Is Trichomonas tenax a Parasite or a Commensal?

Evaluation of periodontitis parameters and plaque examination by microscopy: a report on 20 patients

The protozoan parasite Entamoeba gingivalis has long been detected in diseased gingival pockets. The parasite is found in 81% of diseased sites using PCR and in up to 100% using microscopy, whereas it is mostly absent from healthy gingival sites. The purpose of this study on 20 periodontitis patients was to analyze the characteristic biofilm using phase-contrast microscopy and evaluate the results of a novel antiparasitic, anti-inflammatory therapeutical approach. The therapeutic strategy, termed "Periodontal Healing Protocol Bonner Dunoyé" (PHPBD), is implemented in monthly appointments for 8 months, and a control visit at one year. It involves a disinfection protocol, subgingival calculus removal, patient training and the microscopic analysis of periodontal biofilm sulci. The practitioner also records bleeding on probing (BOP) and pocket depth (PD) to quantify healing. In all cases, the initial biofilm composed mainly of parasites, neutrophils, spirochetes, and other motile bacteria was progressively replaced by a white blood cell-free biofilm, consisting of motionless coccoid bacteria, filaments, and epithelial cells, indicative of healthy periodontium. Results were stable from month 8 to month 12. At one year, both BOP and PD values were greatly reduced (96%-100% decrease) compared to initial levels. The average sulcus clinical pocket healing toward the 1-3 mm PD group teeth was close to 99% overall patients. In conclusion, implementation of PHPBD appears to result in complete healing of periodontitis within 12 months, as determined by BOP, PD, biofilm microscopic monitoring and elimination of motile bacteria, parasites, and inflammatory cells. Thus, periodontal dysbiosis can be microscopically guided toward predictable eubiosis. Further studies are needed to evaluate long-term benefits.

Comparative genomics between Trichomonas tenax and Trichomonas vaginalis: CAZymes and candidate virulence factors

Introduction

The oral trichomonad Trichomonas tenax is increasingly appreciated as a likely contributor to periodontitis, a chronic inflammatory disease induced by dysbiotic microbiota, in humans and domestic animals and is strongly associated with its worst prognosis. Our current understanding of the molecular basis of T. tenax interactions with host cells and the microbiota of the oral cavity are still rather limited. One laboratory strain of T. tenax (Hs-4:NIH/ATCC 30207) can be grown axenically and two draft genome assemblies have been published for that strain, although the structural and functional annotation of these genomes is not available.

Methods

GenSAS and Galaxy were used to annotate two publicly available draft genomes for T. tenax, with a focus on protein-coding genes. A custom pipeline was used to annotate the CAZymes for T. tenax and the human sexually transmitted parasite Trichomonas vaginalis, the most well-characterized trichomonad. A combination of bioinformatics analyses was used to screen for homologs of T. vaginalis virulence and colonization factors within the T. tenax annotated proteins.

Results

Our annotation of the two T. tenax draft genome sequences and their comparison with T. vaginalis proteins provide evidence for several candidate virulence factors. These include candidate surface proteins, secreted proteins and enzymes mediating potential interactions with host cells and/or members of the oral microbiota. The CAZymes annotation identified a broad range of glycoside hydrolase (GH) families, with the majority of these being shared between the two Trichomonas species.

Discussion

The presence of candidate T. tenax virulence genes supports the hypothesis that this species is associated with periodontitis through direct and indirect mechanisms. Notably, several GH proteins could represent potential new virulence factors for both Trichomonas species. These data support a model where T. tenax interactions with host cells and members of the oral microbiota could synergistically contribute to the damaging inflammation characteristic of periodontitis, supporting a causal link between T. tenax and periodontitis.

Prospective observational study of Trichomonas tenax infection in patients with pneumonia

Trichomonas tenax, an oral commensal parasite commonly found in the human mouth, is associated with periodontitis and poor oral hygiene. However, it has also been identified in the bronchoalveolar lavage fluid (BALF) of individuals with lung diseases. Notably, significant quantities of T. tenax have been isolated following bronchoscopy in cases of empyema and acute respiratory distress syndrome (ARDS). Furthermore, research has demonstrated its ability to induce inflammation in pulmonary epithelial cells. To comprehend the potential role of T. tenax in pneumonia, it is crucial to elucidate the relationship between the parasite and the disease. We investigated the clinical factors associated with T. tenax infection in patients with pneumonia. Employing nested polymerase chain reactions, we amplified nucleic acids from BALF and analyzed the relationships between T. tenax and various clinical factors. Our data revealed a significant association between T. tenax and bacterial infections, high pneumonia severity index (PSI) scores, nasogastric tube feeding, and pulmonary complications. Logistic regression analyses also showed strong associations between T. tenax and these clinical factors in pneumonia patients. These findings suggest that T. tenax infection in pneumonia is accompanied by bacterial infection and severe clinical manifestations.

Prolonged survival of venereal Tritrichomonas foetus parasite in the gastrointestinal tract, bovine fecal extract, and water

IMPORTANCE

Nowadays, the routine herd diagnosis is usually performed exclusively on bulls, as they remain permanently infected, and prevention and control of Tritrichomonas foetus transmission are based on identifying infected animals and culling practices. The existence of other forms of transmission and the possible role of pseudocysts or cyst-like structures as resistant forms requires rethinking the current management and control of this parasitic disease in the future in some livestock regions of the world.

