Arginine metabolism in Trichomonas vaginalis infected with Mycoplasma hominis

Patterns of antibiotic resistance of Mycoplasma hominis endosymbiont of Trichomonas vaginalis and the influence of bacterial intracellular location on drug susceptibility

OBJECTIVES

Mycoplasma hominis, an opportunistic pathogen of the human lower urogenital tract, can survive and replicate within the protozoan Trichomonas vaginalis, establishing an endosymbiotic relationship. The intracellular location may provide a means for the bacteria to evade the immune system and protection from antimicrobial activities. Our aim was to investigate the influence of the endosymbiotic association of M. hominis with trichomonad cells on bacterial antibiotic susceptibility.

METHODS

We evaluated antibiotic resistance patterns in a group of M. hominis isolated from T. vaginalis clinical specimens as well as in M. hominis isolated from patients without trichomoniasis. Using an experimental model system, we compared the minimum inhibitory concentration (MIC) and lethal concentration (MLC) of tetracycline on M. hominis endosymbionts of T. vaginalis and extracellular bacteria.

RESULTS

The incidence rate of M. hominis strains resistant to C14 and C15 macrolide antibiotics was higher in intracellular strains associated with T. vaginalis compared with extracellular bacteria isolated from women not affected by trichomoniasis. However, sensitivity to tetracycline and quinolones was similar in both groups. In vitro experiments demonstrated that M. hominis strains, when isolated as endosymbionts from T. vaginalis, exhibited reduced sensitivity to tetracycline when cultured extracellularly for at least eight weeks.

CONCLUSION

The intracellular localization of bacteria within trichomonad cells may affect antibiotic susceptibility.

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.

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.

Associations between bacterial vaginosis, candida vaginitis, trichomonas vaginalis, and vaginal pathogenic community in Chinese women

BACKGROUND

To investigate the associations between Vaginal Pathogenic Community with Bacterial vaginosis, Candida vaginitis, and Trichomonas vaginalis in Chinese women.

METHOD

In this experiment, ten BV, nine VVC, eight TV patients, and four non-infected healthy women were recruited. The vaginal samples were collected from the vaginal orifice, the middle of the vagina, and vaginal fornix from every participant and conducted with next-generation sequencing (NGS). The NGS was based upon the analysis of bacterial 16S rRNA genes by using the Illumina Miseq system.

RESULTS

No significant difference in microbiome community structures was observed for the three sampling sites from the same subject. Compared with the healthy population, patients with BV and TV showed more diverse symptoms and had a lower amount of Lactobacillus but a higher number of BV-related bacteria like Atopobium, Dialister, Sneathia, Mobiluncus, and Prevotella. On the contrary, the species composition of the VVC group is relatively simple, which has a significantly high abundance of Lactobacillus. Eight genera, including Arcanobacterium, Clostridium, Moryella, Mobiluncus, Shuttleworthia, Dialister, Bulleidia, and Megasphaera, were closely correlated with BV. Among vaginal pathogenic bacteria, Anaerococcus, Lysobacter, Mycoplasma, Peptoniphilus, Sneathia, and Prevotella were more common, with higher copy numbers in the TV group.

CONCLUSIONS

The data outlined the overall structure of vaginal communities, indicating that BV and TV were touching related to a sharp increase in the rich taxonomy and diversity of vaginal microbiota. VVC group presented a lower variety, with a significantly high abundance of Lactobacillus.

Determination of metabolic activity in planktonic and biofilm cells of Mycoplasma fermentans and Mycoplasma pneumoniae by nuclear magnetic resonance

Mycoplasmas are fastidious microorganisms, typically characterised by their restricted metabolism and minimalist genome. Although there is reported evidence that some mycoplasmas can develop biofilms little is known about any differences in metabolism in these organisms between the growth states. A systematic metabolomics approach may help clarify differences associated between planktonic and biofilm associated mycoplasmas. In the current study, the metabolomics of two different mycoplasmas of clinical importance (Mycoplasma pneumoniae and Mycoplasma fermentans) were examined using a novel approach involving nuclear magnetic resonance spectroscopy and principle component analysis. Characterisation of metabolic changes was facilitated through the generation of high-density metabolite data and diffusion-ordered spectroscopy that provided the size and structural information of the molecules under examination. This enabled the discrimination between biofilms and planktonic states for the metabolomic profiles of both organisms. This work identified clear biofilm/planktonic differences in metabolite composition for both clinical mycoplasmas and the outcomes serve to establish a baseline understanding of the changes in metabolism observed in these pathogens in their different growth states. This may offer insight into how these organisms are capable of exploiting and persisting in different niches and so facilitate their survival in the clinical setting.

