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Mohamed AM, Ahmed MA, Ahmed SA, Al-Semany SA, Alghamdi SS, Zaglool DA. Predominance and association risk of Blastocystis hominis subtype I in colorectal cancer: a case control study. Infect Agent Cancer 2017; 12:21. [PMID: 28413436 PMCID: PMC5389010 DOI: 10.1186/s13027-017-0131-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 04/06/2017] [Indexed: 01/15/2023] Open
Abstract
Background Blastocystis, a genetically diverse intestinal parasite with controversial pathogenic potential, has increasingly been incriminated for diarrheal illness in immunocompromised individuals including colorectal cancer (CRC) patients. The aim of the current study was to assess the possible association between Blastocystis infection and CRC condition in Makkah, Saudi Arabia (KSA). Methods Stool samples were collected from 80 non-cancer (NC) and 138 cancer subjects including 74 CRC patients and 64 patients with other cancers outside gastrointestinal tract (COGT). Molecularly confirmed Blastocystis isolates were genetically grouped and subtyped using multiplex polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) and sequence-tagged site primers-based PCR (PCR-STS), respectively. Results Blastocystis hominis were confirmed in 29.7, 25 and 15% among CRC, COGT and NC patients, respectively. Obtained Blastocystis isolates were initially categorized into 2 groups (A and C), which were subsequently subtyped into 3 different subtypes; subtype-I (38%), subtype-II (44%) and subtype-V (22%). Interestingly, subtype-I was the most predominantly detected subtype (54.5%) among CRC patients with a significant association risk (COR 7.548; 95% CI: 1.629–34.987; P = 0.004). Conclusion To the best of our knowledge, the current study is the first to provide genetic insights on the prevalence of Blastocystis hominis among CRC patients in Makkah, KSA. Moreover, the study suggests for a possible association between subtype-I of Blastocystis hominis and CRC, which could indicate a potential influence of Blastocystis on CRC condition. Further studies are required to confirm this association risk and to investigate the possible underlying mechanism of postulated carcinogenic influence of Blastocystis hominis subtype-I. Electronic supplementary material The online version of this article (doi:10.1186/s13027-017-0131-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amr Mohamed Mohamed
- Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, 7607 Saudi Arabia.,Clinical Laboratory Diagnosis, Department of Animal Medicine, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Mona Abdelfattah Ahmed
- Medical Parasitology, King Abdullah Medical City, Makkah, Saudi Arabia.,Parasitology Department, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
| | | | - Sherif Ahmed Al-Semany
- Oncology, King Abdullah Medical City, Makkah, Saudi Arabia.,Department of Internal Medicine, Medical Oncology, Mansoura University, Mansoura, Egypt
| | - Saad Saed Alghamdi
- Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, 7607 Saudi Arabia
| | - Dina Abdulla Zaglool
- Medical Parasitology, Al-Noor Specialist Hospital, Makkah, Saudi Arabia.,Parasitology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
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52
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Khademvatan S, Masjedizadeh R, Yousefi-Razin E, Mahbodfar H, Rahim F, Yousefi E, Foroutan M. PCR-based molecular characterization of Blastocystis hominis subtypes in southwest of Iran. J Infect Public Health 2017; 11:43-47. [PMID: 28404232 DOI: 10.1016/j.jiph.2017.03.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/06/2017] [Accepted: 03/25/2017] [Indexed: 01/02/2023] Open
Abstract
Blastocystis hominis is the most common intestinal parasite found in humans and many other hosts. Pathogenicity of Blastocystis sp. remains controversial and it has been suggested that it may be associated with certain subtypes of organism. The aim of this study was to evaluate the molecular epidemiology of B. hominis and its subtype distribution in Ahvaz, southwest of Iran. During 2012-2014, a total of 481 samples were collected from patients referred to the medical laboratory centers in Ahvaz for stool examination. Samples were examined by wet mount, and genomic DNA was extracted from 50 positive samples. PCR was performed using seven primer pairs targeting the SSU rDNA gene and sequenced. 69 (14.35%) samples were found to be positive for B. hominis and the subtypes of 50 samples were identified. Five subtypes (STs) were identified, including: ST1 (22%), ST2 (6%), ST3 (40%), ST4 (2%), and ST5 (8%). 11 (22%) mixed infections were found, of which 5 were a mixture of ST3/ST4. Mixtures of ST1/ST3 and ST1/ST4 were 3, respectively. In this study people infected with ST3 showed the most gastrointestinal symptoms. This is the first study in the population of Ahvaz and indicates the high prevalence of ST3 in this area. The results suggest a possible association between this subtype and pathogenic potential of parasite.
