Symptomatic infection with<i>Blastocystis</i>sp. subtype 8 successfully treated with trimethoprim–sulfamethoxazole

Stensvold, Christen Rune; Arendrup, Maiken Cavling; Nielsen, Henrik Vedel; Bada, A.M.; Thorsen, Sixtus

doi:10.1179/136485908x278847

Cited by 40 publications

(33 citation statements)

References 12 publications

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“…By phylogenetic analysis, subtypes 8 and 9 cluster most closely to subtypes 4 and 6, respectively (169,214). We have very little information on both these subtypes except that subtype 8 has been reported in three studies (1,214,228), from monkeys, a pheasant, and humans, while subtype 9 was observed in 2 human isolates out of 102 isolates in an epidemiological study (304). These distributions of specific genotypes among various animal hosts should be viewed as tentative and would, in due course, become more representative as additional studies are performed.…”

Section: Phylogenetic Studies and Identification Of Isolates To The Smentioning

confidence: 99%

“…subtype 8 was isolated from a Danish woman suffering from diarrhea, abdominal pain, bloating, and flatulence. No other infectious cause was evident, and her symptoms subsided after a course of trimethoprim-sulfamethoxazole (TMP-SMX) therapy (228). A recent study among Blastocystis isolates from a Turkish hospital revealed the presence of subtypes 1, 2, and 3 among adult and pediatric patients (62).…”

Section: Epidemiology and Prevalencementioning

confidence: 99%

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

Tan¹

2008

Clin Microbiol Rev

612

745

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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: Phylogenetic Studies and Identification Of Isolates To The Smentioning

confidence: 99%

Section: Epidemiology and Prevalencementioning

confidence: 99%

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

Tan¹

2008

Clin Microbiol Rev

612

745

View full text Add to dashboard Cite

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“…However, there were accumulating reports of treatment failure, particularly in patients with severe Blastocystis sp. infections [Haresh et al 1999;Moghaddam et al 2005;Stensvold et al 2008Stensvold et al , 2010, suggesting the existence of extensive variations in drug susceptibility [Mirza et al 2011]. Accordingly, some genes coding for multidrug resistance pump proteins (ATP-binding cassette transporters) were identified in the Blastocystis sp.…”

Section: Treatment Of Blastocystosismentioning

confidence: 99%

“…ST7 genome (Figure 3) [Denoeud et al 2011]. Several standard antimicrobials (cotrimoxazole, ornidazole, nitazoxanide, paromomycin, chloroquine, trimethoprimsulfamethoxazole, iodoquinol, tinidazole, emetine, pentamidine, iodochlorhydroxyquin and furazolidone) may be considered as second-choice drugs [Ok et al 1999;Cimerman et al 2003;Diaz et al 2003;Rossignol et al 2005;Stensvold et al 2008;Mirza et al 2011;Coyle et al 2012]. Even if some of these drugs were shown to be globally effective against Blastocystis sp., treatment failures were also largely reported [Haresh et al 1999;Nigro et al 2003;Mirza et al 2011].…”

Section: Treatment Of Blastocystosismentioning

confidence: 99%

Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis

Wawrzyniak

Poirier

Viscogliosi

et al. 2013

Therapeutic Advances in Infection

171

156

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Blastocystis sp. is among the few enteric parasites with a prevalence that often exceeds 5% in the general population of industrialized countries and can reach 3060% in developing countries. This parasite is frequently found in people who are immunocompromised (patients with human immunodeficiency virus/acquired immunodeficiency syndrome or cancer) and a higher risk of Blastocystis sp. infection has been found in people with close animal contact. Such prevalence in the human population and the zoonotic potential naturally raise questions about the impact of these parasites on public health and has increased interest in this area. Recent in vitro and in vivo studies have shed new light on the pathogenic power of this parasite, suggesting that Blastocystis sp. infection is associated with a variety of gastrointestinal disorders, may play a significant role in irritable bowel syndrome, and may be linked with cutaneous lesions (urticaria). Despite recent significant advances in the knowledge of the extensive genetic diversity of this species, the identification of extracellular proteases as virulence factors and the publication of one isolate genome, many aspects of the biology of Blastocystis sp. remain poorly investigated. In this review, we investigate several biological aspects of Blastocystis sp. (diversity and epidemiology, diagnosis tools and pathophysiology). These data pave the way for the following challenges concerning Blastocystis sp. research: deciphering key biological mechanisms and pathways of this parasite and clarification of its clinical impact in humans.

