Detection of the amoeba Entamoeba gingivalis in periodontal pockets

Prevalence, socio-economic, and associated risk factors of oral cavity parasites in children with intellectual disability from Lorestan province, Iran

Introduction

Children with intellectual disability (ID) often face challenges in maintaining proper oral hygiene due to their motor, sensory, and intellectual impairments, which can lead to compromised oral health; therefore, there is a need to enhance the oral health status of these populations and establish an effective system for administering preventive interventions. Here, we aimed to evaluate the prevalence of Entamoeba gingivalis and Trichomonas tenax among children with ID in Lorestan province, in Western Iran through parasitological and molecular methods.

Methods

The current descriptive investigation involved 215 in children with ID and 215 healthy children (non-ID) who were referred to health facilities in Lorestan province, Iran between October 2022 and March 2024. The prevalence of protozoa in the oral cavity was found through the utilization of both microscopic analysis and conventional polymerase chain reaction (PCR) techniques.

Results

The total prevalence of the E. gingivalis and T. tenax in children with ID was found to be 87 (40.5%) and 92 (42.8%) through microscopic and PCR methods, respectively. Among the positive samples, 57 (61.9%) and 35 (38.1%) children tested positive for E. gingivalis and T. tenax, respectively. In contrast, among the 215 non-ID children in the control group, 39 (18.1%) and 42 (19.5%) tested positive by microscopic and PCR methods, respectively. Among positive samples in non-ID children, 23 (54.7%) and 19 (45.3%) children were positive for E. gingivalis and T. tenax, respectively. Multiple logistic regression analysis indicated that residing in urban areas, parental education, monthly family income, and tooth brushing p<0.001) were identified as independent risk factors for oral cavity parasites.

Conclusion

This study identified a notable prevalence of oral cavity parasites in children with ID in Lorestan province, Western Iran. It is imperative to recognize the primary risk factors associated with these parasites, particularly inadequate teeth brushing, in order to enhance public and oral health strategies for children with ID. Therefore, pediatric dental professionals should remain vigilant regarding these risk factors to effectively recognize and address oral health issues in this population, thereby mitigating the occurrence of oral diseases and infections.

Association of Entamoeba gingivalis with Periodontal Disease-Systematic Review and Meta-Analysis

The oral cavity is a habitat to a diverse range of organisms that make up an essential element of the human microbiota. There are up to 1000 species of micro-organisms capable of colonizing the mouth. Thirty percent of them are uncultivable. The genus Entamoeba includes several species, out of which at least seven of them are able to inhabit the human body (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coli, Entamoeba polecki, Entamoeba hartmann, Entamoeba gingivalis). It was shown that only E. gingivalis is able to colonize the oral cavity. The aim of this study was to evaluate the association and prevalence of E. gingivalis in periodontal disease using two electronic database search engines. In order to have a broader view of the subject, a comprehensive manual search was conducted between 15th February 2023 and 1 April 2023 on these content aggregators and the initial search resulted in 277 articles using the keywords "E. gingivalis", "periodontitis", "E. gingivalis", "periodontal disease", "prevalence", and "incidence", in different combinations. The results showed that 755 patients were infected with E. gingivalis out of a total number of 1729 patients diagnosed with periodontal disease, indicating a global prevalence of 43% in the set of patients analyzed. E. gingivalis was prevalent in 58% of the patients that had gingivitis and in 44% of the patients with periodontitis. Prevalence of E. gingivalis based on gender was 43% in female patients and 47% in male patients. The results indicate that the higher incidence of E. gingivalis in people with periodontal disease compared to healthy people is more than just a sign of the disease; it could also be linked to the severity of the condition and the disease propensity to progress.

In vitro induction of Entamoeba gingivalis cyst-like structures from trophozoites in response to antibiotic treatment

Background

Entamoeba gingivalis (E. gingivalis) is an anaerobic protozoan that is strongly associated with inflamed periodontal pockets. It is able to invade the mucosal epithelium of the human host, where it can feed on epithelial cells and elicit a severe innate immune response. Unlike other Entamoeba species, it is considered that E. gingivalis cannot form cysts, because it is a non-infectious protozoan. The lack of encystation capability would make it susceptible to periodontal treatment. However, it is not clear how the human host becomes infected with E. gingivalis trophozoites. We investigated the ability of E. gingivalis to encapsulate in response to an unfavorable environment in vitro.

Methods

Different strains of E. gingivalis, isolated from inflamed periodontal pocket samples, were cultured for 8 days in the presence or absence of the antimicrobials amoxycillin and metronidazole. To reveal cyst formation, we investigated the morphology and ultrastructure of the amoeba by light, fluorescence, transmission and scanning electron microscopy. We also used the fluorescent dye calcofluor white M2R to demonstrate chitin present in the cyst wall.

Results

We observed exocysts and an intra-cystic space separating the encapsulated trophozoite from the environment. Remarkably, cysts showed a smooth surface, polygonal edges and smaller size compared to free-living trophozoites. In addition, encapsulated trophozoites that detached from the cyst wall had a dense cytoplasma without phagocytic vesicles. The cyst walls consisted of chitin as in other Entamoba species. The encapsulated trophozoids were mononuclear after antibioticinduced encapsulation.

Discussion

We conclude that E. gingivalis cyst formation has significant implications for dissemination and infection and may explain why established treatment approaches often fail to halt periodontal tissue destruction during periodontitis and peri-implantitis.

Molecular Epidemiology and Associated Risk Factors of Parasites in Oral Cavity of Children with Malignancies in Western Iran

Background

This survey was designed to study the molecular epidemiology and risk factors of Entamoeba gingivalis and Trichomonas tenax in children with underlying malignancies and those on chemotherapy in Lorestan province, West of Iran.

Methods

The present cross-sectional descriptive study was performed on children who suffering from different types of malignancies or receiving treatment by chemotherapy referring to oncology section of hospitals of Lorestan Province, Iran during May 2021 to April 2022. The frequency of oral cavity protozoa was investigated using microscopic and conventional polymerase chain reaction (PCR).

