Intragenomic Variation in the Internal Transcribed Spacer 1 Region of
            <i>Dientamoeba fragilis</i>
            as a Molecular Epidemiological Marker

Bart, Aldert; Heijden, Harold M. van der; Greve, Sophie; Speijer, Dave; Landman, W. J. M.; Gool, Tom van

doi:10.1128/jcm.00680-08

Cited by 36 publications

(30 citation statements)

References 19 publications

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“…The investigation of genetic variation in D. fragilis SSU rRNA with respect to geographic area has shown that SSU rRNA gene variation is not sufficient to be used as an epidemiological marker [4,47,48]. The SSU rRNA gene sequencing analysis of three D. fragilis isolates were similar and revealed 98% identity between our isolates and two corresponding published reference sequences for D. fragilis (accession nos.…”

Section: Discussionmentioning

confidence: 73%

“…This disparity is not surprising, as manifestations ranging from subclinical to severe gastrointestinal symptoms is typically observed in parasitic enteropathogen infections. This phenomenon is suggested to be related to genetic diversity in D. fragilis, resulting in a heterogeneous species [2,4,8,47,48].…”

Section: Discussionmentioning

confidence: 99%

“…This microorganism shows extensive genetic diversity, comprising variants morphologically related but distinct in their pathogenicity [3][4][5]. Although described about century ago, D. fragilis biology, virulence, pathogenicity, epidemiology, and mode of transmission are not well understood, and findings can be conflicting [4,6,7].…”

Section: Introductionmentioning

confidence: 99%

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Dientamoeba fragilis diagnosis by fecal screening: relative effectiveness of traditional techniques and molecular methods

Hamidi

Meamar

Akhlaghi

et al. 2018

J Infect Dev Ctries

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Introduction: Dientamoeba fragilis, an intestinal trichomonad, occurs in humans with and without gastrointestinal symptoms. Its presence was investigated in individuals referred to Milad Hospital, Tehran. Methodology: In a cross-sectional study, three time-separated fecal samples were collected from 200 participants from March through June 2011. Specimens were examined using traditional techniques for detecting D. fragilis and other gastrointestinal parasites: direct smear, culture, formalin-ether concentration, and iron-hematoxylin staining. The presence of D. fragilis was determined using PCR assays targeting 5.8S rRNA or small subunit ribosomal RNA. Results: Dientamoeba fragilis, Blastocystis sp., Giardia lamblia, Entamoeba coli, and Iodamoeba butschlii were detected by one or more traditional and molecular methods, with an overall prevalence of 56.5%. Dientamoeba was not detected by direct smear or formalin-ether concentration but was identified in 1% and 5% of cases by culture and iron-hematoxylin staining, respectively. PCR amplification of SSU rRNA and 5.8S rRNA genes diagnosed D. fragilis in 6% and 13.5%, respectively. Prevalence of D. fragilis was unrelated to participant gender, age, or gastrointestinal symptoms. Conclusions: This is the first report of molecular assays to screen for D. fragilis in Iran. The frequent finding of D. fragilis via fecal analysis indicated the need to include this parasite in routine stool examination in diagnostic laboratories. As the length of amplification target correlates to the sensitivity of PCR, this assay targeting the D. fragilis 5.8S rRNA gene seems optimal for parasite detection and is recommended in combination with conventional microscopy for diagnosing intestinal parasites.

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

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Dientamoeba fragilis diagnosis by fecal screening: relative effectiveness of traditional techniques and molecular methods

Hamidi

Meamar

Akhlaghi

et al. 2018

J Infect Dev Ctries

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“…Windsor et al (34) identified the multicopy internal transcribed spacer (ITS) genes as a source of genetic diversity within individual D. fragilis isolates, which is unusual among protozoa. This observation eventually led to the development of a C-profiling technique, which could be used to distinguish between isolates (35,36). In another report, Hussein et al (37) detected diversity in the 18S RNA genes of isolates derived from patients with irritable bowel syndrome (IBS) by using PCR with high-resolution melt curve analysis.…”

Section: Genetic Diversitymentioning

confidence: 99%

Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

et al. 2016

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SUMMARYDientamoeba fragilisis a protozoan parasite of the human bowel, commonly reported throughout the world in association with gastrointestinal symptoms. Despite its initial discovery over 100 years ago, arguably, we know less about this peculiar organism than any other pathogenic or potentially pathogenic protozoan that infects humans. The details of its life cycle and mode of transmission are not completely known, and its potential as a human pathogen is debated within the scientific community. Recently, several major advances have been made with respect to this organism's life cycle and molecular biology. While many questions remain unanswered, these and other recent advances have given rise to some intriguing new leads, which will pave the way for future research. This review encompasses a large body of knowledge generated on various aspects ofD. fragilisover the last century, together with an update on the most recent developments. This includes an update on the latest diagnostic techniques and treatments, the clinical aspects of dientamoebiasis, the development of an animal model, the description of aD. fragiliscyst stage, and the sequencing of the firstD. fragilistranscriptome.