Microbial underdogs: exploring the significance of low-abundance commensals in host-microbe interactions

Our understanding of host-microbe interactions has broadened through numerous studies over the past decades. However, most investigations primarily focus on the dominant members within ecosystems while neglecting low-abundance microorganisms. Moreover, laboratory animals usually do not have microorganisms beyond bacteria. The phenotypes observed in laboratory animals, including the immune system, have displayed notable discrepancies when compared to real-world observations due to the diverse microbial community in natural environments. Interestingly, recent studies have unveiled the beneficial roles played by low-abundance microorganisms. Despite their rarity, these keystone taxa play a pivotal role in shaping the microbial composition and fulfilling specific functions in the host. Consequently, understanding low-abundance microorganisms has become imperative to unravel true commensalism. In this review, we provide a comprehensive overview of important findings on how low-abundance commensal microorganisms, including low-abundance bacteria, fungi, archaea, and protozoa, interact with the host and contribute to host phenotypes, with emphasis on the immune system. Indeed, low-abundance microorganisms play vital roles in the development of the host's immune system, influence disease status, and play a key role in shaping microbial communities in specific niches. Understanding the roles of low-abundance microbes is important and will lead to a better understanding of the true host-microbe relationships.

Trichomonas tenax induces barrier defects and modulates the inflammatory cytotoxicity of gingival and pulmonary epithelial cells

BACKGROUND

Trichomonas tenax is a single-cell flagellated anaerobic organism, commensal in the human oral cavity. Although a previous study indicated that T. tenax could cause cell damage and phagocytose host epithelial cells, its pathological effects on gum cells remain unknown. Furthermore, several case reports have detected T. tenax in several patients with empyema and/or pleural effusion, which may have been aspirated from the oral cavity. However, the cytotoxic effects and immune responses of alveolar cells are unknown. Therefore, we aimed to determine the cytotoxic and immune effects of T. tenax on gums and pulmonary cell lines. The cytopathic effect and lactate dehydrogenase (LDH) cytotoxicity assays were used to determine the level of cell damage in gum and lung epithelial cells. Western blot was used to determine the disruption of cell junctions. Finally, epithelial cell cytokines were measured using ELISA to elucidate the immune response to T. tenax.

RESULTS

We found that T. tenax induced a cytotoxic effect on gum epithelial cells by disrupting cell junctions; however, it hardly triggered cellular damage in alveolar A549 cells and mucoepidermoid NCI-H292 cells. Furthermore, T. tenax induced the production of IL-6 at a low multiplicity of infection (MOI) in gum, A549, and NCI-H292 cells.

CONCLUSIONS

Our results suggest that T. tenax can trigger gingival cell cytotoxicity, disrupt cell junctions, and induce IL-6 production in gingival and pulmonary cell lines.

Ancient and pervasive expansion of adaptin-related vesicle coat machinery across Parabasalia

The eukaryotic phylum Parabasalia is composed primarily of anaerobic, endobiotic organisms such as the veterinary parasite Tritrichomonas foetus and the human parasite Trichomonas vaginalis, the latter causing the most prevalent, non-viral, sexually transmitted disease world-wide. Although a parasitic lifestyle is generally associated with a reduction in cell biology, T. vaginalis provides a striking counter-example. The 2007 T. vaginalis genome paper reported a massive and selective expansion of encoded proteins involved in vesicle trafficking, particularly those implicated in the late secretory and endocytic systems. Chief amongst these were the hetero-tetrameric adaptor proteins or 'adaptins', with T. vaginalis encoding ∼3.5 times more such proteins than do humans. The provenance of such a complement, and how it relates to the transition from a free-living or endobiotic state to parasitism, remains unclear. In this study, we performed a comprehensive bioinformatic and molecular evolutionary investigation of the heterotetrameric cargo adaptor-derived coats, comparing the molecular complement and evolution of these proteins between T. vaginalis, T. foetus and the available diversity of endobiotic parabasalids. Notably, with the recent discovery of Anaeramoeba spp. as the free-living sister lineage to all parabasalids, we were able to delve back to time points earlier in the lineage's history than ever before. We found that, although T. vaginalis still encodes the most HTAC subunits amongst parabasalids, the duplications giving rise to the complement took place more deeply and at various stages across the lineage. While some duplications appear to have convergently shaped the parasitic lineages, the largest jump is in the transition from free-living to endobiotic lifestyle with both gains and losses shaping the encoded complement. This work details the evolution of a cellular system across an important lineage of parasites and provides insight into the evolutionary dynamics of an example of expansion of protein machinery, counter to the more common trends observed in many parasitic systems.

Entamoeba gingivalis and Trichomonas tenax: Protozoa parasites living in the mouth

OBJECTIVE

This review article aims to summarize the existing data on the history, biology and potential pathogenicity of Entamoeba gingivalis and Trichomonas tenax in periodontal disease, as well as the available techniques for laboratory diagnosis.

DESIGN

A detailed review of scientific literature available up to October 1, 2022 in three databases (PubMed, Scopus and Web of Science) was performed relevant to biology, biochemistry, epidemiology, and experimental studies on infection by E. gingivalis and T. tenax, as well as laboratory techniques for the diagnosis of both protozoa in periodontal diseases.