Results

E. gingivalis and T. tenax parasites were found in 23 (25.5%) by microscopic method and 28 (31.1%) using PCR in children with malignancy. Among positive samples, 20 (71.4%) were infected with E. gingivalis; whereas 8 (28.6%) of the participants were positive for T. tenax. In the multivariate model, living in rural regions (OR= 3.437; 95% CI= 1.22-9.63; p=0.019) and using mouthwash (OR= 0.082; 95% CI= 0.018-0.37; p<0.001) were significantly related with the frequency of oral cavity parasites.

Conclusion

Our results showed the high frequency of oral cavity parasites in children who suffering malignancies or receiving treatment by chemotherapy in Lorestan province, Iran. The awareness of the main risk factors for oral cavity parasites particularly using mouthwash is necessary in improving public and oral health strategies in children with cancer. Consequently, oncologist and dental practitioners must be aware to identify and manage oral health concerns in in children who suffering from different types of malignancies to prevent the oral diseases and infections.

Prevalence of Entamoeba gingivalis and Trichomonas tenax among patients with periodontal disease attending Dental Clinic, University College Hospital, Ibadan

Background

Periodontal disease is often caused by bacterial plaque. However, there are indications that some infective agents, including parasites, may play important roles in the pathogenesis of the disease.

Aim

This study aimed at assessing the prevalence of gingivitis and periodontitis, as well as the prevalence of Entamoeba gingivalis and Trichomonas tenax, in the oral biofilm of individuals with periodontal diseases using polymerase chain reaction.

Materials and Methods

One hundred and six respondents with periodontal disease participated in the study. All study participants had a full-mouth examination, and dental plaque samples were collected with a sterile curette. Samples were transported to the laboratory in a cold chain and stored frozen till analyzed. DNA was extracted from the samples and amplified using EGO and ENTAM primers for Entamoeba and TGBK primers for T. tenax.

Results

The mean age of respondents was 45 ± 16.3 years, with none using tobacco. The prevalence of gingivitis and periodontitis obtained from this study was 84.9% and 15.1%. The prevalence obtained for Entamoeba and T. tenax was 0.9% each; however, no participant had both parasites. The positive samples were from male participants with moderate gingivitis.

Conclusion

Gingivitis was more prevalent than periodontitis, though with a high preponderance in females. E. gingivalis and T. tenax may not be of etiologic importance in periodontal disease as they occurred sparsely in the studied population.

Pilot Study on the Prevalence of Entamoeba gingivalis in Austria-Detection of a New Genetic Variant

Entamoeba gingivalis is a parasitic protist that resides in the oral cavity. Although E. gingivalis has been frequently detected in individuals with periodontitis, its precise role in this context remains to be established, since E. gingivalis is also regularly found in healthy individuals. Sequence data on E. gingivalis are still scarce, with only a limited number of sequences available in public databases. In this study, a diagnostic PCR protocol was established in order to obtain a first impression on the prevalence of E. gingivalis in Austria and enable a differentiation of isolates by targeting the variable internal transcribed spacer regions. In total, 59 voluntary participants were screened for E. gingivalis and almost 50% of the participants were positive, with a significantly higher prevalence of participants with self-reported gingivitis. Moreover, in addition to the established subtypes ST1 and ST2, a potentially new subtype was found, designated ST3. 18S DNA sequencing and phylogenetic analyses clearly supported a separate position of ST3. Interestingly, subtype-specific PCRs revealed that, in contrast to ST2, ST3 only occurred in association with ST1. ST2 and ST1/ST3 were more often associated with gingivitis; however, more data will be necessary to corroborate this observation.

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.

Molecular epidemiology and associated risk factors of oral cavity parasites in hemodialysis patients in western Iran

Renal disorders are able to make patients more susceptible to infections, including those caused oral cavity infections. Today, it has been proven that during end stage renal failure, hemodialysis results in acquired immune response defects through failings of humoral and cell-mediated immune. This survey was intended to assess the molecular epidemiology and associated risk factors of Entamoeba gingivalis and Trichomonas tenax as the main oral cavity protozoa in hemodialysis patients in Lorestan Province, western Iran. The investigation was performed on 73 hemodialysis patients referring to hemodialysis centers of Lorestan Province, Iran during May 2021 to February 2022. The frequency of oral cavity protozoa was investigated using microscopic and conventional polymerase chain reaction (PCR). A provided questionnaire with a number of demographical information and related risk factors was completed for each patient. The results showed that E. gingivalis and T. tenax parasites were found in 18 (24.6%) and 20 (27.4%) of the hemodialysis participants by microscopic and PCR test, respectively. Among samples, 13 (17.8%) of the hemodialysis participants were infected with E. gingivalis; whereas 7 (9.6%) of the participants were positive for T. tenax. No significant association was reported between gender, age, education, flossing, use of mouthwash, and prevalence of oral protozoa in hemodialysis participants. However, a significant correlation was observed among between living in rural regions (OR = 13.16; 95% CI = 2.64-56.81; p = 0.002), brushing teeth (OR = 8.51; 95% CI = 1.71-42.3; p = 0.009) and prevalence of oral protozoa in hemodialysis participants. The findings of these epidemiological study clearly showed the high frequency of oral cavity parasites in hemodialysis patients in Lorestan Province, Western Iran. Awareness of the main risk factors for oral cavity parasites particularly teeth brushing is necessary in refining public and oral health policies in hemodialysis patients. Consequently, dental practitioners, nephrologist, and urologist must be alert of these risk factors to carefully identify and achieve oral health concerns in hemodialysis patients to prevent the oral diseases and infections.