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“…ST3 is the predominant subtype found in most human studies (6)(7)(8). There have been numerous studies that have highlighted the clinical relevance of Blastocystis, and an association between subtype and symptoms has been made (9)(10)(11)(12). Although the pathogenic potential of this parasite has long been documented, there is still debate on whether Blastocystis infections should be treated and, therefore, only a small number of studies have looked at treatment options for Blastocystis infection (13).…”

mentioning

confidence: 99%

In Vitro Antimicrobial Susceptibility Patterns of Blastocystis

Roberts

Bush

Ellis

et al. 2015

Antimicrob Agents Chemother

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cBlastocystis is the most common human enteric protist with controversial clinical significance. Metronidazole is considered a first-line treatment for Blastocystis infection; however, there has been increasing evidence for the lack of efficacy of this treatment. Treatment failure has been reported in several clinical cases, and recent in vitro studies have suggested the occurrence of metronidazole-resistant strains. In this study, we tested 12 Blastocystis isolates from 4 common Blastocystis subtypes (ST1, ST3, ST4, and ST8) against 12 commonly used antimicrobials (metronidazole, paromomycin, ornidazole, albendazole, ivermectin, trimethoprim-sulfamethoxazole [TMP-SMX], furazolidone, nitazoxanide, secnidazole, fluconazole, nystatin, and itraconazole) at 10 different concentrations in vitro. It was found that each subtype showed little sensitivity to the commonly used metronidazole, paromomycin, and triple therapy (furazolidone, nitazoxanide, and secnidazole). This study highlights the efficacy of other potential drug treatments, including trimethoprim-sulfamethoxazole and ivermectin, and suggests that current treatment regimens be revised. Blastocystis is the most common enteric protist found in humans, with rates of infection ranging from 2% to 100% in developed and developing countries (1, 2). There have been 17 subtypes (STs) identified from humans and animals, with ST1 to ST9 identified in humans (3-5). ST3 is the predominant subtype found in most human studies (6-8). There have been numerous studies that have highlighted the clinical relevance of Blastocystis, and an association between subtype and symptoms has been made (9-12). Although the pathogenic potential of this parasite has long been documented, there is still debate on whether Blastocystis infections should be treated and, therefore, only a small number of studies have looked at treatment options for Blastocystis infection (13). Most case studies report first-line treatment with metronidazole and found various rates of efficacy with ranges of 0% to 100% (10, 14-16). Other antimicrobials that were used to treat Blastocystis infection included iodoquinol, ketoconazole, nitazoxanide, paromomycin, tinidazole, and trimethoprim-sulfamethoxazole (TMP-SMX), all with varied results (17-21). There have only been four previous studies to look at in vitro susceptibility patterns of Blastocystis, all of which have had a small number of study isolates. From these studies though, it is apparent that different subtypes show different susceptibility patterns and that metronidazole is not the most effective treatment for Blastocystis infection (22)(23)(24)(25). In this study, the in vitro susceptibility patterns of 12 different commonly used antiparasitics and antimicrobials (metronidazole, paromomycin, ornidazole, albendazole, ivermectin, trimethoprim-sulfamethoxazole, furazolidone, nitazoxanide, secnidazole, fluconazole, nystatin, and itraconazole) were examined against 12 clinical isolates of Blastocystis from four different subtypes (ST1, ST3, ST4, and ST8) run...

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Symptomatic infection withBlastocystissp. subtype 8 successfully treated with trimethoprim–sulfamethoxazole

Cited by 40 publications

References 12 publications

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

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

Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis

In Vitro Antimicrobial Susceptibility Patterns of Blastocystis

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