RESULTS

Accumulated evidence over the decades indicates that the protozoa E. gingivalis and T. tenax are able to interact with host cells and induce inflammation in the periodontal tissue by promoting the expression of pro-inflammatory molecules and the recruitment of neutrophils, contributing to the periodontal disease process. Among the available techniques for the laboratory diagnosis, culture and molecular assays seems to be the best tools for detection of both protozoan parasites.

CONCLUSIONS

E. gingivalis and T. tenax are potentially pathogens that colonize the oral cavity of humans and may cause periodontal disease.

Tritrichomonas foetus Cell Division Involves DNA Endoreplication and Multiple Fissions

Tritrichomonas foetus and Trichomonas vaginalis are extracellular flagellated parasites that inhabit animals and humans, respectively. Cell division is a crucial process in most living organisms that leads to the formation of 2 daughter cells from a single mother cell. It has been assumed that T. vaginalis and T. foetus modes of reproduction are exclusively by binary fission. However, here, we showed that multinuclearity is a phenomenon regularly observed in different T. foetus and T. vaginalis strains in standard culture conditions. Additionally, we revealed that nutritional depletion or nutritional deprivation led to different dormant phenotypes. Although multinucleated T. foetus are mostly observed during nutritional depletion, numerous cells with 1 larger nucleus have been observed under nutritional deprivation conditions. In both cases, when the standard culture media conditions are restored, the cytoplasm of these multinucleated cells separates, and numerous parasites are generated in a short period of time by the fission multiple. We also revealed that DNA endoreplication occurs both in large and multiple nuclei of parasites under nutritional deprivation and depletion conditions, suggesting an important function in stress nutritional situations. These results provide valuable data about the cell division process of these extracellular parasites. IMPORTANCE Nowadays, it's known that T. foetus and T. vaginalis generate daughter cells by binary fission. Here, we report that both parasites are also capable of dividing by multiple fission under stress conditions. We also demonstrated, for the first time, that T. foetus can increase its DNA content per parasite without concluding the cytokinesis process (endoreplication) under stress conditions, which represents an efficient strategy for subsequent fast multiplication when the context becomes favorable. Additionally, we revealed the existence of novel dormant forms of resistance (multinucleated or mononucleated polyploid parasites), different than the previously described pseudocysts, that are formed under stress conditions. Thus, it is necessary to evaluate the role of these structures in the parasites' transmission in the future.

Trichomonas tenax: A Neglected Protozoan Infection in the Oral Cavities of Humans and Dogs-A Scoping Review

Trichomonas tenax is a flagellated protozoan parasite found in the oral cavities of humans and animals and has been associated with periodontal disease, the most prevalent inflammatory disease affecting them all. Studies have shown that T. tenax can cause damage to mammalian cells and secretes virulent proteins, such as cysteine. It is presently considered zoonotic. Despite the few studies that have been done, the pathogenicity of this oral protozoan is still not fully understood. A database search was performed in July 2022 using PubMed and Google Scholar to retrieve data eligible for this study. PRISMA-ScR guidelines were followed to conduct this scoping review. A total of 321 articles were found with 87 included in this review after applying the exclusion criteria. Due to its increasing prevalence worldwide in both humans and dogs, detecting and elucidating the pathogenicity of this parasite is paramount for effective global control and prevention of periodontal disease. However, there is a paucity in the literature on this neglected zoonotic trichomonad, which is in large contrast to the closely related human pathogen T. vaginalis. Here, we comprehensively review the history, morphology and reproduction, host, prevalence, diagnosis, pathogenicity, control, and prevention of T. tenax. Hopefully, this article will call attention to both medical and veterinary professionals as well as epidemiologists on this most neglected and zoonotic protozoan. More epidemiological and clinical studies need to be conducted on T. tenax to gain a better understanding of its pathogenicity, to increase the chances of developing effective drugs to aid in the control of this oral parasite, and reduce the spread of periodontal disease worldwide.

Molecular prevalence and zoonotic potential of trichomonads from oral cavities in household dogs

This study investigated the molecular prevalence of oral trichomonads in household dogs. Of the 144 dogs, 21 (14.6%, 21/144) tested positive for oral trichomonads. The prevalence was significantly higher in dogs with severe gingivitis (gingival index 3: 30.0%, 8/26) than that in normal dogs (gingival index 0: 2.7%, 1/37). Therefore, an interaction between oral trichomonads and the development of periodontal disease is suggested. Of the 21 positive samples, 16 isolates were T. brixi, four isolates were T. tenax, and one was Tetratrichomonas sp. Considering T. tenax is recognized as a zoonotic agent, transmission between dogs and humans cannot be neglected.

Cytokine array analysis of mediators produced by human macrophages stimulated with Trichomonastenax

The incidence of oral colonization by the protozoan Trichomonas tenax correlates with gingival inflammation and periodontitis in humans. To determine whether T. tenax might contribute to inflammation by eliciting cytokines from human cells, differentiated THP-1 (dTHP-1) macrophages were cultured with live or sonicated T. tenax trophozoites, and the conditioned media were assayed for 36 different mediators by a membrane-based cytokine array. Scanning densitometry of the membranes revealed that live T. tenax trophozoites stimulated secretion of interleukin-8 (IL-8), macrophage migration inhibitory factor (MIF), IL-1β, intercellular adhesion molecule-1 (ICAM-1), and IL-1 receptor antagonist (IL-1ra) from dTHP-1 macrophages. T. tenax lysates stimulated release of IL-8, MIF, and IL-1ra. Despite often being classified as a commensal organism, T. tenax elicited a wider variety of cytokines than the human urogenital pathogen, T. vaginalis, which elicited only IL-8 and MIF production from dTHP-1 cells.