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Affiliation(s)
- Shahram Khademvatan
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Medical Parasitology and Mycology & Cellular and Molecular Research Center, Urmia University of Medical Sciences, Urmia, Iran
| | - Rahim Masjedizadeh
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ehsan Yousefi-Razin
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, and Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamidreza Mahbodfar
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Fakher Rahim
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
| | - Elham Yousefi
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Masoud Foroutan
- Research Institute for Infectious Diseases of Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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53
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Inter- and intra-subtype variation of Blastocystis subtypes isolated from diarrheic and non-diarrheic patients in Iran. INFECTION GENETICS AND EVOLUTION 2017; 50:77-82. [PMID: 28238960 DOI: 10.1016/j.meegid.2017.02.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 12/24/2022]
Abstract
Blastocystis is a common intestinal parasitic protist infecting birds and mammals. Blastocystis comprises at least 17 subtypes (ST), of which ST1-ST9 have been detected in humans. Significant correlation between certain subtypes and pathogenicity remains to be established. Nevertheless, some studies suggest a potential linkage between subtypes (inter- and intra-subtype variation) and clinical manifestations. The aim of this study was to identify intra-subtype genetic variation of subtypes of Blastocystis in stools samples submitted by diarrheic and non-diarrheic patients. A 550-bp fragment of the nuclear small subunit ribosomal rRNA gene was amplified from 58 culture-positive samples isolated from diarrheic and non-diarrheic Iranian patients. PCR products were sequenced and sequences subjected to phylogenetic analysis. Intra-and inter-subtype variation was calculated. Based on comparison with reference sequences in GenBank, ST1, ST2 and ST3 were found in 18 (31.03%), 21 (36.22%), and 19 (32.75%) of the samples, respectively. Diarrheic stools were observed in eight (44.44%), 10 (47.61%), and nine (47.36%) patients with ST1, ST2, and ST3, respectively. No statistically significant correlation was found between subtypes and diarrhea (P=1.000). Multiple sequence alignment exhibited a within-subtype similarity of 98.76%, 97.17%, and 99.78% in ST1, ST2, and ST3, respectively. Highest similarity was seen among ST3 isolates, while lowest similarity was seen among ST2 isolates. Phylogenetic analysis did not suggest any correlation between diarrhea and intra-subtype variation. Inter- and intra-subtype variation in SSU rRNA gene appears not to reflect differences in the clinical outcome of Blastocystis carriage.
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54
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Ramírez JD, Flórez C, Olivera M, Bernal MC, Giraldo JC. Blastocystis subtyping and its association with intestinal parasites in children from different geographical regions of Colombia. PLoS One 2017; 12:e0172586. [PMID: 28222192 PMCID: PMC5319748 DOI: 10.1371/journal.pone.0172586] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 02/07/2017] [Indexed: 11/18/2022] Open
Abstract
Blastocystis is a common enteric protist colonizing probably more than 1 billion people with a large variety of non-human hosts. Remarkable genetic diversity has been observed, leading to the subdivision of the genus into multiple subtypes (ST), some of which are exclusively found in non-human hosts. The aim of this study was to determine the distribution of Blastocystis STs/18S alleles in symptomatic (abdominal pain, anal pruritus, diarrhea, headache, nauseas and/or vomit) and asymptomatic children from nine geographical regions of Colombia. A total of 2026 fecal samples were collected as part of a national survey to estimate the frequency of intestinal parasites in children. A set of 256 samples that were Blastocystis positive was finally selected. The samples were submitted to DNA extraction, Real Time PCR and sequencing using Blastocystis-specific primers targeting the small subunit rRNA gene for ST identification. DNA of Ascaris lumbricoides (16.4%), Trichuris trichiura (8.2%), hookworms (Necator americanus/Ancylostoma duodenale) (7.3%), Giardia duodenalis (23.1%), Entamoeba complex (82%), Entamoeba coli (55%), Hymenolepis nana (0.8%), Endolimax nana (33.2%) and Neobalantidium coli (2.7%) was detected in the Blastocystis-positive samples. We detected ST1 (21.4%), ST2 (19.5%), ST3 (55.5%), ST4 (0.8%), ST6 (2%) and ST7 (0.8%); alleles 1, 2, 4, 81, 82 and 83 for ST1; alleles 9, 11, 12, 15, 67, 71 and 73 for ST2; alleles 34, 36, 38, 45, 49, 55, 134 and 128 for ST3; allele 42 for ST4; allele 122 for ST6, and allele 142 for ST7. Further studies implementing high-resolution molecular markers are necessary to understand the dynamics of Blastocystis transmission and the role of this Stramenopila in health and disease.
