Clinical Characteristics and Endoscopic Findings Associated With Blastocystis Hominis in Healthy Adults

Chen, Te‐Li; Chan, Che‐Chang; Chen, Hsin-Pai; Fung, Chang-Phoné; Lin, Chih-Pei; Chan, Wan Leong; Liu, Cheng-Yi

doi:10.4269/ajtmh.2003.69.213

Cited by 56 publications

(40 citation statements)

References 27 publications

(45 reference statements)

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“…This is in contrast to reports that suggested otherwise (43,131,180,274). Certain populations may be susceptible to Blastocystis-associated disorders, and risk factors (176,196) and children with nephrotic syndrome receiving corticosteroids (173).…”

Section: Epidemiology and Prevalencecontrasting

confidence: 56%

“…There are no reports of Blastocystis-associated dysentery, and it appears that the parasite is generally noninvasive, as indicated by endoscopy (43,76,329,330) and histology of experimentally infected animals (5,152,187). An interesting case study described Blastocystis trophozoites present in the liver abscess aspirate of a 63-year-old man with a 5-day history of fever and blood-tinged watery diarrhea (102).…”

Section: Infection and Diseasementioning

confidence: 99%

“…Among the studies that purported a lack of association between Blastocystis infection and intestinal disease, many of them focused on the distribution of the parasite between symptomatic and asymptomatic individuals (11,43,81,94,131,216,247,275). Such studies indicated either no significant difference between the prevalences of the parasite in either group (11,94,131,216,275) or a higher prevalence in asymptomatic individuals (43,81,247). Leder et al (131) conducted a case-controlled study in a cohort of 2,800 people and concluded that there was no correlation between clinical symptoms and Blastocystis infection in immunocompetent individuals.…”

Section: Infection and Diseasementioning

confidence: 99%

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New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

Tan¹

2008

Clin Microbiol Rev

609

715

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SUMMARY Blastocystis is an unusual enteric protozoan parasite of humans and many animals. It has a worldwide distribution and is often the most commonly isolated organism in parasitological surveys. The parasite has been described since the early 1900s, but only in the last decade or so have there been significant advances in our understanding of Blastocystis biology. However, the pleomorphic nature of the parasite and the lack of standardization in techniques have led to confusion and, in some cases, misinterpretation of data. This has hindered laboratory diagnosis and efforts to understand its mode of reproduction, life cycle, prevalence, and pathogenesis. Accumulating epidemiological, in vivo, and in vitro data strongly suggest that Blastocystis is a pathogen. Many genotypes exist in nature, and recent observations indicate that humans are, in reality, hosts to numerous zoonotic genotypes. Such genetic diversity has led to a suggestion that previously conflicting observations on the pathogenesis of Blastocystis are due to pathogenic and nonpathogenic genotypes. Recent epidemiological, animal infection, and in vitro host-Blastocystis interaction studies suggest that this may indeed be the case. This review focuses on such recent advances and also provides updates on laboratory and clinical aspects of Blastocystis spp.

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Section: Epidemiology and Prevalencecontrasting

confidence: 56%

Section: Infection and Diseasementioning

confidence: 99%

Section: Infection and Diseasementioning

confidence: 99%

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New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

Tan¹

2008

Clin Microbiol Rev

609

715

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“…is not associated with pathogenicity. [12][13] There are different subtypes of Blastocystis spp. based on genotyping data.…”

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confidence: 99%

Polymerase Chain Reaction Based Subtyping of Blastocystis spp. Isolates from Symptomatic Patients in Turkey