First molecular detection of Entamoeba gingivalis subtypes in individuals from Turkey

Entamoeba gingivalis is a parasitic protozoan that colonizes the human oral cavity and there are two subtypes (ST1 and ST2) that have been identified to date. However, there are no reports on the molecular detection or characterization of E. gingivalis in Turkey. The objective of this study was to detect the presence of E. gingivalis in Turkish healthy individuals and those with periodontal disease and to subtype the isolates using molecular techniques. Samples from the oral cavity of 94 individuals were taken and the presence of E. gingivalis was determined by PCR using primers for SsrRNA and the amplicons were then confirmed by DNA sequencing. Each participant completed a questionnaire that included demographic data, habits and lifestyle, as well as health status. The presence of E. gingivalis was detected in a total of 19 samples (11 patients and eight healthy individuals). Molecular characterization determined that 12 samples belonged to ST1 and seven samples belonged to ST2. The presence of E. gingivalis was higher in patients with periodontal disease than in healthy individuals, and this association was statistically significant (P < .05). This study constitutes the first report of molecular detection and subtyping of E. gingivalis in Turkey.

Widespread, human-associated redondoviruses infect the commensal protozoan Entamoeba gingivalis

Redondoviruses are circular Rep-encoding single-stranded DNA (CRESS) viruses of high prevalence in healthy humans. Redondovirus abundance is increased in oro-respiratory samples from individuals with periodontitis, acute illness, and severe COVID-19. We investigated potential host cells supporting redondovirus replication in oro-respiratory samples and uncovered the oral amoeba Entamoeba gingivalis as a likely host. Redondoviruses are closely related to viruses of Entamoeba and contain reduced GC nucleotide content, consistent with Entamoeba hosts. Redondovirus and E. gingivalis co-occur in metagenomic data from oral disease and healthy human cohorts. When grown in xenic cultures with feeder bacteria, E. gingivalis was robustly positive for redondovirus RNA and DNA. A DNA proximity-ligation assay (Hi-C) on xenic culture cells showed enriched cross-linking of redondovirus and Entamoeba DNA, supporting E. gingivalis as the redondovirus host. While bacteria are established hosts for bacteriophages within the human virome, this work shows that eukaryotic commensals also contribute an abundant human-associated virus.

Entamoeba gingivalis is associated with periodontal conditions in Chinese young patients: A cross-sectional study

Background

This study investigated the prevalence and relative abundance of Entamoeba gingivalis (E. gingivalis) in Chinese young patients with different periodontal conditions, and its association with subgingival microbial composition, periodontal parameters, and cytokines in gingival crevicular fluid.

Methods

Participants (age: 18–45 years) diagnosed with stage II–IV periodontitis, gingivitis, or periodontal health underwent periodontal examination and sampling. Subgingival plaque was analyzed by 16S+18S sequencing for E. gingivalis detection and microbial analysis. The distribution of E. gingivalis in subgingival plaque was illustrated by fluorescence in situ hybridization. Interleukin-1β, interleukin-8, and tumor necrosis factor-α in gingival crevicular fluid were measured by multiplexed flow cytometric assay.

Results

This cross-sectional study included 120 sites from 60 participants. The prevalence and relative abundance of E. gingivalis were significantly increased in periodontitis (p<0.05). The sites were classified into three subgroups according to the relative abundance of E. gingivalis: negative group (Eg0, n=56); low-abundance group (Eg1, n=32); and high-abundance group (Eg2, n=32). The subgingival microflora in the subgroups showed stepwise changes at both the phylum and genus levels. The microflora compositions were significantly altered from Eg0 to Eg2 (p<0.001). Co-occurrence network analysis showed that Porphyromonas, Treponema, Tannerella, Filifactor, TG5, and Desulfobulbus were highly correlated with E. gingivalis (r>0.6, p<0.001). Correlation analysis showed that E. gingivalis was closely associated with important periodontal parameters and cytokines (p<0.01).

Conclusion

E. gingivalis was enriched in periodontitis and closely associated with subgingival microbial dysbiosis, periodontal parameters and cytokines in gingival crevicular fluid. Thus, it may be an important pathogen in periodontal disease.

Assessment of Entamoeba gingivalis and Trichomonas tenax in Patients with Chronic Diseases and its Correlation with Some Risk Factors

Trichomonas tenax (T. tenax) and Entamoeba gingivalis (E. gingivalis) are two oral protozoan parasites that are universal and found in patients with poor oral hygiene, as well as chronic and periodontal diseases. This study was conducted to assess the efficacy of some parameters, such as age, gender, education, residency, smoking, and dental cleaning routines, on the incidence of these parasites in the oral cavity of the patients participating in this study. A total of 230 individuals with chronic diseases, 97 of whom were patients (44 females and 53 males) participated in the present study. Dental plaque and saliva samples were collected from each patient and examined under light microscopy with Giemsa staining. Out of 230 dental plaque samples, 60 (26.08%) samples were positive for E. gingivalis, while 37 (16.08%) cases were positive for T. tenax. Diabetic patients showed high E. gingivalis percentage (n=12; 20%) (P=0.000*). However, thyroid disorders showed a low percentage. Hypertensive patients showed a high percentage for T. tenax (n=6; 16.21%) (P=0.000*), while tuberculosis patients showed the lowest percentage. Patients with hypertension, smoking, heart disease, and diabetes showed statistical significance for the presence of these parasites. Equally, patients older than 30 years have shown a higher rate of infection. According to the findings, E. gingivalis was detected in 58.33% and 41.66% of the urban and rural populations, respectively. Furthermore, T. tenax was detected in 81.08% and 18.91% of the urban and rural populations, respectively. Parasitic contagions were comparatively popular in patients with chronic and periodontal illness.