Tissue-resident memory T cells in the urogenital tract

Our understanding of T cell memory responses changed drastically with the discovery that specialized T cell memory populations reside within peripheral tissues at key pathogen entry sites. These tissue-resident memory T (T_RM) cells can respond promptly to an infection without the need for migration, proliferation or differentiation. This rapid and local deployment of effector functions maximizes the ability of T_RM cells to eliminate pathogens. T_RM cells do not circulate through peripheral tissues but instead form isolated populations in the skin, gut, liver, kidneys, the reproductive tract and other organs. This long-term retention in the periphery might allow T_RM cells to fully adapt to the local conditions of their environment and mount customized responses to counter infection and tumour growth in a tissue-specific manner. In the urogenital tract, T_RM cells must adapt to a unique microenvironment to confer protection against potential threats, including cancer and infection, while preventing the onset of auto-inflammatory disease. In this Review, we discuss insights into the diversification of T_RM cells from other memory T cell lineages, the adaptations of T_RM cells to their local environment, and their enhanced capacity to counter infection and tumour growth compared with other memory T cell populations, especially in the urogenital tract.

A Loop-Mediated Isothermal Amplification (LAMP) Assay Specific to Trichomonas tenax Is Suitable for Use at Point-of-Care

Trichomonas tenax is a flagellated protozoan that inhabits the human and canine oral cavity in patients with poor oral hygiene and periodontal disease. The loop-mediated isothermal amplification (LAMP) assay could provide clinicians with a quick, cheap and reliable diagnostic test used for the detection of T. tenax in various settings. In this study, we aimed to develop a LAMP assay that can detect T. tenax with high sensitivity and specificity. A set of LAMP primers were specifically designed to detect the ITS and 5.8S rRNA gene of T. tenax. The newly developed LAMP assay was 1000 times more sensitive than conventional PCR. The limit of detection of the LAMP assay was 10 fg of genomic DNA, or 0.2-1 cell. Moreover, the LAMP assay was specific, resulting in no cross-reaction even with a closely related protozoan T. vaginalis or other microorganisms (Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Candida albicans) used. The present LAMP assay can be performed directly without prior DNA extraction, making the assay an easy, fast, cheap, specific and sensitive diagnostic tool for the detection of T. tenax at the point-of-care of both medical and veterinary clinics in developed and developing countries.

Oral cavity protozoa relevant in the practice of dentistry

Introduction: Oral cavity is the colonization site of most diverse microorganisms. The homeostasis of oral microbioma is affected by numerous factors. Periodontal diseases occur as a consequence of disturbed oral microbioma homeostasis, when an inflammatory reaction occurs in the periodontal tissue. The impact of parasites on periodontal pathophysiology has not been sufficiently studied, and present and future research should hopefully answer quite a few questions concerning the issue. Aim of the paper: In the light of the present knowledge of the pathogenesis, diagnosis and epidemiology of oral cavity infections caused by Entamoeba gingivalis and Trichomonas tenax, the aim of the paper was review of literature which could to point to the importance of protozoa in the practice of dentistry and to possible oral cavity manifestations of parasitic infections relevant for public health. Conclusion: Dentists have an essential role in the diagnosis of oral diseases caused by oral cavity protozoa, and protozoa relevant for public health that produce systemic infections, the pathological changes of which may manifest in the oral cavity. Their identification represents a challenge and requires multidisciplinary approach for a timely diagnosis and adequate management.

Prevalence of trichomonads in the cloaca of wild wetland birds in the Netherlands

Severe granulomatosis in productive layer chickens due to Tetratrichomonas gallinarum strain 13/16632 infection occurred in 2013 and 2017 on farms situated in a wetland area in the Netherlands. We hypothesized that wetland birds could be the source of the infection. Therefore, a prevalence study on trichomonads was performed by analysing cloaca swabs of 526 birds belonging to 13 species of wetland birds. The number of birds sampled ranged from 1 to 275 per species. Birds were sampled at 15 locations in the Netherlands. DNA extracted from the cloaca swabs was subjected to nested PCR using trichomonad-specific primers targeting the internal transcribed spacer 1 (ITS1)-5.8S rRNA-ITS2 region followed by cloning and sequencing. In nine bird species, trichomonads were detected; the overall prevalence was 9% (47/526), while the prevalence in the five species for which a substantial number of birds were examined (at least 39 per species) ranged from 4% to 24%. Three trichomonad species were found: T. gallinarum, Trichomonas tenax and Simplicimonas sp. of which T. gallinarum dominated. The virulent T. gallinarum strain 13/16632 was not detected, but closely related strains were. Phylogenetic analysis revealed that all T. gallinarum isolates belonged to two clusters within lineage 15 of Tetratrichomonas lineages. All T. tenax isolates were identical and clustered with reference strain H95, while Simplicimonas sp. isolates showed large genetic diversity. Some isolates may represent a new species of the genus Simplicimonas. We conclude that trichomonads are widespread amongst wetland birds, raising the question, amongst others, of their relevance for commercial poultry. RESEARCH HIGHLIGHTSTrichomonads occur among wild wetland birds in the Netherlands.T. gallinarum is the dominant trichomonad species in the cloaca of wetland birds.Some T. gallinarum isolates are closely related to a strain causing granulomas in layer chickens.Some isolates may represent a new species of the genus Simplicimonas.

