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Sarzhanov F, Dogruman-Al F, Santin M, Maloney JG, Gureser AS, Karasartova D, Taylan-Ozkan A. Investigation of neglected protists Blastocystis sp. and Dientamoeba fragilis in immunocompetent and immunodeficient diarrheal patients using both conventional and molecular methods. PLoS Negl Trop Dis 2021; 15:e0009779. [PMID: 34613993 PMCID: PMC8494357 DOI: 10.1371/journal.pntd.0009779] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/30/2021] [Indexed: 02/07/2023] Open
Abstract
Introduction The clinical significance of Blastocystis sp. and Dientamoeba fragilis in patients with gastrointestinal symptoms is a controversial issue. Since the pathogenicity of these protists has not been fully elucidated, testing for these organisms is not routinely pursued by most laboratories and clinicians. Thus, the prevalence of these organisms and the subtypes of Blastocystis sp. in human patients in Turkey are not well characterized. This study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in the diarrheic stool samples of immunodeficient and immunocompetent patients using conventional and molecular methods and to identify Blastocystis sp. subtypes using next generation sequencing. Material and methods Individual stool specimens were collected from 245 immunodeficient and 193 immunocompetent diarrheic patients between March 2017 and December 2019 at the Gazi University Training and Research Hospital in Ankara, Turkey. Samples were screened for Blastocystis sp. and D. fragilis by conventional and molecular methods. Molecular detection of both protists was achieved by separate qPCRs targeting a partial fragment of the SSU rRNA gene. Next generation sequencing was used to identify Blastocystis sp. subtypes. Results The prevalence of Blastocystis sp. and D. fragilis was 16.7% and 11.9%, respectively as measured by qPCR. The prevalence of Blastocystis sp. and D. fragilis was lower in immunodeficient patients (12.7% and 10.6%, respectively) compared to immunocompetent patients (21.8% and 13.5%, respectively). Five Blastocystis sp. subtypes were identified and the following subtype distribution was observed: ST3 54.4% (n = 37), ST2 16.2% (n = 11), ST1 4.4% (n = 3), ST6 2.9% (n = 2), ST4 1.5% (n = 1), ST2/ST3 11.8% (n = 8) and ST1/ST3 8.8% (n = 6). There was no statistically significant difference in the distribution of Blastocystis sp. subtypes between immunocompetent and immunodeficient patients. Conclusion and recommendation Our findings demonstrated that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea. This study is the first to use next generation sequencing to address the presence of Blastocystis sp. mixed subtypes and intra-subtype variability in clinical samples in Turkey. Blastocystis sp. and Dientamoeba fragilis are single-cell parasites of the human intestine which are common worldwide and reported in cases with gastrointestinal symptoms. However, the role of Blastocystis sp. and D. fragilis in patients with gastrointestinal symptoms is still controversial because their presence is not always associated with symptoms. As some intestinal parasitic infections can cause severe illness in immunocompromised individuals careful consideration of intestinal protist infection is warranted. However, testing for Blastocystis sp. and D. fragilis is not routinely carried out by most laboratories and clinicians. Therefore, this study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in immunocompetent and immunosuppressed patients with diarrhea by conventional and molecular methods. Both Blastocystis sp. and D. fragilis were detected more frequently by quantitative polymerase chain reaction than by conventional methods. Next generation sequencing was used to characterize the diversity and frequency of Blastocystis sp. subtypes and mixed subtypes in patients in Turkey. Five Blastocystis sp. subtypes (ST1, ST2, ST3, ST4 and ST6) were detected. ST3 was the most frequent subtype in both immunocompetent and immunosuppressed patients. Mono-infections were more common than mixed subtype infections. Our findings showed that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea.