Structural and Genetic Diversity of Entamoeba gingivalis Trophozoites Isolated from Diseased and Healthy Periodontal Sites

BACKGROUND: At present, there is little documented about the variability aspects of Entamoeba gingivalis (E. gingivalis) in relation to periodontal diseases. This is perhaps due to several specialists rejecting the notion that E. gingivalis can cause periodontal disease. AIM: The aim of the present study was to compare the morphological and genetic variability within trophozoites isolated from diseased (n = 26) and healthy periodontal sites (n = 14). METHODS: Detailed microscopic analyses were performed, in addition to post real-time polymerase chain reaction 18S-SSU rRNA gene scanning technology, using reference synthetic genes to analyze melting curve features from different isolates. RESULTS: All trophozoites isolated from diseased sites were significantly larger in size than those isolated from healthy sites. In addition, they were found in clusters, containing many leukophagocytosis and in a significantly higher number than those from healthy sites. Gene scanning revealed diversity within the isolates with a significantly higher number of mutant forms (18 out of 26) within the trophozoites isolated from diseased sites, 14 of them were of unknown origin. Four melting curves matched E. gingivalis H57 strain and the remaining eight were related to the wild strain (ATCC-30927). Isolates from healthy sites corresponded to the wild type (12 out of 14) with only two related to H57 strain. CONCLUSION: The study confirmed morphological and genetic variability between different isolates; We still recommend further in-depth molecular studies to investigate the role of this oral protozoan in the pathogenicity of periodontal affection. The study highlighted the importance of real engagement of multidisciplinary diagnostic strategies, involving experts from variable medical fields to reach truthful scientific outcomes concerning the association of certain microorganism to particular diseases or disorders.

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.

Oral Colonization by Entamoeba gingivalis and Trichomonas tenax: A PCR-Based Study in Health, Gingivitis, and Periodontitis

Background

The etiology of periodontitis remains unclear, as is the place of gingivitis in its pathophysiology. A few studies linked the colonization by oral parasites (Entamoeba gingivalis and Trichomonas tenax) to periodontal disease and its severity. The aim of the current study was to estimate the prevalence of these oral parasites among healthy individuals, and in patients with gingivitis and periodontitis in Jordan.

Methods

The study was conducted during July 2019–December 2019. Samples were composed of saliva and periodontal material including dental plaque sampled with probes. The detection of oral parasites was done using conventional polymerase chain reaction (PCR).

Results

The total number of study participants was 237: healthy (n=94), gingivitis (n=53) and periodontitis (n=90). The prevalence of E. gingivalis was 88.9% among the periodontitis patients, 84.9% among the gingivitis patients and 47.9% in the healthy group. For T. tenax, the prevalence was 25.6% among the periodontitis patients, 5.7% among the gingivitis patients and 3.2% in the heathy group. Positivity for E. gingivalis was significantly correlated with the presence of periodontal disease compared to the healthy group with odds ratio (OR) of 6.6. Periodontal disease was also correlated with lower monthly income (OR=8.2), lack of dental care (OR=4.8), and history of diabetes mellitus (OR=4.5). Colonization by E. gingivalis was correlated with gingivitis (OR=6.1) compared to the healthy group. Colonization by E. gingivalis and T. tenax were significantly correlated with periodontitis (OR=6.4 for E. gingivalis, and OR=4.7, for T. tenax) compared to the healthy group. T. tenax was only detected among individuals with generalized periodontal disease compared to its total absence among those with localized disease (19.6% vs. 0.0%; p=0.039). The co-infection rate by the two oral parasites was 11.0%.

Conclusions

The higher prevalence of human oral parasites in periodontal disease compared to healthy individuals appears to be more than a mere marker for the disease and might also be associated with disease severity and potential for progression. Thus, the dogmatic view of E. gingivalis and T. tenax as commensals needs to be re-evaluated and their contribution to pathophysiology of periodontal diseases cannot be neglected.

Current Global Status and the Epidemiology of Entamoeba gingivalis in Humans: A Systematic Review and Meta-analysis

PURPOSE

Entamoeba gingivalis (E. gingivalis) is one of the members of the wide range of oral resident pathogens in humans, particularly found in dental plaques, surfaces of gingiva or teeth, interdental spaces and carious lesions. The purpose of the current review and meta-analysis was to determine the global prevalence of E. gingivalis infection and its association with oral diseases based on published literatures.

MATERIALS AND METHODS

Multiple English databases (PubMed, Scopus, Science Direct, Web of Science and Google Scholar) were explored for papers published until August 2020. A total of 52 studies (including 7596 participants) met the inclusion criteria.

RESULTS

The overall prevalence of E. gingivalis was estimated to be 37% (95% CI 29-46%). With regard to different countries, the highest and lowest pooled prevalence of E. gingivalis infection were related to Jordan with 87% (95% CI 81-92%) and Portugal with 3% (95% CI 0-10%), respectively. Based on WHO regions, the highest prevalence was related to the region of the Americas with 56% (95% CI 31-79%). The infection was most prevalent in 46-55 mean age groups [61% (95% CI 21-94%)]. Among different diagnostic methods, the highest rate of the pooled prevalence was related to the molecular [53% (95% CI 24-81%)] and the direct methods [36% (95% CI 25-47%)], respectively. Our analyses revealed that E. gingivalis infection was associated with 4.34-fold increased risk of oral diseases (P < 0.05).

CONCLUSION

Our findings revealed a high prevalence rate of the infection among periodontal disease patients with 37% (95% CI 20-57%). To conclude, it must be considered that E. gingivalis can be a risk factor associated with oral diseases and a wide range of research is needed to specify its role in the pathogenesis of these disorders.

Entamoeba gingivalis: epidemiology, genetic diversity and association with oral microbiota signatures in North Eastern Tanzania

Background

Entamoeba gingivalis has been associated with periodontal diseases. Baseline data from the background population, which could help delimit the role of the parasite in health and disease, remain limited.

Objective

To describe epidemiological features, genetic diversity, and associations with oral microbiome signatures of E. gingivalis colonisation in Tanzanians with non-oral/non-dental diseases.

Methods

DNAs from 92 oral washings from 52 participants were subject to metabarcoding of ribosomal genes. DNA sequences were identified to genus level and submitted to oral microbiota diversity analyses.

Results

Sixteen (31%) of the 52 study participants were E. gingivalis-positive, with no difference in positivity rate according to gender or age. Only one subtype (ST1) was found. Individuals testing positive for E. gingivalis had higher oral microbiota alpha diversity than those testing negative (P = 0.03). Eight of the top-ten most common bacterial genera were shared between the two groups (Alloprevotella, Fusobacterium, Gemella, Haemophilus, Neisseria, Porphyromonas, Prevotella, Streptococcus, and Veillonella). Meanwhile, E. gingivalis carriers and non-carriers were more likely to have Aggregatibacter and Rothia, respectively, among the top-ten most common genera.