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MESH Headings
- Adolescent
- Alleles
- Asymptomatic Diseases
- Blastocystis/classification
- Blastocystis/genetics
- Blastocystis Infections/epidemiology
- Blastocystis Infections/parasitology
- Child
- Child, Preschool
- Coinfection
- Colombia/epidemiology
- DNA Barcoding, Taxonomic
- DNA, Protozoan/analysis
- DNA, Protozoan/isolation & purification
- DNA, Ribosomal/analysis
- DNA, Ribosomal/isolation & purification
- Feces/parasitology
- Female
- Genetic Variation
- Geography, Medical
- Health Surveys
- Humans
- Intestinal Diseases, Parasitic/parasitology
- Male
- RNA, Protozoan/genetics
- RNA, Ribosomal, 18S/genetics
- Real-Time Polymerase Chain Reaction
- Ribotyping
- Species Specificity
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Affiliation(s)
- Juan David Ramírez
- Grupo de Investigaciones Microbiológicas – UR (GIMUR), Programa de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá – Colombia
- * E-mail:
| | - Carolina Flórez
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá – Colombia
| | - Mario Olivera
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá – Colombia
| | - María Consuelo Bernal
- Programa profesional de Biología, Grupo de Investigación en Parasitología y Microbiología tropical – GIPAMT, Universidad Incca de Colombia, Bogotá – Colombia
| | - Julio Cesar Giraldo
- Programa profesional de Biología, Grupo de Investigación en Parasitología y Microbiología tropical – GIPAMT, Universidad Incca de Colombia, Bogotá – Colombia
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55
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Del Coco VF, Molina NB, Basualdo JA, Córdoba MA. [Blastocystis spp.: Advances, controversies and future challenges]. Rev Argent Microbiol 2017; 49:110-118. [PMID: 28189279 DOI: 10.1016/j.ram.2016.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/09/2016] [Accepted: 08/29/2016] [Indexed: 01/24/2023] Open
Abstract
Blastocystis spp. is the most common protozoan detected in human stool samples. In developing countries, infection rates are higher than 20%. The presence of this parasite in the feces of several host species suggests its zoonotic potential. The clinical relevance and the pathogenic role of Blastocystis spp. in the intestinal tract remain unclear. There are several clinical reports that recognize it as the etiologic agent of several intestinal disorders such as diarrhea, inflammatory bowel disease and ulcerative colitis, although the pathogenicity of this parasite has not been proved yet. This wide range of clinical manifestations could be related to the genetic diversity exhibited by this parasite.
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Affiliation(s)
- Valeria F Del Coco
- Centro Universitario de Estudios Microbiológicos y Parasitológicos, Sede Cátedra de Microbiología y Parasitología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina.
