Growth kinetics, antigen profiling, and proteinase activity of Egyptian Trichomonas tenax isolates derived from patients having oral infections

Risk factors and approaches for detection of Trichomonas tenax, the silent culprit in periodontal disease: A narrative review

Introduction

Periodontal disease is the inflammation of the periodontium tissues surrounding the teeth, potentially leading to loss of tooth attachment. In individuals with periodontal disease, the presence of Trichomonas tenax, a parasitic protozoan of the oral cavity has been observed and its frequency tends to rise as the disease progresses.

Methods

A literature search was conducted in the online databases of PubMed, Google Scholar, Web of Science, and Scopus using the combination of keywords: "Trichomonas tenax" AND "periodontal disease" OR "gum disease", OR "oral disease" OR "periodontitis". A total of 9 articles satisfied the inclusion criteria and were included in this study.

Results

This review highlights the incidence of T. tenax with periodontal diseases, the risk factors that contribute to the infection of T. tenax and available detection methods for the identification of the protozoan.

Conclusion

The inhabitation of the oral cavity by T. tenax prospers with the severity of periodontal diseases. Extensive research should be conducted to fully understand the potential pathogenic role and damaging effect of T. tenax in the oral cavity.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Prevalence of Oral Trichomonas tenax in Periodontal Lesions of Down Syndrome in Tabriz, Iran

BACKGROUND

It was presented that Trichomonas tenax is one of the parasites which is responsible for oral infection. This study was considered to estimate the prevalence of this parasite in oral cavity of Down syndrome patients with periodontal lesions and in healthy population from welfare organization in Tabriz, Iran.

MATERIALS AND METHODS

In the case-control study, 52 patients with periodontal disease (case group) and 52 individuals with healthy gingiva (control group) selected for the study. Examination was done by dental mirror and periodontal probe. After using plaque detector tablets, sampling was done by entering sterile paper into periodontal pocket for 20 seconds. The amount of plaque was measured by plaque index. Finally samples sent to laboratory for prepared PCR reaction.

RESULTS

In the case group, 14 patients were infected and in the control group 5 individuals. Percentage of infection in case group was 18.8% and in the control group was 3% that difference was statically significant. Plaque index in the case group was 72 ± 10.2 and in the control group was 68 ± 11.4 and difference between two groups was not significant.

CONCLUSION

Parasitic infections in Down syndrome were higher than healthy children while plaque index was not significantly different between the two groups. Therefore follow-up of orders are necessary in control of parasitic infection in Down syndrome that have intrinsic defect of immune systems.

The Transcriptome Sequence of Dientamoeba fragilis Offers New Biological Insights on its Metabolism, Kinome, Degradome and Potential Mechanisms of Pathogenicity

Dientamoeba fragilis is a human bowel parasite with a worldwide distribution. Dientamoeba was once described as a rare and harmless commensal though recent reports suggest it is common and potentially pathogenic. Molecular data on Dientamoeba is scarce which limits our understanding of this parasite. To address this, sequencing of the Dientamoeba transcriptome was performed. Messenger RNA was extracted from cultured Dientamoeba trophozoites originating from clinical stool specimens, and sequenced using Roche GS FLX and Illumina HiSeq technologies. In total 6,595 Dientamoeba transcripts were identified. These sequences were analysed using the BLAST2GO software suite and via BLAST comparisons to sequences available from TrichDB, GenBank, MEROPS and kinase.com. Several novel KEGG pathway maps were generated and gene ontology analysis was also performed. These results are thoroughly discussed guided by knowledge available for other related protozoa. Attention is paid to the novel biological insights afforded by this data including peptidases and kinases of Dientamoeba, as well as its metabolism, novel chemotherapeutics and possible mechanisms of pathogenicity. Currently, this work represents the largest contribution to our understanding of Dientamoeba molecular biology and also represents a major contribution to our understanding of the trichomonads generally, many of which are important pathogens of humans and animals.

Is Trichomonas tenax a Parasite or a Commensal?

Trichomonas tenax is considered a commensal organism found under poor oral hygiene conditions. T. tenax presents morphological similarities with T. vaginalis, and there are doubts concerning whether this protist is a parasite and whether it is a genetic variant of T. vaginalis. This study aimed to investigate the capacity of T. tenax to cause mammalian cell damage and compare its cytotoxicity with that of T. vaginalis. Protozoan-host cell interaction assays were performed with Madin-Darby canine kidney, HeLa, and gum cells and 3D spheroids, which were examined by scanning electron and transmission electron microscopy. Cellular viability experiments were also performed. T. tenax attached and had different forms when interacting with mammalian cells and caused damage with time-dependent host-cell viability. We observed that T. tenax produced plasma membrane projections and phagocytosed portions of the mammalian cells. In addition, T. tenax caused membrane blebbing and apoptotic bodies in HeLa cells, thus inducing cell death. Spheroids were also used in interaction assays with T. tenax and they were damaged by these cells. This study shows that T. tenax fulfills the requisites of a parasite, causing damage to different mammalian cells and behaving similarly to T. vaginalis when in contact with target cells in vitro.