Conclusion

About one third of the cohort carried E. gingivalis ST1, and carriers had higher oral microbiome diversity and were more predominantly colonized by Aggregatibacter.

Entamoeba gingivalis Exerts Severe Pathogenic Effects on the Oral Mucosa

The protozoan Entamoeba gingivalis colonizes the healthy oral mucosa with a prevalence of 15%. Colonization can be asymptomatic, and it is considered not pathogenic. However, it is able to invade lacerated oral mucosa, where it ingests fragments of live cells, suggesting pathogenous potential. Here, we characterized the transcriptomes of gingival cells after infection with E. gingivalis using RNA sequencing and observed pathogen interaction with the epithelial monolayer barrier by scanning electron microscopy. In epithelial and fibroblast cells, strongest differential expression showed gene set “chemokines and inflammatory molecules in myeloid cells” (area under the curve [AUC] = 0.9, effect size 5.15, adjusted P = 3.1 × 10⁻¹⁹) and “cell cycle and growth arrest” (AUC = 0.91, effect size = 4.56, adjusted P = 4.8 × 10⁻⁹), respectively. The most upregulated genes were TNF (fold change 430) and IL8 (fold change 359) in epithelial cells and ZN331 (fold change 18) in fibroblasts. We showed that E. gingivalis killed live epithelial cells by trogocytosis, demonstrating strong pathogenic potential.

Acquisition and establishment of the oral microbiota

Acquisition and establishment of the oral microbiota occur in a dynamic process over various stages and involve close and continuous interactions with the host and its environment. In the present review, we discuss the stages of this process in chronological order. We start with the prenatal period and address the following questions: ‘Is the fetus exposed to maternal microbiota during pregnancy?’ and ‘If so, what is the potential role of this exposure?’ We comment on recent reports of finding bacterial DNA in placenta during pregnancies, and provide current views on the potential functions of prenatal microbial encounters. Next, we discuss the physiological adaptations that take place in the newborn during the birth process and the effect of this phase of life on the acquisition of the oral microbiota. Is it really just exposure to maternal vaginal microbes that results in the difference between vaginally and Cesarian section‐born infants? Then, we review the postnatal phase, in which we focus on transmission of microbes, the intraoral niche specificity, the effects of the host behavior and environment, as well as the role of genetic background of the host on shaping the oral microbial ecosystem. We discuss the changes in oral microbiota during the transition from deciduous to permanent dentition and during puberty. We also address the finite knowledge on colonization of the oral cavity by microbes other than the bacterial component. Finally, we identify the main outstanding questions that limit our understanding of the acquisition and establishment of a healthy microbiome at an individual level.

The Oral Parasitic Microbiome in Hepatitis B Virus Infected Sudanese Patients with Gum Disease

Background

We aimed to evaluate a potential link between colonization of gingival crevices by the Entamoeba gingivalis as oral parasite microbiome and Hepatitis B infection among gum disease Sudanese patients.

Methods

This study was conducted on 448 gum disease patients attending to Dental Clinic of Kosti Teaching Hospital, Kosti, Sudan in 2017-2018. Oral symptoms were registered in 336 patients at different stages of the HBV infection and in 112 HBV seronegative gum disease control. All participants were screened for HBV using ELISA test. Unstimulated whole saliva and gingival scraping were obtained and analyzed for the presence of the amoeba using a parasitological technique.

Results

Statistically highly significant correlation was found between the detection of the E. gingivalis in Saliva/gingival scraping and gum illness disease with HBV-infected patients than healthy control group (P<0.05). There was high association between the occurrence of the amoeba between the two groups and smoking, snuffing habitats (P<0.05), inversely, no association with the oral personal hygiene.

Conclusion

The presence of the amoeba was not related to the degree of gum diseases only, but to the HBV infection diagnosis. To our knowledge, this is the first study of E. gingivalis in association with HBV infection among gum disease Sudanese patients; maybe predict the role of oral parasitic microbiome in the status of gum disease in HBV infection.

Amoebae in Chronic, Polymicrobial Endodontic Infections Are Associated with Altered Microbial Communities of Increased Virulence

BACKGROUND

Infections of the root canal space involve polymicrobial biofilms and lead to chronic, low grade inflammatory responses arising from the seeding of microbes and by-products. Acute exacerbation and/or disseminating infections occur when established microbial communities undergo sudden changes in phenotypic behaviour.

METHODS

Within clinical endodontic infections, we assessedcategorical determinants comprising, and changing microbial composition of, chronic polymicrobial infections and their association with amoebae. After standardised assessment, primary or secondary infections underwent sampling and DNA processing, targeting bacteria, fungi and amoebae, including 16S high-throughput sequencing. After taxonomic assignment, community composition was correlated with clinical signs and symptoms. Diversity and abundance analyses were carried out in relation to the presence of non-bacterial amplicons.

RESULTS

Clinical specimens revealed two distinct community clusters, where specific changes correlated with clinical signs. An association between the compositions of microbiomes was found between these groups and the presence of Entamoeba gingivalis in 44% of cases. When amoebae were present in endodontic infections, we demonstrate changes in microbial community structure that mirror those observed in treatment-resistant or recurrent infections.

CONCLUSIONS

Amoeba are present in endodontic infections at a high prevalence, and may promote increased virulence by enrichment for phagocytosis-resistant bacteria.