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Affiliation(s)
- Fakhriddin Sarzhanov
- Division of Medical Parasitology, Department of Medical Microbiology, School of Medicine, Gazi University, Ankara, Turkey
- Akhmet Yassawi International Kazakh-Turkish University, Faculty of Medicine, Turkestan, Kazakhstan
| | - Funda Dogruman-Al
- Division of Medical Parasitology, Department of Medical Microbiology, School of Medicine, Gazi University, Ankara, Turkey
- * E-mail: ,
| | - Monica Santin
- Environmental Microbial and Food Safety Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland, United States of America
| | - Jenny G. Maloney
- Environmental Microbial and Food Safety Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland, United States of America
| | - Ayse Semra Gureser
- Department of Medical Microbiology, School of Medicine, Hitit University, Corum, Turkey
| | - Djursun Karasartova
- Department of Medical Microbiology, School of Medicine, Hitit University, Corum, Turkey
| | - Aysegul Taylan-Ozkan
- Department of Medical Microbiology, School of Medicine, Hitit University, Corum, Turkey
- Department of Medical Microbiology, Faculty of Medicine, TOBB- University of Economics and Technology, Ankara, Turkey
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Wilcox JJS, Lopez-Cotto JJ, Hollocher H. Historical contingency, geography and anthropogenic patterns of exposure drive the evolution of host switching in the Blastocystis species-complex. Parasitology 2021; 148:985-993. [PMID: 33775262 PMCID: PMC11010051 DOI: 10.1017/s003118202100055x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/24/2021] [Accepted: 03/21/2021] [Indexed: 11/05/2022]
Abstract
Parasites have the power to impose significant regulatory pressures on host populations, making evolutionary patterns of host switching by parasites salient to a range of contemporary ecological issues. However, relatively little is known about the colonization of new hosts by parasitic, commensal and mutualistic eukaryotes of metazoans. As ubiquitous symbionts of coelomate animals, Blastocystis spp. represent excellent candidate organisms for the study of evolutionary patterns of host switching by protists. Here, we apply a big-data phylogenetic approach using archival sequence data to assess the relative roles of several host-associated traits in shaping the evolutionary history of the Blastocystis species-complex within an ecological framework. Patterns of host usage were principally determined by geographic location and shared environments of hosts, suggesting that weight of exposure (i.e. propagule pressure) represents the primary force for colonization of new hosts within the Blastocystis species-complex. While Blastocystis lineages showed a propensity to recolonize the same host taxa, these taxa were often evolutionarily unrelated, suggesting that historical contingency and retention of previous adaptions by the parasite were more important to host switching than host phylogeny. Ultimately, our findings highlight the ability of ecological theory (i.e. ‘ecological fitting’) to explain host switching and host specificity within the Blastocystis species-complex.
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Affiliation(s)
- Justin J. S. Wilcox
- Department of Biological Sciences, Galvin Life Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - John J. Lopez-Cotto
- Department of Biological Sciences, Galvin Life Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Hope Hollocher
- Department of Biological Sciences, Galvin Life Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Affiliation(s)
| | | | - C Graham Clark
- London School of Hygiene and Tropical Medicine, London, UK
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Lepczyńska M, Białkowska J, Dzika E, Piskorz-Ogórek K, Korycińska J. Blastocystis: how do specific diets and human gut microbiota affect its development and pathogenicity? Eur J Clin Microbiol Infect Dis 2017; 36:1531-1540. [PMID: 28326446 PMCID: PMC5554277 DOI: 10.1007/s10096-017-2965-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/08/2017] [Indexed: 12/31/2022]
Abstract
Blastocystis is an enteric parasite that inhabits the gastrointestinal tract of humans and many animals. This emerging parasite has a worldwide distribution. It is often identified as the most common eukaryotic organism reported in human fecal samples. This parasite is recognized and diagnosed more often than ever before. Furthermore, some strains develop resistance against currently recommended drugs, such as metronidazole; therefore, the use of natural remedies or special diets has many positive aspects that may address this problem. The goal of this review is to compare natural treatments and various diets against the efficacy of drugs, and describe their influence on the composition of the gut microbiota, which affects Blastocystis growth and the occurrence of symptoms. This article reviews important work in the literature, including the classification, life cycle, epidemiology, pathogenesis, pathogenicity, genetics, biology, and treatment of Blastocystis. It also includes a review of the current knowledge about human gut microbiota and various diets proposed for Blastocystis eradication. The literature has revealed that garlic, ginger, some medical plants, and many spices contain the most effective organic compounds for parasite eradication. They work by inhibiting parasitic enzymes and nucleic acids, as well as by inhibiting protein synthesis. The efficacy of any specific organic compound depends on the Blastocystis subtype, and, consequently, on its immunity to treatment. In conclusion, the article discusses the findings that human gut microbiota composition triggers important mechanisms at the molecular level, and, thus, has a crucial influence on the parasitic pathogenicity.