Comparative analysis of the vaginal microbiome of Chinese women with Trichomonas vaginalis and mixed infection

The high prevalence and serious long-term sequelae of Trichomonas vaginalis (TV) infection worldwide is of a particular concern; however, data regarding the differences in the composition of the vaginal microbiome in cases of single TV infection or mixed infections (i.e., presence of TV and bacterial vaginosis) are scarce. We employed metagenomic sequencing analyses to study gene expression in the vaginal microbiota of women with single TV infection and mixed infection. Women infected with only TV had significantly higher abundance of Mycoplasma, Prevotella, and Streptococcus compared to women without vaginal infection (control). Women infected with mixed infections had a significantly higher abundance of Mycoplasma, Prevotella, Streptococcus, Anaerococcus, Dialister, Peptostreptococcus, Peptoniphilus and a significantly lower abundance of Lactobacillus than TV alone. Mixed infections had a significantly higher abundance of Prevotella, Anaerococcus and Dialister. Our findings suggest that the bacterial community composition varies among healthy women, women with TV alone, and those with mixed infection, and we hypothesize that these bacterial vaginosis (BV)-associated bacterium may play a role in the pathogenesis and recurrence of TV. Probiotic pessaries may necessarily be the answer because shifting the vaginal microbiome and host responses is probably a complex undertaking.

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.

Mycoplasma hominis shows strain-dependent increase in resistance to selected antibiotics after symbiosis with Trichomonas vaginalis

OBJECTIVES

Mycoplasma hominis, a genetically heterogeneous, cell-wall-less bacterium, is able to live in symbiosis with the protozoan parasite Trichomonas vaginalis. Whilst the impact of this symbiosis on T. vaginalis has been investigated to a certain extent, less light has been shed on the influence on M. hominis.

METHODS

An in vitro minimum inhibitory concentration (MIC) study of the antimicrobial susceptibility of three clinical M. hominis isolates (V475, AKH136 and MhSS10) to clindamycin, moxifloxacin, ciprofloxacin and gentamicin was performed in dependence on symbiosis with T. vaginalis strain IR78.

RESULTS

Passaging of M. hominis through T. vaginalis led to an increase in MICs to all drugs investigated in M. hominis V475 and M. hominis MhSS10 (apart from gentamicin). Shifts from intermediate to resistant (MhSS10 for ciprofloxacin) and from susceptible to intermediate-resistant (V475 for gentamicin; P=0.015) were observed. Moreover, initial susceptibility of V475 to moxifloxacin (MIC=1.35μg/mL) was statistically significantly reduced (MIC=2.5μg/mL) following T. vaginalis passage concomitantly with mutations in the quinolone resistance-determining regions (QRDRs) of gyrA (S153L) and parC (E195G and K144R). In contrast, the susceptibility of M. hominis isolate AKH136 to all drugs investigated increased after passaging.

CONCLUSIONS

These findings suggest that symbiosis with T. vaginalis has an enhancing effect on selected antimicrobial resistances of distinct M. hominis isolates.

Mycoplasma hominis impacts gene expression in Trichomonas vaginalis

In Europe, up to 90% of isolated Trichomonas vaginalis strains are naturally infected with Mycoplasma hominis, a facultative pathogen of the human genital tract. The consequences of this endosymbiosis are not yet well understood. The aim of the current study was to evaluate the impact of natural and artificial infections with M. hominis on the RNA expression levels of metronidazole susceptibility-associated genes of T. vaginalis. Three T. vaginalis strains (TVSS10-, TVSS25-, G3) without M. hominis, as well as the same strains naturally (TVSS10+, TVSS25+) and artificially (G3-MhSS25, TVSS25-MhSS25) infected with M. hominis, were investigated for their expression profiles of three genes associated with metronidazole resistance (ferredoxin, flavin reductase 1 and pyruvate:ferredoxin oxidoreductase). The minimal inhibitory concentrations (MICs) of metronidazole were evaluated for all combinations and the respective M. hominis-free T. vaginalis strains were used as controls. The sole presence of M. hominis led to a down-regulation of metronidazole susceptibility-associated genes in all T. vaginalis strains tested. Interestingly, the effect was more prominent in the artificial symbioses. Moreover, a twofold enhancement of metronidazole tolerability was observed in three infected T. vaginalis strains, compared to the respective strains without M. hominis. In conclusion, M. hominis had an impact on gene expression in all T. vaginalis strains and on metronidazole MIC in all but one strain tested.

