Predominance of Blastocystis sp. subtype 4 in rural communities, Nepal

Lee, Ii Li; Tan, Tiong Kai; Tan, P. C.; Nanthiney, D. R.; Biraj, M. K.; Surendra, K. M.; Suresh, Kumar

doi:10.1007/s00436-011-2665-0

Cited by 56 publications

(54 citation statements)

References 40 publications

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“…Even though most individuals appear to host only a single Blastocystis ST, many individuals host multiple Blastocystis STs, indicating that the prevalence of Blastocystis mixed-ST infections is much greater than previously thought. Based on the data generated in our initial analysis (where we failed to detect any mixed infections) and our comparative analysis of data obtained with existing ST-specific primers (especially the STS primers that have been widely used [28,29]) presented here, it is highly likely that the incidence of mixed-ST infections has been greatly underreported to date, owing to methodological limitations. The application of this ST-specific nested PCR assay to other cohorts of human samples, including those from specific disease groups, will enable further-and more detailed-studies of the biological significance of mixed infections.…”

Section: Figmentioning

confidence: 95%

Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population

Scanlan

Stensvold

Cotter

2015

Appl Environ Microbiol

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The human gut is host to a diversity of microorganisms, including the single-celled microbial eukaryote Blastocystis. Research has shown that most carriers host a single Blastocystis subtype (ST), which is unusual given the considerable within-host species diversity observed for other microbial genera in this ecosystem. However, our limited knowledge of both the incidence and biological significance of Blastocystis diversity within hosts (i.e., so-called mixed infections) is likely due to problems with existing methodologies. Here, we developed and applied Blastocystis ST-specific PCRs for the investigation of the most common subtypes of Blastocystis (ST1 to ST4) to a healthy human cohort (n ‫؍‬ 50). We detected mixed infections in 22% of the cases, all of which had been identified as single-ST infections in a previous study using state-of-the-art methods. Our results show that certain STs occur predominantly as either single (ST3 and 4) or mixed (ST1) infections, which may reflect inter alia transient colonization patterns and/or cooperative or competitive interactions between different STs. Comparative analyses with other primers that have been used extensively for ST-specific analysis found them unsuitable for detection of mixed-and, in some cases, single-ST infections. Collectively, our data shed new light on the diversity of Blastocystis within and between human hosts. Moreover, the development of these PCR assays will facilitate future work on the molecular epidemiology and significance of mixed infections in groups of interest, including health and disease cohorts, and also help identify sources of Blastocystis transmission to humans, including identifying potential animal and environmental reservoirs.T he human gut is a complex, open-ended ecosystem that is host to a diversity of microorganisms, including the single-celled microbial eukaryote Blastocystis (1, 2). Blastocystis is a member of the Stramenopiles or Heterokonta branch of the Eukarya (3) and is phylogenetically distinct from other microbial species of Eukarya such as protozoa, molds, and yeasts that also colonize and/or infect the human gut. Blastocystis has a global distribution and is estimated to colonize between 1 billion and 2 billion people worldwide. In addition to humans, Blastocystis spp. are common inhabitants of the gastrointestinal tract (GIT) of a wide range of other mammalian and nonmammalian hosts, such as livestock, primates, reptiles, and insects (4-6). To date, 17 subtypes (STs) have been described, 9 of which have been detected in human populations. The majority of human-associated STs (ϳ90%), however, are categorized into one of four STs (ST1, ST2, ST3, and ST4) (4).One of the most important recent advances in Blastocystis research is the development and application of sensitive PCR methodologies to study the prevalence and diversity of Blastocystis in human populations (7-9). Emerging data from such studies have indicated that there is significant variation in the distribution of Blastocystis STs within and between geograp...

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Section: Figmentioning

confidence: 95%

Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population

Scanlan

Stensvold

Cotter

2015

Appl Environ Microbiol

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“…6,7 However, the pathogenicity of the infection is still controversial. Since, Blastocystis infection is associated with waterborne transmission 5,8 and is usually found in rural areas in the developing countries, 9 the infection may be a reflection of the poor sanitation of the communities. The study of epidemiology of Blastocystis infection will be helpful to further develop prevention and control efforts to reduce its morbidity among children.…”

Section: Introductionmentioning

confidence: 99%

Prevalence and Risk Factors for Blastocystis Infection Among Children and Caregivers in a Child Care Center, Bangkok, Thailand

Pipatsatitpong¹,

Leelayoova²,

Mungthin³

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. In September 2009, a cross-sectional study was conducted to evaluate parasitic infections in a child care center in Khlong Toei, Bangkok, Thailand. Of 503 children and staff members, 258 (51.3%) stool samples and questionnaires were obtained. The most common parasitic infection was Blastocystis sp. (13.6%). Blastocystis sp. subtype 3 was predominantly found (80.0%), followed by subtypes 2 (12

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“…Subtype analysis done on 51 clinical isolates has revealed a high prevalence of ST-4 (WR-1) among symptomatic patients from a health district of Valencia, Spain (7). ST-4 (WR-1) was revealed to be predominant in rural communities of Nepal and was also found to be common among Blastocystis-positive patients presenting with acute diarrhea in Denmark (71,72). Oral inoculation of rats with ST-4 (WR-1) resulted in mild goblet cell hyperplasia and significant upregulation of proinflammatory cytokines (21).…”

Section: Discussionmentioning

confidence: 99%

Differential Regulation of Proinflammatory Cytokine Expression by Mitogen-Activated Protein Kinases in Macrophages in Response to Intestinal Parasite Infection

et al. 2014

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Blastocystis is a common enteric protistan parasite that can cause acute, as well as chronic, infection and is associated with irritable bowel syndrome (IBS). However, the pathogenic status of Blastocystis infection remains unclear. In this study, we found that Blastocystis antigens induced abundant expression of proinflammatory cytokines, including interleukin 1␤ (IL-1␤), IL-6, and tumor necrosis factor alpha (TNF-␣), in mouse intestinal explants, in mouse colitis colon, and in macrophages. Further investigation utilizing RAW264.7 murine macrophages showed that Blastocystis treatment in RAW264.7 macrophages induced the activation of ERK, JNK, and p38, the three major groups of mammalian mitogen-activated protein (MAP) kinases that play essential roles in the expression of proinflammatory cytokines. ERK inhibition in macrophages significantly suppressed both mRNA and protein expression of IL-6 and TNF-␣ and mRNA expression of IL-1␤. On the other hand, JNK inhibition resulted in reductions in both c-Jun and ERK activation and significant suppression of all three proinflammatory cytokines at both the mRNA and protein levels. Inhibition of p38 suppressed only IL-6 protein expression with no effect on the expression of IL-1␤ and TNF-␣. Furthermore, we found that serine proteases produced by Blastocystis play an important role in the induction of ERK activation and proinflammatory cytokine expression by macrophages. Our study thus demonstrated for the first time that Blastocystis could induce the expression of various proinflammatory cytokines via the activation of MAP kinases and that infection with Blastocystis may contribute to the pathogenesis of inflammatory intestinal diseases through the activation of inflammatory pathways in host immune cells, such as macrophages.

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Predominance of Blastocystis sp. subtype 4 in rural communities, Nepal

Cited by 56 publications

References 40 publications

Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population

Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population

Prevalence and Risk Factors for Blastocystis Infection Among Children and Caregivers in a Child Care Center, Bangkok, Thailand

Differential Regulation of Proinflammatory Cytokine Expression by Mitogen-Activated Protein Kinases in Macrophages in Response to Intestinal Parasite Infection

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