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Affiliation(s)
- M Lepczyńska
- Department of Medical Biology, Faculty of Medical Sciences, University of Warmia and Mazury, Żołnierska 14 C, Olsztyn, 10-561, Poland.
| | - J Białkowska
- Department of Neurology and Neurosurgery, Faculty of Medical Sciences, University of Warmia and Mazury, Warszawska 30, Olsztyn, Poland
| | - E Dzika
- Department of Medical Biology, Faculty of Medical Sciences, University of Warmia and Mazury, Żołnierska 14 C, Olsztyn, 10-561, Poland
| | - K Piskorz-Ogórek
- Department of Nursing, Faculty of Medical Sciences, University of Warmia and Mazury, Żołnierska 14 C, Olsztyn, Poland
- Regional Specialized Children's Hospital in Olsztyn, Żołnierska 18A, Olsztyn, Poland
| | - J Korycińska
- Department of Medical Biology, Faculty of Medical Sciences, University of Warmia and Mazury, Żołnierska 14 C, Olsztyn, 10-561, Poland
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Ajjampur SSR, Png CW, Chia WN, Zhang Y, Tan KSW. Ex Vivo and In Vivo Mice Models to Study Blastocystis spp. Adhesion, Colonization and Pathology: Closer to Proving Koch's Postulates. PLoS One 2016; 11:e0160458. [PMID: 27508942 PMCID: PMC4979897 DOI: 10.1371/journal.pone.0160458] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
Blastocystis spp. are widely prevalent extra cellular, non-motile anerobic protists that inhabit the gastrointestinal tract. Although Blastocystis spp. have been associated with gastrointestinal symptoms, irritable bowel syndrome and urticaria, their clinical significance has remained controversial. We established an ex vivo mouse explant model to characterize adhesion in the context of tissue architecture and presence of the mucin layer. Using confocal microscopy with tissue whole mounts and two axenic isolates of Blastocystis spp., subtype 7 with notable differences in adhesion to intestinal epithelial cells (IEC), isolate B (ST7-B) and isolate H (more adhesive, ST7-H), we showed that adhesion is both isolate dependent and tissue trophic. The more adhesive isolate, ST7-H was found to bind preferentially to the colon tissue than caecum and terminal ileum. Both isolates were also found to have mucinolytic effects. We then adapted a DSS colitis mouse model as a susceptible model to study colonization and acute infection by intra-caecal inoculation of trophic Blastocystis spp.cells. We found that the more adhesive isolate ST7-H was also a better colonizer with more mice shedding parasites and for a longer duration than ST7-B. Adhesion and colonization was also associated with increased virulence as ST7-H infected mice showed greater tissue damage than ST7-B. Both the ex vivo and in vivo models used in this study showed that Blastocystis spp. remain luminal and predominantly associated with mucin. This was further confirmed using colonic loop experiments. We were also successfully able to re-infect a second batch of mice with ST7-H isolates obtained from fecal cultures and demonstrated similar histopathological findings and tissue damage thereby coming closer to proving Koch’s postulates for this parasite.