| | - Nora B Molina
- Centro Universitario de Estudios Microbiológicos y Parasitológicos, Sede Cátedra de Microbiología y Parasitología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Juan A Basualdo
- Centro Universitario de Estudios Microbiológicos y Parasitológicos, Sede Cátedra de Microbiología y Parasitología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María A Córdoba
- Centro Universitario de Estudios Microbiológicos y Parasitológicos, Sede Cátedra de Microbiología y Parasitología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina; Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina
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56
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Büyükbaba Boral Ö, Çelik Payçu DG, Akgül A, İşsever H. Blastocystis spp. Saptanan 50 Semptomatik Hastada Subtip Dağılımın Saptanması. KOCAELI ÜNIVERSITESI SAĞLIK BILIMLERI DERGISI 2017. [DOI: 10.30934/kusbed.359174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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57
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Yersal O, Malatyali E, Ertabaklar H, Oktay E, Barutca S, Ertug S. Blastocystis subtypes in cancer patients: Analysis of possible risk factors and clinical characteristics. Parasitol Int 2016; 65:792-796. [DOI: 10.1016/j.parint.2016.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/24/2016] [Accepted: 02/18/2016] [Indexed: 10/22/2022]
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58
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Dogan N, Aydin M, Tuzemen NU, Dinleyici EC, Oguz I, Dogruman-Al F. Subtype distribution of Blastocystis spp. isolated from children in Eskisehir, Turkey. Parasitol Int 2016; 66:948-951. [PMID: 27989831 DOI: 10.1016/j.parint.2016.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 09/04/2016] [Accepted: 10/17/2016] [Indexed: 12/11/2022]
Abstract
Blastocystis spp. is the most common enteric protist found in human feces. The pathogenic role of Blastocystis remains controversial and it has been suggested that the symptomatology of Blastocystis is associated with its subtypes (ST). However, only few studies have investigated the relationship between the symptomatology and subtypes of Blastocystis in children. This study aimed to investigate the prevalence of Blastocystis in children aged 3 to 13years with or without gastrointestinal complaints and determine the distribution of the subtypes of Blastocystis. A total of 303 stool samples obtained from symptomatic (n=84) and asymptomatic (n=219) children were included in the study. The presence of Blastocystis was investigated using native-lugol examination, trichrome staining and real-time PCR method. Using the real-time PCR method, 115 samples were found positive for Blastocystis. Subtyping was successfully performed on 46 samples using sequenced-tagged site (STS) primers and PCR. The remaining 69 samples could not be subtyped. The most frequently detected subtype was ST3 (43.4%) followed by ST1 (26.1%), ST4 (10.9%) and ST2 (8.7%). The mixed subtypes were identified in five samples (10.9%) as; ST1+ST3 (n=3), ST1+ST2 (n=1) and ST2+ST3 (n=1). None of the samples had ST5, ST6 or ST7. No statistically significant difference was found between the symptomatic and asymptomatic groups in terms of the Blastocystis positivity and the distribution of subtypes (p>0.05). To our knowledge, this is the first study to investigate the subtype distribution of Blastocystis in children in Turkey and the results are in agreement with the related data available in Turkey.
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Affiliation(s)
- Nihal Dogan
- Department of Medical Microbiology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey.
| | - Merve Aydin
- Department of Medical Microbiology, Faculty of Medicine, Erzincan University, Erzincan, Turkey
| | - Nazmiye Ulku Tuzemen
- Department of Medical Microbiology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Ener Cagri Dinleyici
- Department of Pediatric Intensive Care, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Ilkiz Oguz
- Department of Medical Microbiology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Funda Dogruman-Al
- Department of Medical Microbiology, Faculty of Medicine, Gazi University, Ankara, Turkey
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59
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Noradilah SA, Lee IL, Anuar TS, Salleh FM, Abdul Manap SNA, Mohd Mohtar NSH, Azrul SM, Abdullah WO, Moktar N. Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia. PeerJ 2016; 4:e2541. [PMID: 27761331 PMCID: PMC5068341 DOI: 10.7717/peerj.2541] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/07/2016] [Indexed: 12/27/2022] Open
Abstract
In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the transmission of Blastocystis sp. to humans and animals in this aboriginal community.