The Neglected Role of Trichomonas tenax in Oral Diseases: A Systematic Review and Meta-analysis

PURPOSE

Trichomonas tenax (T. tenax) is a commensal flagellated protozoan found in periodontal microenvironment of the oral cavity, with a possible role in periodontal diseases. The purpose of the present systematic review and meta-analysis was to determine the worldwide prevalence of T. tenax infection and to show the neglected association of this parasitic infection with oral diseases.

METHODS

To find literatures published until August 2020, five English databases (PubMed, Scopus, Science Direct, Web of Science and Google Scholar) were explored. Finally, 65 papers were qualified to be included in the current study.

RESULTS

Our results revealed a global pooled prevalence of 17% (95% CI 14-22%) for T. tenax infection. The highest prevalence was estimated at 56% (42-69%) in Chile, while the lowest prevalence was related to Kenya with 3% (1-6%). The age-based analysis found that the infection was most common in 46-55 mean age group with 15% (0-100%). The overall prevalence regarding culture method, molecular method and direct method was 21% (12-32%), 19% (8-35%) and 17% (12-23%), respectively. Moreover, the subgroup analysis showed the pooled prevalence in patient with candidiasis [22% (3-52%)], gingivitis [21% (9-36%)] and periodontitis [27% (10-48%)].

CONCLUSION

Our study specified a connection between T. tenax protozoa and periodontitis disease. However, more epidemiological studies as well as clinical trials are needed to precisely identify this relation.

Presence of Trichomonas spp. in oral ulcerations of a patient with kidney transplant. A case report

Mucosal ulcerations are an oral complication that can often affect kidney transplant patients, mostly due to the effect of immunosuppression. It has been frequently reported drug-induced ulceration or lymphoproliferative disorders with buccal manifestations however, some unusual disorders should also be considered, such as fungal infections, viruses, as well as opportunistic infection by other microorganisms. Determining the etiology and differential diagnose from other causes of mouth ulcers is very important for the adequate treatment of said lesion. Dental health of patients should also be taken into the account prior to the transplant surgery, since periodontal pockets are the main niche of microbial reservoir. Moreover, mixed with oral microbiota, parasites such as Trichomonas spp. can be found in the dental plaque of patients with periodontal disease. Particularly, Trichomonas spp. are anaerobic motile-flagellated protozoa that can both induce tissue damage and exacerbate preexistent injuries in vaginal and oral mucosa. Parasitic infection in the oral cavity has not been well studied and it is thought to be underreported. In the present study we report the first case in literature of presence of Trichomonas spp. as a potential etiological factor of the oral ulcerations of a kidney transplanted patient that remitted after antibiotic treatment.

Key words:Immunosuppression, protozoan, buccal lesion, oral mucosa, kidney transplant.

Assessment of the role of Trichomonas tenax in the etiopathogenesis of human periodontitis: A systematic review

Objective

This systematic review was to assess the presence of Trichomonas tenax in patients with periodontitis and to elucidate its potential role in the onset and development of this disease.

Method

Systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and by consulting the five databases: Medline, Science Direct, Web of Science, Dentistry and Oral Science Sources and Cochrane Central Register of Controlled Trials. Following Koch’s postulates revisited by Socransky as PICO framework, this collection data was only including full text of clinical trials concerning patients with periodontitis, case-reports and in vitro research published between 1960 and March 2019.

Results

On the 376 studies identified, only 25 fulfilled our eligible criteria. Most of these studies were in vitro research articles designed to evaluate potential virulence factors, and others were clinical trials (case-control studies, randomized controlled trial) and case-reports. The analysis of these papers has shown that i) Trichomonas tenax is more frequently detected in dental biofilm from sites with periodontitis than in healthy sites; ii) this live flagellate seems capable of producing diverse enzymes that could participate in periodontal breakdown and has the capacity to adhere to epithelial cells, its lysed form could induce the synthesis of IL-8 from macrophage cell lines; iii) the impact of non-surgical treatment of periodontitis have not been thoroughly evaluated on the presence of T. tenax

Conclusions

This systematic review has reported the presence of T. tenax more frequently in diseased than healthy sites and the capacity of this flagellate to synthesis enzymes which could participate to the degradation of periodontal tissues. Nevertheless, these data do not meet all the postulates and are not enough to provide firm conclusions about the role of T. tenax in the etiopathogenesis of periodontitis.

Observational cross-sectional study of Trichomonas tenax in patients with periodontal disease attending a Chilean university dental clinic

BACKGROUND

The oral flagellated protozoan Trichomonas tenax has been associated with patients with periodontal disease. However, no recent studies have been conducted on the prevalence of T. tenax in Chile. The aim of this study was to determine the presence of T. tenax in patients with periodontal disease, admitted to the Dental Clinic of the University of Antofagasta, Chile, through Polymerase Chain Reaction (PCR) amplification of the beta-tubulin gene.

METHODS

An observational, cross-sectional study was conducted on 50 patients diagnosed with periodontal disease, 20 of them with gingivitis and 30 with periodontitis. T. tenax was identified by PCR amplification of the beta-tubulin gene. Associations between the protozoan and periodontal disease or the presence of risk factors to establish T. tenax infection were determined using the chi-square test and binary logistic regression analysis.

