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Entamoeba histolytica
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
William A. Petri, Jonathan I. Ravdin
Entamoeba gingivalis trophozoites have a cytoplasm full of dark staining bodies and food vacuoles. E. gingivalis is associated with poor dental hygiene and must be distinguished from E. histolytica in the sputum of patients with lung abscess. Entamoeba histolytica trophozoites are large (12-60 μm), exhibit unidirectional motility, and can contain ingested erythrocytes. The cysts of E. histolytica contain up to four nuclei. The E. histolytica-like Laredo strain is nonpathogenic and grows optimally at 24°C in vitro, as opposed to an optimal growth temperature of 35°C for E. histolytica (14). Entamoeba hartmanni, formerly called the small race of E. histolytica, is a nonpathogenic commensal of identical morphology, but its trophozoite or cyst forms are smaller than those of E. histolytica (<12μm) (15). Entamoeba coli is frequently isolated together with E. histolytica in endemic areas in the tropics but is nonpathogenic. The trophozoites of E. coli never contain ingested erythrocytes, and their motility is more sluggish and less directed than that of E. histolytica. Entamoeba coli cysts contain up to eight nuclei (12,13). Entamoeba polecki infects pigs and monkeys in the tropics and has recently been associated with human disease in Upper Volta (16) and in Papua New Guinea. It is identified by its characteristics uninucleate cyst with a large karysome in the nucleus.
Factors Controlling the Microflora of the Healthy Mouth
Published in Michael J. Hill, Philip D. Marsh, Human Microbial Ecology, 2020
In gingivitis, the maximal depth of the gingival pocket is about 3 mm. Marginal periodontitis is a destructive inflammatory disease with breakdown of the collagen fibers and bone supporting the teeth. Periodontal pockets, often 5 to 10 mm deep, are formed between tooth surface and gingiva by proliferation of epithelium in an apical direction (Figures 2 and 17). Subgingival plaque in such pathological pockets harbors relatively few streptococci and actinomyces, while there is a greater predominance of the obligate anaerobes, Gram-negative rods, and treponemes already mentioned as members of supra- and subgingival plaque in gingivitis (Figures 15 and 23). The protozoa, Entamoeba gingivalis and Trichomonas tenax are also regularly present.48 Some of the species constituting increased percentages of the microflora in advancing, destructive disease have received much attention as possible etiological agents (notably B. gingivalis, B. intermedius, F. nucleatum, A. actinomycetemcomitans, W. recta, and Treponema spp.).12 Actually, a large number of species appear correlated with disease, and different ones are increased in different pockets.8,56
The Role of Dentistry in Cardiovascular Health and General Well-Being
Published in Stephen T. Sinatra, Mark C. Houston, Nutritional and Integrative Strategies in Cardiovascular Medicine, 2015
Patients are often unaware that they have periodontal disease. Therefore, to detect a problem at the earliest stage, it is very important to maintain regular dental visits. As part of an initial examination, I do a periodontal probing around every tooth. If I find a pocket of more than 3 mm deep, I suspect that bone has been lost; however, this is just historical information. How do I know if the pocket is actively infected and if the infectious process is ongoing? Bleeding on probing is one indication that this may be occurring. However, I find that the best way to make this determination is by viewing a plaque sample. Plaque is the sticky substance that you feel on your teeth at the end of the day. A sample can be gathered or taken from under the gum as well as from a pocket. This sample is then placed on a glass slide in a solution similar to saliva, and a coverslip is placed over it. Using a phase-contrast microscope, I can view the sample at a magnification of 400×. A healthy slide will have certain types of bacteria, but not a lot of “activity,” whereas an unhealthy slide will be characterized by a lot of activity, lots of white blood cells, spirochetes, and, usually, amoebas. An amoeba is a parasite, and a spirochete is a snake-like bacteria. The spirochete associated with periodontal disease is called Treponema denticola. The specific amoeba associated with periodontal disease is called Entamoeba gingivalis. T. denticola and E. gingivalis are not seen in a healthy mouth. An unhealthy slide sample taken from a pocket would indicate an ongoing infection in that pocket. A healthy slide sample taken from a pocket would indicate that there had previously been a problem, but that it was presently quiescent. No pockets, but a microladen slide, tells me that a person may be at risk, at some point in the future, for periodontal disease and possibly other problems. As you can see, the use of a phase-contrast microscope in the dental office is very important.