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Affiliation(s)
- Samseh Abdullah Noradilah
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia Medical Centre, Cheras, Kuala Lumpur, Malaysia; Faculty of Medicine and Health Sciences, Universiti Sains Islam Malaysia, Pandan Indah, Kuala Lumpur, Malaysia
| | - Ii Li Lee
- Kulliyyah of Medicine and Health Sciences, Kolej Universiti Insaniah , Kuala Ketil , Kedah , Malaysia
| | - Tengku Shahrul Anuar
- Department of Medical Laboratory Technology, Universiti Teknologi MARA, Puncak Alam, Selangor, Malaysia; Integrative Pharmacogenomics Institute, Universiti Teknologi MARA, Puncak Alam Campus, Bandar Puncak Alam, Selangor, Malaysia
| | - Fatmah Md Salleh
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia Medical Centre , Cheras , Kuala Lumpur , Malaysia
| | - Siti Nor Azreen Abdul Manap
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia Medical Centre , Cheras , Kuala Lumpur , Malaysia
| | - Noor Shazleen Husnie Mohd Mohtar
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia Medical Centre , Cheras , Kuala Lumpur , Malaysia
| | - Syed Muhamad Azrul
- Multipurpose Laboratory, Universiti Kebangsaan Malaysia Medical Centre , Cheras , Kuala Lumpur , Malaysia
| | - Wan Omar Abdullah
- Faculty of Medicine and Health Sciences, Universiti Sains Islam Malaysia , Pandan Indah , Kuala Lumpur , Malaysia
| | - Norhayati Moktar
- Department of Parasitology and Medical Entomology, Universiti Kebangsaan Malaysia Medical Centre , Cheras , Kuala Lumpur , Malaysia
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60
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Prevalence and Genotype Analysis of Blastocystis hominis in Iran: A Systematic Review and Meta-Analysis. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2016. [DOI: 10.5812/archcid.36648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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61
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Kiani H, Haghighi A, Rostami A, Azargashb E, Tabaei SJS, Solgi A, Zebardast N. PREVALENCE, RISK FACTORS AND SYMPTOMS ASSOCIATED TO INTESTINAL PARASITE INFECTIONS AMONG PATIENTS WITH GASTROINTESTINAL DISORDERS IN NAHAVAND, WESTERN IRAN. Rev Inst Med Trop Sao Paulo 2016; 58:42. [PMID: 27253744 PMCID: PMC4879999 DOI: 10.1590/s1678-9946201658042] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/30/2015] [Indexed: 01/22/2023] Open
Abstract
We studied the prevalence of intestinal parasites (IPs), their risk factors and associated symptoms among patients with gastrointestinal disorders. A total of 1,301 participants aged 22 days-90 years were enrolled in this study. We used a structured questionnaire to obtain socio-demographic and stool examination to investigate intestinal parasite infections. Data analysis was performed using SPSS16. The overall prevalence of intestinal parasites (IPs) was 32.2% (419/1,301). Three hundred and fifty nine cases/1,301 (27.6%) were infected with a single parasite and 60/1,301 cases (4.6%) presented polyparasitism. The most common IP was Blastocystis sp. 350/1,301 (26.9%), followed by Entamoeba coli 38/1,301 (2.92%), Giardia lamblia 30/1,301 (2.3%) and Cryptosporidium spp. 17/1,301 (1.3%). Regarding the socio-demographic variables, educational status (p = 0.001), contact with domestic animals and soil (p = 0.02), age above 15 years (p = 0.001) and seasons (p = 0.001) were significantly associated to intestinal parasitic infections. Concerning clinical characteristics, the presence of IPs was significantly associated to diarrhea (OR = 1.57; CI 95% = 1.24-1.98; p < 0.001) and dysentery (OR = 1.94; CI 95% = 1.03-3.66; p < 0.04). Our findings suggest that IPs are one of the main causal agents of gastrointestinal disorders. Improving the knowledge on local risk factors such as poverty, low level of education, poor sanitation, contact with soil and contact with domestic animal is warranted.