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Affiliation(s)
- Sitara S. R. Ajjampur
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Chin Wen Png
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Wan Ni Chia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Yongliang Zhang
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
- * E-mail:
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Ragavan ND, Kumar S, Chye TT, Mahadeva S, Shiaw-Hooi H. Blastocystis sp. in Irritable Bowel Syndrome (IBS)--Detection in Stool Aspirates during Colonoscopy. PLoS One 2015; 10:e0121173. [PMID: 26375823 PMCID: PMC4572711 DOI: 10.1371/journal.pone.0121173] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/28/2015] [Indexed: 01/10/2023] Open
Abstract
Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. Its' association with IBS is controversial, possibly as a result of irregular shedding of parasites in stool and variation in stool detection. We aimed to screen for Blastocystis in colonic stool aspirate samples in adult patients with and without IBS undergoing colonoscopy for various indications and measure the interleukin levels (IL-8, IL-3 and IL-5). In addition to standard stool culture techniques, polymerase chain reaction (PCR) techniques were employed to detect and subtype Blastocystis. All the serum samples collected were subjected for ELISA studies to measure the interleukin levels (IL-8, IL-3 and IL-5). Among 109 (IBS n = 35 and non-IBS n = 74) adults, direct stool examination and culture of colonic aspirates were initially negative for Blastocystis. However, PCR analysis detected Blastocystis in 6 (17%) IBS and 4 (5.5%) non-IBS patients. In the six positive IBS patients by PCR method, subtype 3 was shown to be the most predominant (3/6: 50%) followed by subtype 4 (2/6; 33.3%) and subtype 5 (1/6; 16.6%). IL-8 levels were significantly elevated in the IBS Blasto group and IBS group (p<0.05) compared to non-IBS and non-IBS Blasto group. The level of IL-3 in were seen to be significantly higher in than IBS Blasto group and IBS group (p<0.05) compared to non-IBS. Meanwhile, the IL-5 levels were significantly higher in IBS Blasto group (p<0.05) compared to non-IBS and non-IBS Blasto group. This study implicates that detecting Blastosystis by PCR method using colonic aspirate samples during colonoscopy, suggests that this may be a better method for sample collection due to the parasite’s irregular shedding in Blastocystis-infected stools. Patients with IBS infected with parasite showed an increase in the interleukin levels demonstrate that Blastocystis does have an effect in the immune system.
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Affiliation(s)
- Nanthiney Devi Ragavan
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Suresh Kumar
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
- * E-mail:
| | - Tan Tian Chye
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Sanjiv Mahadeva
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ho Shiaw-Hooi
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
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Helenbrook WD, Shields WM, Whipps CM. Characterization of Blastocystis species infection in humans and mantled howler monkeys, Alouatta palliata aequatorialis, living in close proximity to one another. Parasitol Res 2015; 114:2517-25. [PMID: 25859926 DOI: 10.1007/s00436-015-4451-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 03/23/2015] [Indexed: 11/25/2022]
Abstract
This study characterizes Blastocystis species infections in humans and mantled howler monkeys, Alouatta palliata aequatorialis, living in close proximity to one another in northwestern Ecuador. Blastocystis species were identified from 58 of 96 (60.4 %) mantled howler monkey fecal samples, and 44 of 55 human fecal samples (81.5 %) by polymerase chain reaction. Using single-stranded conformation polymorphism, we were able to efficiently separate and sequence subtypes (STs) within mixed samples without the need for cloning. Blastocystis ST1, ST2, and ST3 were found in people, and two individuals were infected with more than one subtype. All monkey samples were ST8. The lack of shared subtypes between humans and monkeys suggests that no Blastocystis transmission occurs between these species in spite of close proximity in some instances. Based on analysis of demographic data from a questionnaire given to human participants, individuals who boiled their water before consumption were significantly less likely to be infected with Blastocystis (44.4 %) compared to those who did not (93.8 %) (p = 0.002). No other risk factors were significant, although hunters, females, individuals living in large families, and those living closer to forested habitat tended to have a higher proportion of Blastocystis infections.
