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

Abstract

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.”

Reassessing the Role of Entamoeba gingivalis in Periodontitis

“…Indeed, evidence about the kinetics of periodontitis setup is scarce and other possible agents must be considered. First, the ST2 “kamaktli” variant, with a high genetic divergence from E. gingivalis ST1 (Garcia et al, 2018b ) reminds us that strains of parasites may not be equally virulent or may not have the same tropism (Garcia et al, 2018a ). Second, some transcripts from archaea species and viruses are differently abundant between the healthy and the diseased (Deng et al, 2017 ).…”

“…Recently, transcriptomics revealed that E. gingivalis 18s rRNA sequence was detected in all (4/4) periodontal pockets and was less abundant in 60% (6/10), or undetected in 40% (4/10) of healthy sites (Deng et al, 2017 ). Furthermore, genetic variants of E. gingivalis have been identified (Cembranelli et al, 2013 ; Garcia et al, 2018b ) and different levels of virulence reflected at the transcriptomic levels in genetically identical parasites (Santi-Rocca et al, 2008 ) may account for discrepancies in their molecular detection as compared with microscopy or clinical diagnoses. The new clinical characterization of periodontitis (Tonetti et al, 2018 ) will avoid further confusion about the definition of health and various disease grades, that may also be responsible for variability between the studies.…”

“…The genetic variability in the species E. gingivalis seems important (Garcia et al, 2018b ) and the genetic distance between the ST1 and ST2 variants may indicate great differences in their biology, accounting for their probable association with different pathologies (Garcia et al, 2018a ). As the genotyping of E. gingivalis is based on the only gene that has been sequenced, a greater genetic variability may be expected, and further epidemiological studies will precise if some subtypes colonize specific sulcus/pocket environments and, thus, correlate with different clinical outcomes.…”

Oral colonization by Entamoeba gingivalis and Trichomonas tenax: PCR-based study in health, gingivitis, and periodontitis

“…The copyright holder for this preprint this version posted July 18, 2020. ; https://doi.org/10.1101/2020.07.16.20155861 doi: medRxiv preprint by assessing the prevalence of the other strain in the future studies (42,54,56). For the negative samples we did not rule out inhibition of PCR completely, which can make our results an underestimation of the true prevalence.…”

“…Several studies aimed to investigate parasitic oral colonization among healthy individuals and those with periodontal disease with remarkably variable results (34)(35)(36)(37)(38)(39)(40)(41). Such variability can be related to adoption of different approaches for parasite detection, the existence of previously unknown genetic variants of oral parasites, in addition to limitations of small sample sizes, and possible bias in selection of study subjects among others as reviewed recently (42,43).…”