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“…The previous study used the D. fragilis strain ATCC 30948 (genotype 2), which has not been found to be associated with gastrointestinal diseases to date and is rarely encountered in human samples (11,25,28). While the majority of studies have shown genotype 1 in nearly all cases (6,31,33,36), testing of this genotype may be more appropriate in terms of clinical significance and may be a possible reason for the different MLC values between the two studies. The true complexity of the bacterial flora contained within these clinical isolates of D. fragilis is summarized in Table 1.…”

Section: To 7)mentioning

confidence: 99%

In Vitro Susceptibility Testing of Dientamoeba fragilis

Nagata

Marriott

Harkness

et al. 2012

Antimicrob Agents Chemother

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Dientamoeba fragilis is a commonly encountered trichomonad which has been implicated as a cause of gastrointestinal disease in humans. Despite the frequency of reports recording infections with this parasite, little research has been undertaken in terms of antimicrobial susceptibility. The aim of this study was to evaluate the susceptibility of D. fragilis to several commonly used antiparasitic agents: diloxanide furoate, furazolidone, iodoquinol, metronidazole, nitazoxanide, ornidazole, paromomycin, secnidazole, ronidazole, tetracycline, and tinidazole. Antibiotic susceptibility testing was performed on four clinical strains of D. fragilis, designated A, E, M, and V, respectively. Molecular testing followed, and all strains were determined to be genotype 1. The activities of antiprotozoal compounds at concentrations ranging from 2 g/ml to 500 g/ml were determined via cell counts of D. fragilis trophozoites grown in dixenic culture. Minimum lethal concentrations (MLCs) were as follows: ornidazole, 8 to 16 g/ml; ronidazole, 8 to 16 g/ml; tinidazole, 31 g/ml; metronidazole, 31 g/ml; secnidazole, 31 to 63 g/ml; nitazoxanide, 63 g/ml; tetracycline, 250 g/ml; furazolidone, 250 to 500 g/ml; iodoquinol, 500 g/ml; paromomycin, 500 g/ml; and diloxanide furoate, >500 g/ml. This is the first study to report the profiles of susceptibility to a wide range of commonly used treatments for clinical isolates of D. fragilis. Our study indicated 5-nitroimidazole derivatives to be the most active compounds in vitro against D. fragilis. Initially described by Jepps and Dobell (18), Dientamoeba fragilis is a protozoan parasite implicated as a cause of gastrointestinal diseases in both developed and developing regions of the world. Infection rates typically range from 0.5% to 16%, with higher rates seen in outbreaks or where personal hygiene is suboptimal (3,17,21,26). The protozoan is recognized to cause chronic infections. In a prospective study, 6,750 patients were screened for D. fragilis, and 32% of patients presented with chronic symptoms (31), including abdominal pain, diarrhea, and nausea. Some authors have linked D. fragilis to irritable bowel syndrome (IBS)-like symptoms (4, 32).Currently, a majority of evidence supports the pathogenic potential of D. fragilis (5). As such, it suggests the need for not only the correct diagnosis but also appropriate treatment (29,30). The parasite responds to a number of antimicrobial compounds, with studies reporting the complete resolution and elimination of parasites following therapy with iodoquinol (8) metronidazole (24), paromomycin (13), and secnidazole (16). In an Australian study, complete resolution and eradication of the organism were observed for most patients following treatments with iodoquinol, paromomycin, or combination therapy, while treatment relapses/ failures were recorded only with the use of metronidazole (29). It is of note that there are no current treatment guidelines for D. fragilis infections in place.While D. fragilis can be readily cultured from clinical samples...

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Intragenomic Variation in the Internal Transcribed Spacer 1 Region of Dientamoeba fragilis as a Molecular Epidemiological Marker

Cited by 36 publications

References 19 publications

Dientamoeba fragilis diagnosis by fecal screening: relative effectiveness of traditional techniques and molecular methods

Dientamoeba fragilis diagnosis by fecal screening: relative effectiveness of traditional techniques and molecular methods

Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

In Vitro Susceptibility Testing of Dientamoeba fragilis

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