RESULTS

T. tenax was present in 28 out of 50 (56%) of patients with periodontal disease, and was more prevalent when associated with periodontitis (21 out of 30; 70%) than dental plaque-induced gingivitis (7 out of 20; 35%). Non-statistically-significant associations were observed between the presence of T. tenax and age, gender, smoking habit or diabetes. Statistically significant associations were observed between the presence of T. tenax and periodontal disease, and between T. tenax and the Periodontal Screening and Recording (PSR) index.

CONCLUSION

T. tenax showed a high presence in patients with progressive states of periodontal diseases. Consequently, T. tenax detection is strongly recommended in patients with periodontal disease diagnosis and with a PSR index greater than 3.

Aberrant and accidental trichomonad flagellate infections: rare or underdiagnosed?

The clinical significance and frequency of human infections with trichomonad flagellates in aberrant locations (locations other than the predilection sites) and accidental infections (infections with non-human trichomonads) are unclear. The total number of case reports in the literature is low, with the identification of the infection largely the outcome of investigations for the cause of clinical signs. At least seven species have been identified in either aberrant or accidental infections, with these infections occurring worldwide. Results of prospective and retrospective surveys of adults with respiratory disease suggest that aberrant and accidental trichomonad infections are less rare than the number of case reports suggest, with Trichomonas tenax being the most frequent. Surveys of neonates and infants suggest that aberrant Trichomonas vaginalis infections can be higher and more serious than suggested by the few case reports. The density and location of infection might be as important, if not more so, than species in determining pathogenicity. Molecular diagnostic methods including DNA sequencing can be used to better diagnose infections and enable identification to assist in determining the clinical significance of different species. Raising awareness of these infections among clinicians and adding them to their differential lists are strongly suggested.

In-Depth Quantitative Proteomic Analysis of Trophozoites and Pseudocysts of Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted anaerobic parasite that infects humans causing trichomoniasis, a common and ubiquitous sexually transmitted disease. The life cycle of this parasite possesses a trophozoite form without a cystic stage. However, the presence of nonproliferative and nonmotile, yet viable and reversible spherical forms with internalized flagella, denominated pseudocysts, has been commonly observed for this parasite. To understand the mechanisms involved in the formation of pseudocysts, we performed a mass spectrometry-based high-throughput quantitative proteomics study using a label-free approach and functional assays by biochemical and flow cytometric methods. We observed that the morphological transformation of trophozoite to pseudocysts is coupled to (i) a metabolic shift toward a less glycolytic phenotype; (ii) alterations in the abundance of hydrogenosomal iron-sulfur cluster (ISC) assembly machinery; (iii) increased abundance of regulatory particles of the ubiquitin-proteasome system; (iv) significant alterations in proteins involved in adhesion and cytoskeleton reorganization; and (v) arrest in G2/M phase associated with alterations in the abundance of regulatory proteins of the cell cycle. These data demonstrate that pseudocysts experience important physiological and structural alterations for survival under unfavorable environmental conditions.

Presence of trichomonads in subgingival biofilm of patients with periodontitis: preliminary results

This study aims to evaluate the prevalence of trichomonads in the subgingival biofilm of patients with periodontitis. Secondarily, the trichomonad presence was related to patient characteristics and periodontal clinical parameters, in order to highlight the factor favoring the development of these protozoans. Subgingival biofilm samples were collected from at least two diseased and one healthy site in 50 patients suffering from periodontitis. Trichomonads were identified using phase contrast microscopy. All patient characteristics and periodontal clinical parameter data were then statistically analyzed. From the 50 patients examined, 195 sites were sampled, including 145 diseased ones. Trichomonads were only observed on 16 of the 145 diseased sites (11%) and none in the other 50 healthy sites. Based on these results, 20% (n = 10) of patients were positive for the presence of trichomonads from at least one of the diseased sites collected. Tooth mobility, substantial supra-gingival dental deposits, and severe clinical attachment loss were statistically associated with trichomonad presence. If the subgingival biofilm of male patients over the age of 50 seemed to be more frequently contaminated with trichomonads, this data was not statistically supported. This preliminary study indicates for the first time that in periodontitis-involved patients, trichomonads are observed in the subgingival biofilm collected from diseased sites with severe bone loss, but not from healthy teeth. Further investigations are needed to fully explore the role of this microorganism in the etiology of periodontal disease.

Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells

BACKGROUND

Trichomonas vaginalis is the aetiological agent of human trichomoniasis, which is one of the most prevalent sexually transmitted diseases in humans. Iron is an important element for the survival of this parasite and the colonisation of the host urogenital tract.

OBJECTIVES

In this study, we investigated the effects of iron on parasite proliferation in the dynamics of pseudocyst formation and morphologically characterised iron depletion-induced pseudocysts.

METHODS

We performed structural and ultrastructural analyses using light microscopy, scanning electron microscopy and transmission electron microscopy.

FINDINGS

It was observed that iron depletion (i) interrupts the proliferation of T. vaginalis, (ii) induces morphological changes in typical multiplicative trophozoites to spherical non-proliferative, non-motile pseudocysts, and (iii) induces the arrest of cell division at different stages of the cell cycle; (iv) iron is the fundamental element for the maintenance of typical trophozoite morphology; (v) pseudocysts induced by iron depletion are viable and reversible forms; and, finally, (vi) we demonstrated that pseudocysts induced by iron depletion are able to interact with human epithelial cells maintaining their spherical forms.