CRISPR/Cas9-mediated gene modification and gene knock out in the human-infective parasite Trichomonas vaginalis

The sexually-transmitted parasite Trichomonas vaginalis infects ~1/4 billion people worldwide. Despite its prevalence and myriad adverse outcomes of infection, the mechanisms underlying T. vaginalis pathogenesis are poorly understood. Genetic manipulation of this single-celled eukaryote has been hindered by challenges presented by its complex, repetitive genome and inefficient methods for introducing DNA (i.e. transfection) into the parasite. Here, we have developed methods to increase transfection efficiency using nucleofection, with the goal of efficiently introducing multiple DNA elements into a single T. vaginalis cell. We then created DNA constructs required to express several components essential to drive CRISPR/Cas9-mediated DNA modification: guide RNA (gRNA), the Cas9 endonuclease, short oligonucleotides and large, linearized DNA templates. Using these technical advances, we have established CRISPR/Cas9-mediated repair of mutations in genes contained on circular DNA plasmids harbored by the parasite. We also engineered CRISPR/Cas9 directed homologous recombination to delete (i.e. knock out) two non-essential genes within the T. vaginalis genome. This first report of the use of the CRISPR/Cas9 system in T. vaginalis greatly expands the ability to manipulate the genome of this pathogen and sets the stage for testing of the role of specific genes in many biological processes.

Endosymbiosis and its significance in dermatology

Proposed at the beginning of the twentieth century to explain the origin of eukaryotic organelles from prokaryotes, endosymbiosis is now medically defined by various interaction patterns between microorganisms and their residing hosts, best exemplified by the bacterial endosymbiont Wolbachia identified in arthropods and filarial nematodes, which can influence normal development, reproduction, survival and transmission of the hosts. Based on the transmission modes, vertical or horizontal, and the function of the endosymbionts, the host-symbiont dependence can be divided into primary or secondary. In dermatology, the role of endosymbionts in skin ectoparasitosis has aroused great interests in the past years. Riesia pediculicola is a primary bacterial endosymbiont in body lice Pediculus humanus, and supplement their hosts with vitamin B, especially pantothenic acid. In cimicosis, the Gram-negative Wolbachia can synthesize biotin and riboflavin, which are crucial for the growth and reproduction of the bedbug Cimex lectularius. In human demodicosis and rosacea, further study is required to prove the pathogenic role of the Gram-negative bacteria Bacillus oleronius or the Gram-positive bacteria Bacillus cereus demonstrated in the Demodex mites. The high infection rate of adult female ticks Ixodes ricinus with the Gram-negative bacteria Midichloria mitochondrii present in the mitochondria in diverse ovarian cells, with the high seroprevalence rate in tick-exposed subjects, raises the possibility that this non-pathogenic endosymbiont may play a role in immune response and successful transmission of the tick-borne pathogen. The anaerobic protozoan Trichomonas vaginalis and bacteria Mycoplasma hominis are two obligate parasites in the urogenital epithelium, with partially overlapping symptoms. Intracellular localization of Mycoplasma hominis can avoid host immune response and penetration of antibiotics, while Trichomonas vaginalis infected with Mycoplasma hominis seems to have a higher cytopathic activity and amoeboid transformation rate. Further study on the biology and pathogenesis of different endosymbionts in dermatological parasitosis will help for the development of new treatment modalities.

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.

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.

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.

Metabolic Capacity of Mitochondrion-related Organelles in the Free-living Anaerobic Stramenopile Cantina marsupialis

Functionally and morphologically degenerate mitochondria, so-called mitochondrion-related organelles (MROs), are frequently found in eukaryotes inhabiting hypoxic or anoxic environments. In the last decade, MROs have been discovered from a phylogenetically broad range of eukaryotic lineages and these organelles have been revealed to possess diverse metabolic capacities. In this study, the biochemical characteristics of an MRO in the free-living anaerobic protist Cantina marsupialis, which represents an independent lineage in stramenopiles, were inferred based on RNA-seq data. We found transcripts for proteins known to function in one form of MROs, the hydrogenosome, such as pyruvate:ferredoxin oxidoreductase, iron-hydrogenase, acetate:succinate CoA-transferase, and succinyl-CoA synthase, along with transcripts for acetyl-CoA synthetase (ADP-forming). These proteins possess putative mitochondrial targeting signals at their N-termini, suggesting dual ATP generation systems through anaerobic pyruvate metabolism in Cantina MROs. In addition, MROs in Cantina were also shown to share several features with canonical mitochondria, including amino acid metabolism and an "incomplete" tricarboxylic acid cycle. Transcripts for all four subunits of complex II (CII) of the electron transport chain were detected, while there was no evidence for the presence of complexes I, III, IV, or F1Fo ATPase. Cantina MRO biochemistry challenges the categories of mitochondrial organelles recently proposed.