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Affiliation(s)
- William D Helenbrook
- SUNY-ESF, State University of New York College of Environmental Science and Forestry, Environmental and Forest Biology, 1 Forestry Drive, Syracuse, NY, 13210, USA,
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Gaythri T, Suresh K, Subha B, Kalyani R. Identification and characterisation of heat shock protein 70 in thermal stressed Blastocystis sp. PLoS One 2014; 9:e95608. [PMID: 25180903 PMCID: PMC4151958 DOI: 10.1371/journal.pone.0095608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 03/28/2014] [Indexed: 12/02/2022] Open
Abstract
Protistan parasites in order to ensure their viability and demonstrate successful progression in their life cycle need to respond towards various environmental stressors. Blastocystis sp. is known to be the most commonly found intestinal protistan parasite in any human stool surveys and has been incriminated to be responsible for diarrhea and bloating stomach. The present study demonstrates for the first time the presence of HSP70 in subtypes of Blastocystis sp. when the cultures were subjected to temperature of 39 and 41 °C where the growth of parasites was reduced to a minimum to majority being granular forms. The growth of parasites exposed to higher temperatures however doubled compared to the controls when the parasites were re-cultured back at 37 °C. Upon thermal stress at 41 °C, subtype 3 and subtype 5 isolates' growth reached up to 2.97 × 10(6) and 3.05 × 10(6) cells/ml compared to their respective controlled culture tubes at 37 °C which peaked only at 1.34 × 10(6) and 1.70 × 10(6) cells/ml respectively. The designed primer set that amplified Blastocystis sp. subtype 7 HSP70 gene in subtypes 1, 3 and 5 was against a conserved region. The gene was amplified at 318 bp. The multiple sequence alignment showed that the targeted sequence length ranges from 291-295 bp. The pair wise alignment result showed that the sequence identity among the four sequence ranges from 88% to 96%. These findings were further evidenced by the up regulation of HSP70 gene in thermal stressed isolates of subtype 3 and 5 at 41 °C. Higher number of granular forms was significantly found in thermal stressed isolates of subtype 3 and 5 which implicates that this life cycle stage has a role in responding to thermal stress.
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Affiliation(s)
- T. Gaythri
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia
| | - K. Suresh
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia
| | - B. Subha
- Department of Genetics and Molecular Biology, University of Malaya, Kuala Lumpur, Malaysia
| | - R. Kalyani
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia
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Teo JDW, MacAry PA, Tan KSW. Pleiotropic effects of Blastocystis spp. Subtypes 4 and 7 on ligand-specific toll-like receptor signaling and NF-κB activation in a human monocyte cell line. PLoS One 2014; 9:e89036. [PMID: 24551212 PMCID: PMC3925187 DOI: 10.1371/journal.pone.0089036] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 01/19/2014] [Indexed: 12/23/2022] Open
Abstract
Blastocystis spp. is a common enteric stramenopile parasite that colonizes the colon of hosts of a diverse array of species, including humans. It has been shown to compromise intestinal epithelial cell barrier integrity and mediate the production of pro-inflammatory cytokines and chemokines. Mucosal epithelial surfaces, including the intestinal epithelium, are increasingly recognized to perform a vital surveillance role in the context of innate immunity, through the expression of pathogen recognition receptors, such as Toll-like receptors (TLRs). In this study, we use the human TLR reporter monocytic cell line, THP1-Blue, which expresses all human TLRs, to investigate effects of Blastocystis on TLR activation, more specifically the activation of TLR-2, -4 and -5. We have observed that live Blastocystis spp. parasites and whole cell lysate (WCL) alone do not activate TLRs in THP1-Blue. Live ST4-WR1 parasites inhibited LPS-mediated NF-κB activation in THP1-Blue. In contrast, ST7-B WCL and ST4-WR1 WCL induced pleiotropic modulation of ligand-specific TLR-2 and TLR-4 activation, with no significant effects on flagellin-mediated TLR-5 activation. Real time-qPCR analysis on SEAP reporter gene confirmed the augmenting effect of ST7-B on LPS-mediated NF-κB activation in THP1-Blue. Taken together, this is the first study to characterize interactions between Blastocystis spp. and host TLR activation using an in vitro reporter model.