MAIN CONCLUSIONS

Together, these data suggest that pseudocysts could be induced as a response to iron nutritional stress and could have a potential role in the transmission and infection of T. vaginalis.

FunctionAnnotator, a versatile and efficient web tool for non-model organism annotation

Along with the constant improvement in high-throughput sequencing technology, an increasing number of transcriptome sequencing projects are carried out in organisms without decoded genome information and even on environmental biological samples. To study the biological functions of novel transcripts, the very first task is to identify their potential functions. We present a web-based annotation tool, FunctionAnnotator, which offers comprehensive annotations, including GO term assignment, enzyme annotation, domain/motif identification and predictions for subcellular localization. To accelerate the annotation process, we have optimized the computation processes and used parallel computing for all annotation steps. Moreover, FunctionAnnotator is designed to be versatile, and it generates a variety of useful outputs for facilitating other analyses. Here, we demonstrate how FunctionAnnotator can be helpful in annotating non-model organisms. We further illustrate that FunctionAnnotator can estimate the taxonomic composition of environmental samples and assist in the identification of novel proteins by combining RNA-Seq data with proteomics technology. In summary, FunctionAnnotator can efficiently annotate transcriptomes and greatly benefits studies focusing on non-model organisms or metatranscriptomes. FunctionAnnotator, a comprehensive annotation web-service tool, is freely available online at: http://fa.cgu.edu.tw/. This new web-based annotator will shed light on field studies involving organisms without a reference genome.

Trichomonas tenax and periodontal diseases: a concise review

Periodontal diseases (gingivitis and periodontitis), result from a disruption of the host-oral microbiome homoeostasis. Whereas the pathological role of some specific bacterial strains during periodontal diseases is well documented, the impact of parasites in periodontium pathophysiology is still under debate. This review aims to collect data about the prevalence and the potential role of Trichomonas tenax during periodontal diseases. Data from 47 studies revealed that T. tenax prevalence in diseased periodontium ranged from 0 to 94·1%. The prevalence of oral protozoan infections was found to be largely greater in patients with periodontal diseases than with healthy periodontium. The parasite detection was mainly performed by direct microscopy. Trichomonas tenax presence was clearly correlated with periodontal disease. The high heterogeneity of its periodontal prevalence may be correlated with the diversity of the population screened (age, sex, systemic diseases), and the methods used for diagnosis. This protozoan seems to have the capacity to be involved in the inflammatory process of gum disease. Animal experimentation, using relevant physiopathological models of periodontitis, needs to be performed to investigate the ability of T. tenax to cause and/or worsen the disease. Further investigations using standardized experimental designs of epidemiologic studies are also needed.

Zoonotic Trichomonas tenax and a new trichomonad species, Trichomonas brixi n. sp., from the oral cavities of dogs and cats

Trichomonads are known to inhabit the oral cavities of various mammals, including dogs, cats and horses. However, little attention has been paid to species identification, prevalence and zoonotic potential of these parasites, although their hosts live in close proximity with humans. According to the original description, oral trichomonads in dogs and cats belong to the genus Tetratrichomonas. Interestingly, later investigations suggested that the oral cavities of dogs and cats could be infected with different species of the genus Trichomonas, including the human oral cavity parasite Trichomonas tenax. Thus, in this study we investigated the occurrence of oral trichomonads in 111 domestic dogs and 122 cats using cell cultivation methods, nested PCR analyses, and the sequencing of ITS1-5.8rRNA-ITS2 regions. We found that both dogs and cats harbour T. tenax, with prevalences of 8.1% and 4.1%, respectively. Considerably more dogs were infected with different species of the genus Trichomonas (30.6%), which we also identified in cats (6.6%). An analysis of the potential risk factors suggested that dogs of more than 3years old or with dental disease signs are more frequently infected with Trichomonas sp. than younger dogs or dogs without the disease signs, and that crossbreed dogs revealed increased rates of infection in comparison with purebred dogs. An analysis of the cat population suggested that Trichomonas sp. infection is lower in younger and crossbreed cats. Although the morphology of Trichomonas sp. is very similar to that of T. tenax, based on a phylogenetic analysis of ITS1-5.8rRNA-ITS2 regions and the ssrRNA genes, we consider Trichomonas sp. to represent a new trichomonad species, for which we propose the name Trichomonas brixi.

The Prevalence of Canine Oral Protozoa and Their Association with Periodontal Disease

Periodontal disease is one of the most important health concerns for companion animals. Research into canine forms of periodontitis has focused on the identification and characterization of the bacterial communities present. However, other microorganisms are known to inhabit the oral cavity and could also influence the disease process. A novel, broad spectrum 18S PCR was developed and used, in conjunction with next-generation sequencing analyses to target the identification of protists. Trichomonas sp. and Entamoeba sp. were identified from 92 samples of canine plaque. The overall prevalence of trichomonads was 56.52% (52/92) and entamoebae was 4.34% (4/92). Next-generation sequencing of pooled healthy, gingivitis, early-stage periodontitis, and severe periodontitis samples revealed the proportion of trichomonad sequences to be 3.51% (health), 2.84% (gingivitis), 6.07% (early periodontitis), and 35.04% (severe periodontitis), respectively, and entamoebae to be 0.01% (health), 0.01% (gingivitis), 0.80% (early-stage periodontitis), and 7.91% (severe periodontitis) respectively. Both genera of protists were statistically associated with plaque from dogs with periodontal disease. These findings provide the first conclusive evidence for the presence of oral protozoa in dog plaque and suggest a possible role for protozoa in the periodontal disease process.

