Cryptic Genetic Diversity in
            <i>Dientamoeba fragilis</i>

Johnson, J. A.; Clark, C Graham

doi:10.1128/jcm.38.12.4653-4654.2000

Cited by 62 publications

(27 citation statements)

References 10 publications

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“…It is possible that multiple species or subspecies exist within the genus Dientamoeba and that only certain subtypes are associated with disease. 109,110 Links between the presence or absence of disease and different subtypes have been described in other enteric protozoa. 96 Therefore, this is a plausible explanation for the asymptomatic carriage of Dientamoeba reported in some patients.…”

Section: Genetic Diversity In Dientamoeba and Links To Diseasementioning

confidence: 99%

“…It is reported that most patients with genotype 1 experience symptoms while a small minority do not. 6,46,91,109 Only a small amount of data exists for genotype 2. The most recent report of genotype 2 was discussed by Johnson and Clark 109 who isolated the organism into culture media from the stool of a patient with diarrhea.…”

Section: Genetic Diversity In Dientamoeba and Links To Diseasementioning

confidence: 99%

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A review ofDientamoeba fragiliscarriage in humans: Several reasons why this organism should be considered in the diagnosis of gastrointestinal illness

Barratt¹,

Harkness²,

Marriott³

et al. 2011

Gut Microbes

126

131

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Dientamoeba fragilis is a protozoan that inhabits the human gut. It is approximately 100 years since Dientamoeba's discovery and first description when it was described as a rare and harmless commensal. Since then it has struggled to gain recognition as a pathogen despite the evidence supporting its pathogenicity. Dientamoeba remains neglected, probably due to the misconceptions that it is uncommon and non-pathogenic. Usually, carriage of Dientamoeba is associated with symptoms such as abdominal pain and diarrhea. Moreover, antimicrobial therapy followed by resolution of symptoms coincides with the eradication of Dientamoeba. This manuscript reviews the scientific literature relating to Dientamoeba's prevalence and pathogenicity. While much of the evidence supporting its pathogenicity is only circumstantial, it is apparent that most researchers agree that Dientamoeba is pathogenic. Therefore, in symptomatic patients who harbor Dientamoeba and no other pathogen, Dientamoeba should be considered as the etiological agent and treated as such.

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Section: Genetic Diversity In Dientamoeba and Links To Diseasementioning

confidence: 99%

Section: Genetic Diversity In Dientamoeba and Links To Diseasementioning

confidence: 99%

A review ofDientamoeba fragiliscarriage in humans: Several reasons why this organism should be considered in the diagnosis of gastrointestinal illness

Barratt¹,

Harkness²,

Marriott³

et al. 2011

Gut Microbes

126

131

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show abstract

“…No cyst stage is identified yet. Originally, D. fragilis was considered an amoeba, but based on ultra structural characteristics it has been established that it is a trichomonad (Johnson and Clark, 2000;Banik et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Detection of Dientamoeba fragilis in patients referred to Chaloos Medical Care Centers by nested – polymerase chain reaction (PCR) method

Ghazanchaei¹,

Shargh²,

Shabani³

et al. 2012

Afr. J. Biotechnol.

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Dientamoeba fragilis is a protozoan that inhabits the human colon and is responsible in degrees for clinical symptoms. These symptoms are: Local stomach pains, loss of weight and appetite and vomiting. Treatment with anti-parasite drugs will improve the symptoms. Due to misdiagnosis, prolonged undesired clinical signs can remain in patient. Diagnosis in stool specimens uses standard Iron-Haematoxylin staining and molecular polymerase chain reaction (PCR) and Nested-PCR methods that differ in sensitivity and specifity. The results presented here confirmed the sensitivity and specificity of 85 and 100% respectively. All negative results with staining method were also negative by PCR but six positive reported results were detected by staining and one positive sample was not detected by molecular method. This maybe the result of delay in processing samples for diagnosis which may mean the DNA is destroyed and made undetectable.

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“…Two genotypes have been identified that differ significantly in the sequence of their small subunit ribosomal RNA (SSU rRNA) gene sequences (Johnson and Clark 2000;Peek, Reedeker, and van Gool 2004;Silberman, Clark, and Sogin 1996;Stark et al 2005a;Windsor, Clark, and Macfarlane 2004). However, more than 99% of isolates belong to 1 genotype.…”

mentioning

confidence: 99%

Internal Transcribed Spacer Dimorphism and Diversity in Dientamoeba fragilis

Windsor¹,

Macfarlane²,

Clark³

2006

J Eukaryotic Microbiology

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The internal transcribed spacer (ITS) region of the ribosomal RNA operon is frequently used for detecting sequence variation among closely related species as it is usually homogeneous within strains but evolves more rapidly than ribosomal RNA coding regions. We have studied this region in both genotypes of the human intestinal parasite Dientamoeba fragilis. In contrast to most organisms, we have identified extensive variation between copies of the sequence within the same strain. The ITS occurs in 2 major forms in each genotype but additional heterogeneity is also present within each form. The significance of this finding is unclear, but the only precedent for such variation is in the Apicomplexa, which have multiple dispersed ribosomal RNA operons in contrast to the tandem arrays found in most other eukaryotes.

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Cryptic Genetic Diversity in Dientamoeba fragilis

Cited by 62 publications

References 10 publications

A review ofDientamoeba fragiliscarriage in humans: Several reasons why this organism should be considered in the diagnosis of gastrointestinal illness

A review ofDientamoeba fragiliscarriage in humans: Several reasons why this organism should be considered in the diagnosis of gastrointestinal illness

Detection of Dientamoeba fragilis in patients referred to Chaloos Medical Care Centers by nested – polymerase chain reaction (PCR) method

Internal Transcribed Spacer Dimorphism and Diversity in Dientamoeba fragilis

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