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Affiliation(s)
- Joshua D. W. Teo
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Paul A. MacAry
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Program, National University of Singapore, Singapore, Singapore
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- * E-mail:
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Fedianina LV, Prodeus TV, Solov'eva OA. [Laboratory diagnosis of Blastocystis spp]. Med Parazitol (Mosk) 2012:52-58. [PMID: 23437730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Prodeus TV, Fedianina LV, Volkova IV. [Medical value of Blastocystis spp. infection]. Med Parazitol (Mosk) 2012:55-59. [PMID: 22536747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Abstract
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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Affiliation(s)
- Kevin S W Tan
- Department of Microbiology, Laboratory of Molecular and Cellular Parasitology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
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Puthia MK, Sio SWS, Lu J, Tan KSW. Blastocystis ratti induces contact-independent apoptosis, F-actin rearrangement, and barrier function disruption in IEC-6 cells. Infect Immun 2006; 74:4114-23. [PMID: 16790785 PMCID: PMC1489721 DOI: 10.1128/iai.00328-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Blastocystis is an enteric protozoan purportedly associated with numerous clinical cases of diarrhea, flatulence, vomiting, and other gastrointestinal symptoms. Despite new knowledge of Blastocystis cell biology, genetic diversity, and epidemiology, its pathogenic potential remains controversial. Numerous clinical and epidemiological studies either implicate or exonerate the parasite as a cause of intestinal disease. Therefore, the aim of this study was to investigate the pathogenic potential of Blastocystis by studying the interactions of Blastocystis ratti WR1, an isolate of zoonotic potential, with a nontransformed rat intestinal epithelial cell line, IEC-6. Here, we report that B. ratti WR1 induces apoptosis in IEC-6 cells in a contact-independent manner. Furthermore, we found that B. ratti WR1 rearranges F-actin distribution, decreases transepithelial resistance, and increases epithelial permeability in IEC-6 cell monolayers. In addition, we found that the effects of B. ratti on transepithelial electrical resistance and epithelial permeability were significantly abrogated by treatment with metronidazole, an antiprotozoal drug. Our results suggest for the first time that Blastocystis-induced apoptosis in host cells and altered epithelial barrier function might play an important role in the pathogenesis of Blastocystis infections and that metronidazole has therapeutic potential in alleviating symptoms associated with Blastocystis.
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Affiliation(s)
- Manoj K Puthia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore
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Abstract
Among the waterborne protozoan parasites of medical and veterinary importance, Blastocystis is perhaps one of the less well-understood. However, in recent years, there has been a surge of interest in the organism, fueled in part by the possible association of Blastocystis infection with intestinal disorders, and its unusual taxonomic affiliations. Although there is information on the parasite's morphology, taxonomy and mode of transmission, its pathogenicity, life cycle, and function of certain organelles continue to baffle investigators. The clinical relevance of Blastocystis will be better answered once an animal model is found. Blastocystis infections have a worldwide distribution but prevalence is highest in areas with poor hygiene and deficient sanitation services and facilities. Application of modern molecular tools has advanced knowledge of the organism's genetic diversity, taxonomy and zoonotic potential.
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Affiliation(s)
- Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, S 117597 Singapore, Singapore.
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Belova LM. [Blastocystis survival outside of the host organism]. Parazitologiia 1998; 32:180-3. [PMID: 9702798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Abstract
Bacteria-like endosymbionts were found in vacuolar cells and cysts of Blastocystis sp. from duck and monkey faecal material. The organisms ultrastructurally resembled Gram-negative bacilli, and were present in the nucleus of Blastocystis sp. from the duck and in the cytoplasm of Blastocystis sp. from the monkey. Based on size and differences in intracellular location, it is probable that these represent two distinct species of organisms.
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Affiliation(s)
- D J Stenzel
- Analytical Electron Microscopy Facility, Queensland University of Technology, Brisbane, Australia
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Affiliation(s)
- P F Boreham
- Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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