Entamoeba gingivalis Causes Oral Inflammation and Tissue Destruction

A metagenomics analysis showed a strongly increased frequency of the protozoan Entamoeba gingivalis in inflamed periodontal pockets, where it contributed the second-most abundant rRNA after human rRNA. This observation and the close biological relationship to Entamoeba histolytica, which causes inflammation and tissue destruction in the colon of predisposed individuals, raised our concern about its putative role in the pathogenesis of periodontitis. Histochemical staining of gingival epithelium inflamed from generalized severe chronic periodontitis visualized the presence of E. gingivalis in conjunction with abundant neutrophils. We showed that on disruption of the epithelial barrier, E. gingivalis invaded gingival tissue, where it moved and fed on host cells. We validated the frequency of E. gingivalis in 158 patients with periodontitis and healthy controls by polymerase chain reaction and microscopy. In the cases, we detected the parasite in 77% of inflamed periodontal sites and 22% of healthy sites; 15% of healthy oral cavities were colonized by E. gingivalis. In primary gingival epithelial cells, we demonstrated by quantitative real-time polymerase chain reaction that infection with E. gingivalis but not with the oral bacterial pathogen Porphyromonas gingivalis strongly upregulated the inflammatory cytokine IL8 (1,900 fold, P = 2 × 10–4) and the epithelial barrier gene MUC21 (8-fold, P = 7 × 10–4). In gingival fibroblasts, we showed upregulation of the collagenase MMP13 (11-fold, P = 3 × 10–4). Direct contact of E. gingivalis to gingival epithelial cells inhibited cell proliferation. We indicated the strong virulence potential of E. gingivalis and showed that the mechanisms of tissue invasion and destruction are similar to the colonic protozoan parasite E. histolytica. In conjunction with abundant colonization of inflamed periodontal sites and the known resistance of Entamoeba species to neutrophils, antimicrobial peptides, and various antibiotics, our results raise the awareness of this protozoan as a potential and, to date, underrated microbial driver of destructive forms of periodontitis.

A brief history of periodontics in the United States of America: Pioneers and thought-leaders of the past, and current challenges

This paper summarizes historical events in periodontology in the United States over the past 200 years. The contributions of some of the key thought-leaders of the past are highlighted. Throughout the 20th century, the evolution of thought, leading to the views currently held regarding the pathogenesis and treatment of periodontal diseases, was significantly influenced by: (1) major changes in health-care education; (2) the emergence of periodontics as a specialty of dentistry; (3) the publication of peer-reviewed journals with an emphasis on periodontology; (4) formation of the National Institute of Dental and Craniofacial Research (NIDCR); and (5) expansion of periodontal research programs by the NIDCR. The two major future challenges facing periodontal research are development of a better understanding of the ecological complexities of host-microbial interactions in periodontal health and disease, and identification of the relevant mechanisms involved in the predictable regeneration of damaged periodontal tissues.

Protozoans in subgingival biofilm: clinical and bacterial associated factors and impact of scaling and root planing treatment

Objective: In patients with periodontitis, identification of protozoans and evaluation of some bacteria and clinical parameters associated and assessment of scaling and root planing (SRP) impact on their detection.

Methods: Before and after SRP, subgingival microbiota was collected in two pathological and one healthy site from 30 periodontitis patients. One healthy site from 30 control patients was also sampled. The usual clinical periodontal parameters were recorded; microbial detection was determined by PCR hybridization system for bacteria and qPCR for protozoans.

Results: In periodontitis group, Trichomonas tenax and two subtypes of Entamoeba gingivalis (ST1 and a variant ST2) were detected in respectively 33.3%, 70% and 18.3% of pathological samples, and in 6.7%, 10% and 3.3% healthy samples. In control group, ST1 alone was found in 3.3% of individuals. ST1 was associated with Gingival Index, Clinical Attachment Level (p ≤ 0.03) and with the total bacterial count (p = 0.02). T. tenax alone was associated with P. gingivalis, T. denticola and E. nodatum (p ≤ 0,02). After therapy, only T. tenax detection decreased significantly (p = 0.004) and no association between the protozoan elimination and improvement of pathological sites was found.

Conclusions: Protozoans were associated with some clinical parameters and/or periodontopathogens in patients with periodontitis.

Development of a new TaqMan PCR assay for the detection of both Entamoeba gingivalis genotypes

Entamoeba gingivalis is a parasitic protozoan found in the mouth of patients suffering from periodontitis, a widespread oral disease with an underestimated prevalence and major consequences on health. We present the development of the first TaqMan PCR assay targeting both E. gingivalis subtypes. This method has been evaluated on 50 samples from patients diagnosed with periodontitis in comparison with 2 different conventional PCRs, and a real-time SYBR Green PCR. Fifty percent of the samples were found positive for the E. gingivalis ST1 subtype with this new PCR, the SYBR Green PCR and one of the conventional PCRs. Among the 25 remaining samples, 12 (24%) were found positive for the E. gingivalis ST2 kamaktlii variant. This new TaqMan PCR could be used before and after periodontitis treatment to follow its efficacy and measure the parasite load in order to better understand the role of these parasites in oral diseases.

Specific clones of Trichomonas tenax are associated with periodontitis

Trichomonas tenax, an anaerobic protist difficult to cultivate with an unreliable molecular identification, has been suspected of involvement in periodontitis, a multifactorial inflammatory dental disease affecting the soft tissue and bone of periodontium. A cohort of 106 periodontitis patients classified by stages of severity and 85 healthy adult control patients was constituted. An efficient culture protocol, a new identification tool by real-time qPCR of T. tenax and a Multi-Locus Sequence Typing system (MLST) based on T. tenax NIH4 reference strain were created. Fifty-three strains of Trichomonas sp. were obtained from periodontal samples. 37/106 (34.90%) T. tenax from patients with periodontitis and 16/85 (18.80%°) T. tenax from control patients were detected by culture (p = 0.018). Sixty of the 191 samples were tested positive for T. tenax by qPCR, 24/85 (28%) controls and 36/106 (34%) periodontitis patients (p = 0.089). By combining both results, 45/106 (42.5%) patients were positive by culture and/or PCR, as compared to 24/85 (28.2%) controls (p = 0.042). A link was established between the carriage in patients of Trichomonas tenax and the severity of the disease. Genotyping demonstrates the presence of strain diversity with three major different clusters and a relation between disease strains and the periodontitis severity (p<0.05). More frequently detected in periodontal cases, T. tenax is likely to be related to the onset or/and evolution of periodontal diseases.