Sakalar¹,

Kandemir²,

Uyar³

et al. 2013

Turkiye Klinikleri J Med Sci

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A AB BS ST TR RA AC CT T O Ob bj je ec ct ti iv ve e: : Blastocystis spp. is a common parasite found in human intestinal tract; however its pathogenic role and factors involved is still under investigation. There are 13 different subtypes of Blastocystis spp. based on genotype analysis. In this study, subtypes of Blastocystis spp. were analyzed in 29 symptomatic patients who were positive for Blastocystis spp. in Erciyes University Hospital. M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : Stool samples from patients were confirmed to be positive for Blastocystis spp. by light microscopy. Genomic DNA was isolated from stool samples of the patients, and Blastocystis spp. isolates were classified into subtypes using polymerase chain reaction using 7 subtype-specific primers. Subtypes, symptoms and the presence of additional parasites were comparatively analyzed for each patient. R Re es su ul lt ts s: : Among symptomatic patients, subtypes 3, 1, 2 and 4 were found in 55.2, 37.9, 13.8 and 6.8% of the patients, respectively. There were mixed infections of different subtypes such as 1 and 2 in one patient, 1 and 3 in another patient, and 3 and 4 in two patients. Most commonly encountered symptoms were abdominal pain and diarrhea followed by dermatitis. Additional parasites such as one of the flagellate or amoeba species were observed in 45.5% (5 out of 11 patients), 25% (1 out of 4 patients), 25% (4 out of 16 patients) and 50% (1 out of 2 patients) of patients having subtypes 1, 2, 3 and 4, respectively. C Co on nc cl lu us si io on n: : Our results demonstrate the relative abundance of each Blastocystis spp. subtype in symptomatic patients in Kayseri and surrounding cities. Observed subtypes are aligned as 3, 1, 2 and 4 according to frequency of occurrence.K Ke ey y W Wo or rd ds s: : Blastocystis; polymerase chain reaction; genotype; signs and symptoms; Turkey Ö ÖZ ZE ET T A Am ma aç ç: : Blastocystis spp. insan bağırsak sisteminde bulunan yaygın bir parazittir, bununla birlikte hastalıktaki rolü ve buna yol açan etmenler araştırılmaktadır. Blastocystis spp. genotip analizleri sonucunda 13 alt tipe ayrılmıştır. Bu çalışmada, Erciyes Üniversitesi Hastanesi'nde bulunan ve Blastocystis spp. taşıdığı belirlenen 29 semptomatik hastanın Blastocystis spp. izolatlarının alt tipleri belirlenmiştir. G Ge er re eç ç v ve e Y Yö ön nt te em ml le er r: : Hastalardan alınan dışkı örnekleri ışık mikroskobuyla incelenerek Blastocystis spp. varlığı tespit edilmiştir. Dışkı örneklerinden DNA izolasyonu yapılmış ve polimeraz zincir rekasiyonu yöntemiyle 7 farklı alt tip spesifik primer kullanılarak herbir dışkıdaki Blastocystis spp. parazitleri tiplendirilmiştir. Herbir hasta için alt tip, semptom ve tespit edilen diğer parazitler analiz edilmiştir. B Bu ul lg gu ul la ar r: : Semptomu olan hasta grubunda Blastocystis spp. alt tip 3, 1, 2 ve 4 sırasıyla hastaların %55,2, %37,9, %13,8 ve %6,8'inde tespit edilmiştir. Ayrıca bir hastada 1. ve 2., bir hastada 1. ve 3., ve iki hastada ise 3. ve 4. alt tipler aynı anda tespit e...

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“…Most large studies of symptomatic Blastocystis patients describe a non-inflammatory watery diarrhea with no mucosal ulceration or invasion (Zuckerman et al 1994;Jelinek et al 1997). This study is the first to examine the small bowel in Blastocystis infection, as previous studies have not reported inspecting the terminal ileum at lower endoscopy (Kain et al 1987;Zuckerman et al 1994;Chen et al 2003). Prominent lymphoid tissue in the terminal ileum was the only mucosal abnormality seen in a minority of patients.…”

Section: Clinical Follow Up At 6 Weeksmentioning

confidence: 86%

Are Blastocystis species clinically relevant to humans?

Nagel¹

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ii Seventeen different subtypes of Blastocystis based on the 18S subunit of ribosomal DNA have been described. Using subtyping techniques, the human and animal household contacts of 11 symptomatic Blastocystis-positive patients were studied. All household contacts were found to be positive for Blastocystis spp. The specific subtypes within households had high similarity with the symptomatic patients (94% in human and 88% in animal contacts). Although 18S rDNA subtyping was not sufficient to discriminate genetically identical organisms, the ST findings suggest that intra-household transmission of Blastocystis is almost universal.IBS is a common, heterogeneous condition with no objective biomarker. We studied eradication rates of Blastocystis following administration of different antimicrobial drug regimes. Currently recommended first line therapy for eradication, metronidazole 400 mg three times daily or sulfamethozazole/trimethoprim 160/80mg were administered to 11 symptomatic patients for 14 days. No patient was negative for Blastocystis carriage after therapy with either drug. In a later study 10 diarrhoea-predominant IBS Blastocystispositive patients were given 14 days of triple antimicrobial therapy, namely diloxanide furoate 500mg and secnidazole 400 mg three times daily, and trimethoprimiv sulfamethoxazole 160/80 mg twice daily, with 60% of the patients eradicating the organism. Characteristic changes in the FM profile of IBS patients at a phylum and genus level were observed. However, when the subgroups were analysed there were significant changes seen at different taxonomic levels between the Blastocystis positive and negative IBS groups. The lower serum IgA level present in Blastocystis carriers was hypothesised to result in changes in the FM that enable Blastocystis to flourish with increased epithelial cell contact. Other previously described host factors, such as cytokine polymorphisms in IBS patients that increase IL-8 production and decrease IL-10, may select subjects for immune activation and symptom development. It is not certain if particularIn summary, Blastocystis spp. remain enigmatic organisms that are difficult to clear from our gastrointestinal tracts. Subtyping has increased our epidemiological understanding and infection within households is almost universal. Host immune v responses and FM are significantly different in Blastocystis-positive IBS patients suggesting that this organism may contribute to IBS in some subjects.vi

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Clinical Characteristics and Endoscopic Findings Associated With Blastocystis Hominis in Healthy Adults

Cited by 56 publications

References 27 publications

New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

New Insights on Classification, Identification, and Clinical Relevance of Blastocystis spp

Polymerase Chain Reaction Based Subtyping of Blastocystis spp. Isolates from Symptomatic Patients in Turkey

Are Blastocystis species clinically relevant to humans?

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