Cytokine response of human THP-1 macrophages to Trichomonas tenax

Trichomonas tenax is a protozoan that inhabits the oral cavity of humans, most often those with poor oral hygiene. Although T. tenax is widely considered a commensal, recent studies have suggested a pathogenic role for the protozoan in persons with periodontitis. Here we investigated the capacity of T. tenax to induce pro-inflammatory cytokine secretion in human macrophages, with the idea that elicitation of inflammation may be one mechanism by which T. tenax contributes to oral pathology. Human THP-1 cells differentiated to the macrophage phenotype (dTHP-1) were incubated with live or sonicated T. tenax at trophozoite:dTHP-1 ratios of 1:5, 1:10, and 1:20. Culture media removed from the wells after 4, 8, and 16 h of stimulation were assayed by ELISA for tumor necrosis factor alpha, interleukin-1 beta, interleukin-8, and the immunoregulatory cytokine interleukin-10. Live T. tenax trophozoites failed to induce production of any of the cytokines tested, regardless of trophozoite:dTHP-1 cell ratio or length of co-incubation. T. tenax lysates stimulated interleukin-8 synthesis, but only after 16 h of incubation at the 1:5 trophozoite:dTHP-1 cell ratio. These results suggest that pro-inflammatory cytokine synthesis by human macrophages in direct response to T. tenax contributes little to oral pathology.

Bulky Trichomonad Genomes: Encoding a Swiss Army Knife

The trichomonads are a remarkably successful lineage of ancient, predominantly parasitic protozoa. Recent molecular analyses have revealed extensive duplication of certain genetic loci in trichomonads. Consequently, their genomes are exceptionally large compared to other parasitic protozoa. Retention of these large gene expansions across different trichomonad families raises the question: do these duplications afford an advantage? Many duplicated genes are linked to the parasitic lifestyle and some are regulated differently to their paralogues, suggesting they have acquired new functions. It is proposed that these large genomes encode a Swiss army knife of sorts, packed with a multitude of tools for use in many different circumstances. This may have bestowed trichomonads with the extraordinary versatility that has undoubtedly contributed to their success.

Iron-modulated pseudocyst formation inTritrichomonas foetus

Iron is an essential element for the survival of trichomonads during host–parasite interaction. The availability of this metal modulates several metabolic pathways of the parasites and regulates the expression of virulence factors such as adhesins and proteolytic enzymes. In this study, we investigated the effect of iron depletion on the morphology and life cycle ofTritrichomonas foetus. Scanning and transmission electron microscopy analyses revealed that depletion of iron from the culture medium (named TYM-DIP inducer medium) induces morphological transformation of typical pear-shaped trophozoites into spherical and non-motile pseudocysts. Remarkably, inoculation of pseudocysts into an iron-rich medium (standard TYM medium), or addition of FeSO4to a TYM-DIP inducer medium reverted the morphological transformation process and typical trophozoites were recovered. These results show that pseudocysts are viable forms of the parasite and highlight the role of iron as a modulator of the parasite phenotype. Although iron is required for the survival ofT. foetus, iron depletion does not cause a cellular collapse of pseudocysts, but instead induces phenotypic alterations, probably in order to allow the parasite to survive conditions of nutritional stress. Together, these findings support previous studies that suggest pseudocysts are a resistance form in the life cycle ofT. foetusand enable new approaches to understanding the multifactorial role of iron in the cell biology of this protozoan parasite.

Canine Trichomonas tenax mandibular gland infestation

Background

Several species of trichomonads are intestinal or urogenital parasites of humans and animals, with only a few species typically being located in the oral cavity. The prevalence of oral trichomoniasis in dogs is approximately 15–25 %, although the prevalence varies among different populations and depends on age, sex and the health of the oral cavity.

Case presentation

A case of mandibular gland infestation by trichomonads in a 13-year-old female Dachshund with advanced periodontal disease and oral trichomoniasis is reported. The dog was referred due to a history of a painless swelling over the left submandibular region that increased in size over time. Based on physical and ultrasound examinations, a final diagnosis of mandibular gland cyst was established and transcutaneous needle aspiration was carried out. Numerous mobile trophozoites of trichomonads were found by microscopy and culturing for trichomonas was performed. The species was finally characterized as Trichomonas tenax by polymerase chain reaction and sequencing.

Conclusions

Studies have shown that T. tenax can be found in humans in atypical locations such as the salivary glands and upper and lower respiratory tracts. According to our knowledge this is the first report of T. tenax being present in the salivary glands of a dog. Because of the relatively high prevalence of trichomoniasis in dogs with periodontal diseases, these parasites should be considered together with bacterial and viral agents in salivary gland infections, especially in individuals with compromised oral health.

Observation of trichomonads infection in a child with periodontitis by direct microscopy at the dental office

The pathogenicity of Trichomonas species is well documented. Although their exact involvement in gum disease is not fully understood, recent studies suggest a correlation between these protozoa and periodontitis. This case report details the first chair-side observation in Europe of an oral trichomonad infection in a child with periodontitis, by direct microscopy. The dramatic recovery of the patient, observed following administration of an anti-parasitic treatment, confirms the necessity of further investigation in this field.