From Genome to Structure and Back Again: A Family Portrait of the Transcarbamylases

Enzymes in the transcarbamylase family catalyze the transfer of a carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate. The two best-characterized members, aspartate transcarbamylase (ATCase) and ornithine transcarbamylase (OTCase), are present in most organisms from bacteria to humans. Recently, structures of four new transcarbamylase members, N-acetyl-l-ornithine transcarbamylase (AOTCase), N-succinyl-l-ornithine transcarbamylase (SOTCase), ygeW encoded transcarbamylase (YTCase) and putrescine transcarbamylase (PTCase) have also been determined. Crystal structures of these enzymes have shown that they have a common overall fold with a trimer as their basic biological unit. The monomer structures share a common CP binding site in their N-terminal domain, but have different second substrate binding sites in their C-terminal domain. The discovery of three new transcarbamylases, l-2,3-diaminopropionate transcarbamylase (DPTCase), l-2,4-diaminobutyrate transcarbamylase (DBTCase) and ureidoglycine transcarbamylase (UGTCase), demonstrates that our knowledge and understanding of the spectrum of the transcarbamylase family is still incomplete. In this review, we summarize studies on the structures and function of transcarbamylases demonstrating how structural information helps to define biological function and how small structural differences govern enzyme specificity. Such information is important for correctly annotating transcarbamylase sequences in the genome databases and for identifying new members of the transcarbamylase family.

Trichomonas vaginalis virulence factors: an integrative overview

The elusive nature of Trichomonas vaginalis, the most common, non-viral, sexually transmitted pathogen has hampered our knowledge of its significance for human health for over 150 years. The combination of epidemiology, molecular cell biology, immunology and more recently genomics and other allied omics data, are all contributing at shedding new light onto what is increasingly recognised as a significant human pathogen leading to important health sequelae due to multifaceted interactions with its human host, the human microbiota, bacterial pathogens and viruses. The integrations of these various data are contributing in important ways to refining our understanding of the parasite pathobiology and virulent factors. Indeed, it is increasingly recognised that to rationalise the development of effective prophylactic and therapeutic treatments for human pathogens it is important to integrate the broadest possible spectrum of human-microbial-parasite-virus interactions in relation to qualitative and quantitative variations in the human innate and adaptive defence responses. This short review aims at providing an integrative overview of T vaginalis virulent factors by taking into account the importance of the human-microbiota-parasite-virus interplay in human health. It also highlights selected cellular characteristics of the parasite often overlooked in the biological and medical literature.

Unique vaginal microbiota that includes an unknown Mycoplasma-like organism is associated with Trichomonas vaginalis infection

BACKGROUND

The prevalence of Trichomonas vaginalis infection is highest in women with intermediate Nugent scores. We hypothesized that the vaginal microbiota in T. vaginalis-infected women differs from that in T. vaginalis-uninfected women.

METHODS

Vaginal samples from 30 T. vaginalis-infected women were matched by Nugent score to those from 30 T. vaginalis-uninfected women. Equal numbers of women with Nugent scores categorized as normal, intermediate, and bacterial vaginosis were included. The vaginal microbiota was assessed using 454 pyrosequencing analysis of polymerase chain reaction-amplified 16S ribosomal RNA gene sequences. The 16S ribosomal RNA gene sequence of an unknown organism was obtained by universal bacterial polymerase chain reaction amplification, cloning, and sequencing.

RESULTS

Principal coordinates analysis of the pyrosequencing data showed divergence of the vaginal microbiota in T. vaginalis-infected and T. vaginalis-uninfected patients among women with normal and those with intermediate Nugent scores but not among women with bacterial vaginosis. Cluster analysis revealed 2 unique groups of T. vaginalis-infected women. One had high abundance of Mycoplasma hominis and other had high abundance of an unknown Mycoplasma species. Women in the former group had clinical evidence of enhanced vaginal inflammation.

CONCLUSIONS

T. vaginalis may alter the vaginal microbiota in a manner that is favorable to its survival and/or transmissibility. An unknown Mycoplasma species plays a role in some of these transformations. In other cases, these changes may result in a heightened host inflammatory response.