outcomes associated with STIs in Saudi Arabia.

Trichomonas vaginalis origins, molecular pathobiology and clinical considerations

PURPOSE OF REVIEW

To integrate a selection of the most recent data on Trichomonas vaginalis origins, molecular cell biology and T. vaginalis interactions with the urogenital tract microbiota with trichomoniasis symptoms and clinical management.

RECENT FINDINGS

Transcriptomics and proteomics datasets are accumulating, facilitating the identification and prioritization of key target genes to study T. vaginalis pathobiology. Proteins involved in host sensing and cytoskeletal plasticity during T. vaginalis amoeboid transformation were identified. T. vaginalis was shown to secrete exosomes and a macrophage migration inhibitory factor-like protein that both influence host-parasite interactions. T. vaginalis co-infections with Mycoplasma species and viruses were shown to modulate the inflammatory responses, whereas T. vaginalis interactions with various Lactobacillus species inhibit parasite interactions with human cells. T. vaginalis infections were also shown to be associated with bacterial vaginosis. A broader range of health sequelae is also becoming apparent. Diagnostics for both women and men based on the molecular approaches are being refined, in particular for men.

SUMMARY

New developments in the molecular and cellular basis of T. vaginalis pathobiology combined with data on the urogenital tract microbiota and immunology have enriched our knowledge on human-microbe interactions that will contribute to increasing our capacity to prevent and treat T. vaginalis and other sexually transmitted infections.

Trichomonas vaginalis: a review of epidemiologic, clinical and treatment issues

Trichomonas vaginalis (TV) is likely the most common non-viral sexually transmitted infection (STI) in the world. It is as an important source of reproductive morbidity, a facilitator of HIV transmission and acquisition, and thus it is an important public health problem. Despite its importance in human reproductive health and HIV transmission, it is not a reportable disease and surveillance is not generally done. This is problematic since most persons infected with TV are asymptomatic. Metronidazole (MTZ) has been the treatment of choice for women for decades, and single dose has been considered the first line of therapy. However, high rates of retest positive are found among TV infected persons after single dose MTZ treatment. This has not been explained by drug resistance since in vitro resistance is only 2-5 %. Treatment failure can range from 7-10 % and even higher among HIV+ women. Treatment efficacy may be influenced by vaginal ecology. The origins of repeat positives need further explanation and better treatment options are needed.

Synthetic siRNAs effectively target cystein protease 12 and α-actinin transcripts in Trichomonas vaginalis

The flagellated protozoan Trichomonas vaginalis (T. vaginalis) causes trichomoniasis, a reproductive tract infection, in humans. Trichomoniasis is the most common non-viral sexually transmitted disease worldwide. In addition to direct consequences such as infertility and abortion, there are indications that trichomoniasis favours development of prostate cancer and it has also been associated with increased risk of spreading human immunodeficiency virus and papillomavirus infections. Reports from around the world show that the rate of drug resistance in T. vaginalis is increasing, and therefore new therapeutic approaches have to be developed. Studying molecular biology of T. vaginalis will be quite helpful in identifying new drugable targets. RNAi is a powerful technique which allows biologist to specifically target gene products (i.e. mRNA) helping them in unravelling gene functions and biology of systems. However, due to lack of some parts of the required intrinsic RNAi machinery, the RNAi system is not functional in all orders of life. Here, by using synthetic siRNAs targeting two genes, i.e. α-actinin and cystein protease 12 (cp12), we demonstrate T. vaginalis cells are amenable to RNAi experiments conducted by extrinsic siRNAs. Electroporation of siRNAs targeting α-actinin or cp12 into T. vaginalis cells resulted in, respectively, 48-67% and 33-72% downregulation of the cognate transcripts compared to the T. vaginalis cells received siRNAs targeting GL2 luciferase as a control. This finding is helpful in that it demonstrates the potential of using extrinsically induced RNAi in studies on molecular biology of T. vaginalis such as those aiming at identifying new drug targets.