Protozoans in subgingival biofilm: clinical and bacterial associated factors and impact of scaling and root planing treatment
Published in Journal of Oral Microbiology, 2020
Marie Dubar, Marie-Laure Zaffino, Thomas Remen, Nathalie Thilly, Lisiane Cunat, Marie-Claire Machouart, Catherine Bisson
The analysis of the periodontal biofilm revealed the presence of many different microorganisms including protozoans. A number of studies have evaluated the presence of protozoans in patients with periodontal diseases and the frequency of detection of Entamoeba gingivalis and Trichomonas tenax varied respectively from 12% to 69% and from 6% to 38.5% according to the authors [2–4]. After the discovery of genetic variation of E. gingivalis in immunocompromised patients by [5], a new subtype of E. gingivalis isolated from samples of patient with periodontitis has been recently identified and named kamaktli variant. The periodontal parameters associated with the presence of this subtype have not been described [5,6]. The differences in collection and identification protocols (microscopic observation/molecular tools), in the study population (adult/children, patients with or without systemic disease) and the inadequate characterization of periodontal diseases make it difficult to draw solid conclusions on the real prevalence of these microorganisms in periodontal disease. Moreover, no studies, except that of Linke’s [7], have detailed the periodontal pocket depth associated with the presence of these protozoans.
Relationship between human immunodeficiency virus (HIV-1) infection and chronic periodontitis
Published in Expert Review of Clinical Immunology, 2018
Tábata Larissa S. Pólvora, Átila Vinícius V. Nobre, Camila Tirapelli, Mário Taba, Leandro Dorigan de Macedo, Rodrigo Carvalho Santana, Bruno Pozzetto, Alan Grupioni Lourenço, Ana Carolina F. Motta
Studies in the post-ART era have reported the presence of microorganisms not commonly found in the subgingival environment, including gram-positive commensal bacteria of the gastrointestinal tract as Clostridium difficile and Enterococcus faecalis, oral commensal microorganisms as Candida albicans, Mycoplasma salivarium, Entamoeba gingivalis, and opportunistic bacteria that frequently affect the respiratory or urinary tract as Staphylococcus epidermidis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii [10,44,46]. Species of the Neisseria genus were detected in dental biofilm and saliva samples of HIV-1-infected individuals but no association with inflammation, immune parameters, or functional gene content was identified [47]. Moreover, Streptococcus mitis, which has the potential to transfer virulence factors to other bacteria, and Capnocytophaga sp., a known opportunistic commensal pathogen involved in the pathogenesis of periodontal diseases, were also detected in saliva samples [48,49]. Veillonella parvula, Prevotella pallens, Campylobacter rectus, Campylobacter concisus, and Megasphaera micronuciform were found in tongue microbiota, which may be associated with caries, periodontal diseases, and systemic infections in HIV-1-infected subjects [50].
Entamoeba gingivalis: epidemiology, genetic diversity and association with oral microbiota signatures in North Eastern Tanzania
Published in Journal of Oral Microbiology, 2021
Christen Rune Stensvold, Michelle Nielsen, Vito Baraka, Rolf Lood, Kurt Fuursted, Henrik Vedel Nielsen
The genus Entamoeba comprises several species known to colonise the human gastrointestinal tract [1,2]. Most of these produce cysts; however, for Entamoeba gingivalis, a cyst stage remains to be confirmed. This species is found mainly in the oral cavity, but has also been found in samples from genital tracts of intrauterine contraceptive device users [3]. Transmission occurs via contaminated food or mouth utensils, mouth droplets and kissing [4,5]. E. gingivalis may be a direct or indirect cause of periodontal disease [4,6–8], a condition affecting about 538 million people in 2015 [9], and which is a frequent cause of edentulism.