Reassessing the Role of Entamoeba gingivalis in Periodontitis

The protozoan Entamoeba gingivalis resides in the oral cavity and is frequently observed in the periodontal pockets of humans and pets. This species of Entamoeba is closely related to the human pathogen Entamoeba histolytica, the agent of amoebiasis. Although E. gingivalis is highly enriched in people with periodontitis (a disease in which inflammation and bone loss correlate with changes in the microbial flora), the potential role of this protozoan in oral infectious diseases is not known. Periodontitis affects half the adult population in the world, eventually leads to edentulism, and has been linked to other pathologies, like diabetes and cardiovascular diseases. As aging is a risk factor for the disorder, it is considered an inevitable physiological process, even though it can be prevented and cured. However, the impact of periodontitis on the patient's health and quality of life, as well as its economic burden, are underestimated. Commonly accepted models explain the progression from health to gingivitis and then periodontitis by a gradual change in the identity and proportion of bacterial microorganisms in the gingival crevices. Though not pathognomonic, inflammation is always present in periodontitis. The recruitment of leukocytes to inflamed gums and their passage to the periodontal pocket lumen are speculated to fuel both tissue destruction and the development of the flora. The individual contribution to the disease of each bacterial species is difficult to establish and the eventual role of protozoa in the fate of this disease has been ignored. Following recent scientific findings, we discuss the relevance of these data and propose that the status of E. gingivalis be reconsidered as a potential pathogen contributing to periodontitis.

Selection of Appropriate Metagenome Taxonomic Classifiers for Ancient Microbiome Research

Ancient biomolecules from oral and gut microbiome samples have been shown to be preserved in the archaeological record. Studying ancient microbiome communities using metagenomic techniques offers a unique opportunity to reconstruct the evolutionary trajectories of microbial communities through time. DNA accumulates specific damage over time, which could potentially affect taxonomic classification and our ability to accurately reconstruct community assemblages. It is therefore necessary to assess whether ancient DNA (aDNA) damage patterns affect metagenomic taxonomic profiling. Here, we assessed biases in community structure, diversity, species detection, and relative abundance estimates by five popular metagenomic taxonomic classification programs using in silico-generated data sets with and without aDNA damage. Damage patterns had minimal impact on the taxonomic profiles produced by each program, while false-positive rates and biases were intrinsic to each program. Therefore, the most appropriate classification program is one that minimizes the biases related to the questions being addressed.

Metagenomics enables the study of complex microbial communities from myriad sources, including the remains of oral and gut microbiota preserved in archaeological dental calculus and paleofeces, respectively. While accurate taxonomic assignment is essential to this process, DNA damage characteristic of ancient samples (e.g., reduction in fragment size and cytosine deamination) may reduce the accuracy of read taxonomic assignment. Using a set of in silico-generated metagenomic data sets, we investigated how the addition of ancient DNA (aDNA) damage patterns influences microbial taxonomic assignment by five widely used profilers: QIIME/UCLUST, MetaPhlAn2, MIDAS, CLARK-S, and MALT. In silico-generated data sets were designed to mimic dental plaque, consisting of 40, 100, and 200 microbial species/strains, both with and without simulated aDNA damage patterns. Following taxonomic assignment, the profiles were evaluated for species presence/absence, relative abundance, alpha diversity, beta diversity, and specific taxonomic assignment biases. Unifrac metrics indicated that both MIDAS and MetaPhlAn2 reconstructed the most accurate community structure. QIIME/UCLUST, CLARK-S, and MALT had the highest number of inaccurate taxonomic assignments; false-positive rates were highest by CLARK-S and QIIME/UCLUST. Filtering out species present at <0.1% abundance greatly increased the accuracy of CLARK-S and MALT. All programs except CLARK-S failed to detect some species from the input file that were in their databases. The addition of ancient DNA damage resulted in minimal differences in species detection and relative abundance between simulated ancient and modern data sets for most programs. Overall, taxonomic profiling biases are program specific rather than damage dependent, and the choice of taxonomic classification program should be tailored to specific research questions.

IMPORTANCE Ancient biomolecules from oral and gut microbiome samples have been shown to be preserved in the archaeological record. Studying ancient microbiome communities using metagenomic techniques offers a unique opportunity to reconstruct the evolutionary trajectories of microbial communities through time. DNA accumulates specific damage over time, which could potentially affect taxonomic classification and our ability to accurately reconstruct community assemblages. It is therefore necessary to assess whether ancient DNA (aDNA) damage patterns affect metagenomic taxonomic profiling. Here, we assessed biases in community structure, diversity, species detection, and relative abundance estimates by five popular metagenomic taxonomic classification programs using in silico-generated data sets with and without aDNA damage. Damage patterns had minimal impact on the taxonomic profiles produced by each program, while false-positive rates and biases were intrinsic to each program. Therefore, the most appropriate classification program is one that minimizes the biases related to the questions being addressed.

Prevalence of two Entamoeba gingivalis ST1 and ST2-kamaktli subtypes in the human oral cavity under various conditions

Advances in molecular biology have facilitated analyses of the oral microbiome; however, the parasites role is poorly understood. Periodontal disease is a multifactorial process involving complex interactions among microorganisms, the host, and environmental factors. At present, the precise composition of the mouth parasites microbiota is unclear. Two protozoan species have been detected in the oral microbiota: Trichomonas tenax and Entamoeba gingivalis, and a new variant, E. gingivalis-ST2-kamaktli, was recently identified by us. In this study, both E. gingivalis and the new E. gingivalis-ST2-kamaktli variant were detected in the oral cavities of people with healthy periodontium, individuals undergoing orthodontic treatment, and patients with periodontal disease. In the group with healthy periodontium, the prevalence of E. gingivalis-ST1 was 48.6% and that of E. gingivalis-ST2-kamaktli 29.5%, with a combined prevalence of 54.3%. In patients undergoing orthodontics treatment, 81.2% carried both amoebas, with 47.5% having E. gingivalis-ST1 and 73.8% E. gingivalis-ST2-kamaktli. In people with periodontal disease, the prevalence of E. gingivalis-ST1 was 57.8%, and that of E. gingivalis-ST2-kamaktli 50.0%, with a combined prevalence of 73.5%; hence, E. gingivalis-ST1 and E gingivalis-ST2-kamaktli were detected in all three groups. The question arises, what are E. gingivalis-ST1 and E. gingivalis-ST2-kamaktli doing in the oral cavity? Although, the answer remains unclear, our results suggest that each amoeba subtype is genetically distinct, and they exhibit different patterns of infectious behavior. We hypothesize that E. gingivalis-ST1 and E. gingivalis-ST2-kamaktli may represent separate species. Our data contribute to better understanding of the roles of E. gingivalis-ST1 and E. gingivalis-ST2-kamaktli in the oral microbiota.

A new subtype of Entamoeba gingivalis: "E. gingivalis ST2, kamaktli variant"

Entamoeba gingivalis is a protozoan that resides in the oral cavity. Using molecular biology techniques, we identified a novel organism that shares the same ecological niche as E. gingivalis. To differentiate this organism from E. gingivalis, we named it “kamaktli variant.” By sequencing the 18S-ITS1-5.8S-ITS2 rRNA region, we demonstrated that kamaktli variant is 89% identical to E. gingivalis. To elucidate the relationship between kamaktli variant and E. gingivalis, we performed a phylogenetic analysis. Both taxa clustered in the same clade with high support, indicating that the amoebas are closely related (98/99/1.00, maximum parsimony/maximum likelihood/MrBayes, respectively). Given this information, we propose that these molecular differences between kamaktli variant and E. gingivalis ST1 are sufficient to distinguish them as independent subtypes, and we name the new subtype “E. gingivalis ST2, kamaktli variant.”

Dysbiosis in chronic periodontitis: Key microbial players and interactions with the human host

Periodontitis is an extremely prevalent disease worldwide and is driven by complex dysbiotic microbiota. Here we analyzed the transcriptional activity of the periodontal pocket microbiota from all domains of life as well as the human host in health and chronic periodontitis. Bacteria showed strong enrichment of 18 KEGG functional modules in chronic periodontitis, including bacterial chemotaxis, flagellar assembly, type III secretion system, type III CRISPR-Cas system, and two component system proteins. Upregulation of these functions was driven by the red-complex pathogens and candidate pathogens, e.g. Filifactor alocis, Prevotella intermedia, Fretibacterium fastidiosum and Selenomonas sputigena. Nine virulence factors were strongly up-regulated, among them the arginine deiminase arcA from Porphyromonas gingivalis and Mycoplasma arginini. Viruses and archaea accounted for about 0.1% and 0.22% of total putative mRNA reads, respectively, and a protozoan, Entamoeba gingivalis, was highly enriched in periodontitis. Fourteen human transcripts were enriched in periodontitis, including a gene for a ferric iron binding protein, indicating competition with the microbiota for iron, and genes associated with cancer, namely nucleolar phosphoprotein B23, ankyrin-repeat domain 30B-like protein and beta-enolase. The data provide evidence on the level of gene expression in vivo for the potentially severe impact of the dysbiotic microbiota on human health.

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 Oral Microbiome in Health and Its Implication in Oral and Systemic Diseases

The oral microbiome can alter the balance between health and disease, locally and systemically. Within the oral cavity, bacteria, archaea, fungi, protozoa, and viruses may all be found, each having a particular role, but strongly interacting with each other and with the host, in sickness or in health. A description on how colonization occurs and how the oral microbiome dynamically evolves throughout the host's life is given. In this chapter the authors also address oral and nonoral conditions in which oral microorganisms may play a role in the etiology and progression, presenting the up-to-date knowledge on oral dysbiosis as well as the known underlying pathophysiologic mechanisms involving oral microorganisms in each condition. In oral pathology, oral microorganisms are associated with several diseases, namely dental caries, periodontal diseases, endodontic infections, and also oral cancer. In systemic diseases, nonoral infections, adverse pregnancy outcomes, cardiovascular diseases, and diabetes are among the most prevalent pathologies linked with oral cavity microorganisms. The knowledge on how colonization occurs, how oral microbiome coevolves with the host, and how oral microorganisms interact with each other may be a key factor to understand diseases etiology and progression.

The Effect of Nonsurgical Periodontal Therapy on Trichomonas Tenax and Entamoeba Gingivalis in Patients with Chronic Periodontitis

STATEMENT OF THE PROBLEM

Trichomonas tenax and Entamoeba gingivalis are commensal protozoa which inhabit the human oral cavity. These parasites are found in patients with poor oral hygiene and might be a reason for progressive periodontal diseases.

PURPOSE

The aim of this study was to evaluate the effect of nonsurgical periodontal treatment on the frequency of these protozoa in saliva and plaque samples.

MATERIALS AND METHOD

In this clinical trial, samples of saliva and dental plaque were collected from 46 patients with moderate to severe chronic periodontitis before and after periodontal therapy. The samples were assessed for the frequency of parasites.

RESULTS

The frequency of Entamoeba gingivalis was reduced in saliva (p= 0.007) and plaque (p= 0.027) three weeks after the treatment. Likewise, the frequency of Trichomonas tenax reduced in saliva (p= 0.030); however, the decrease was not significant in plaque (p= 0.913). Trichomonas tenax frequency in dental plaque directly related to the severity of periodontitis (r= 0.565, p≤ 0.000). In contrast, the number of Entamoeba gingivalis in both saliva (r= -0.405, p≤ 0.005) and plaque (r= -0.304, p= 0.040) was inversely related with the severity of the periodontal disease.

CONCLUSION

Nonsurgical periodontal treatment could reduce the number of Trichomonas Tenax and Entamoeba gingivalis in the oral environment of patients with chronic periodontitis.

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.

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.

Interkingdom networking within the oral microbiome

Different sites within the oropharynx harbour unique microbial communities. Co-evolution of microbes and host has resulted in complex interkingdom circuitries. Metabolic signalling is crucial to these processes, and novel microbial communication factors are progressively being discovered. Resolving interkingdom networks will lead to better understanding of oral health or disease aetiology.