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Affiliation(s)
- Hamed Kiani
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, , , , ,
| | - Ali Haghighi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, , , , ,
| | - Ali Rostami
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, , , , ,
| | | | | | - Abbas Solgi
- School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran,
| | - Nozhat Zebardast
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, , , , ,
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62
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Yoshikawa H, Iwamasa A. Human Blastocystis subtyping with subtype-specific primers developed from unique sequences of the SSU rRNA gene. Parasitol Int 2016; 65:785-791. [PMID: 26965391 DOI: 10.1016/j.parint.2016.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 02/23/2016] [Accepted: 03/06/2016] [Indexed: 11/15/2022]
Abstract
The genus Blastocystis is one of the most genetically diverse parasites. Blastocystis isolates from humans and animals have been classified into subtypes (STs) based on the phylogeny of the small subunit rRNA gene (SSU rDNA). Although human Blastocystis isolates are limited to STs 1-9, the identification of all 9 STs remains challenging due to the lack of specific primers for several STs. The sequencing of partial SSU rDNA is therefore essential for the identification of several STs. In this study, we developed 9 sets of PCR primers to detect each of the 9 kinds of ST in humans. When these ST-specific primer pairs were examined reference Blastocystis for the 9 STs, all 9 amplified only the target ST even in a DNA mixture of all 9 STs. The specificities of the 9 primer sets were tested against several intestinal parasites and fungi found in human stool samples. No amplification with these common human intestinal eukaryotes was observed using the primer pairs for 8 STs, while the ST5 primer set gave only faint bands with some parasites. Since genomic DNA levels of these parasites extracted from Blastocystis-positive cultures are expected to be markedly lower than the pure or highly concentrated DNA samples tested, the cross-amplifications with these organisms are unlikely to be detected when DNA samples are extracted from Blastocystis-positive cultures. The PCR conditions for all 9 primer sets were the same, hence a one-step analysis by PCR amplification, followed by electrophoresis has potential as a simple tool for the subtyping of human Blastocystis isolates.
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Affiliation(s)
- Hisao Yoshikawa
- Department of Biological Science, Faculty of Sciences, Nara Women's University, Kitauoya-Nishimachi, Nara 630-8506, Japan; Department of Biological Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoya-Nishimachi, Nara 630-8506, Japan.
| | - Ayana Iwamasa
- Department of Biological Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoya-Nishimachi, Nara 630-8506, Japan
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Kurt Ö, Doğruman Al F, Tanyüksel M. Eradication of Blastocystis in humans: Really necessary for all? Parasitol Int 2016; 65:797-801. [PMID: 26780545 DOI: 10.1016/j.parint.2016.01.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/30/2015] [Accepted: 01/14/2016] [Indexed: 02/01/2023]
Abstract
Blastocystis (initially named as Blastocystis hominis) has long been known as a protist without any clinical significance. However, there is now a huge pile of case reports where Blastocystis is blamed for the symptoms and the infection described in the patients. Introduction of the presence of as many as 17 Blastocystis subtypes while many infected individuals are non-symptomatic initially brought about the correlation between the subtypes and pathogenicity; however, the outcomes of these trials were not consistent and did not explain its pathogenicity. Today, it is mostly acknowledged that Blastocystis may colonize many individuals but the infection's onset depends on the interaction between the virulence of parasites and host's immune competence. Eradication of Blastocystis is essential in some cases where it is the only infectious agent and patient is suffering from some symptoms. In such cases, metronidazole is the drug of choice but its efficacy is relatively low in some cases. Other agents used include trimethoprim-sulfamethoxazole, paromomycin, and furazolidone. Recent studies on the interactions between human health and the role of gut microbiota introduces new data which may significantly change our point of view against some protists, which we tend to see as "parasites requiring urgent eradication for cure". May the presence or absence of some Blastocystis subtypes necessary for human health, or is the absence or presence of certain Blastocystis subtypes in human gut is associated with certain diseases/infections? The answers of these questions will surely guide us to select patients requiring treatment against Blastocystis infection in future.
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Affiliation(s)
- Özgür Kurt
- Faculty of Medicine, Department of Medical Microbiology, Acibadem University, Istanbul, Turkey.
| | - Funda Doğruman Al
- Faculty of Medicine, Department of Medical Microbiology, Gazi University, Ankara, Turkey.
| | - Mehmet Tanyüksel
- Faculty of Medicine, Department of Medical Microbiology, Gülhane Military Medical Academy, Ankara, Turkey.
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Khoshnood S, Rafiei A, Saki J, Alizadeh K. Prevalence and Genotype Characterization of Blastocystis hominis Among the Baghmalek People in Southwestern Iran in 2013 - 2014. Jundishapur J Microbiol 2015; 8:e23930. [PMID: 26587213 PMCID: PMC4644266 DOI: 10.5812/jjm.23930] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/30/2015] [Accepted: 02/16/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Blastocystis hominis is a common globally distributed parasite. The prevalence of this parasite has been shown to vary among different countries. Molecular studies have also shown that there is a high level of genetic diversity among Blastocystis spp. isolated from humans and animals. Extensive information on parasitic genotypes will aid in devising more effective strategies for the identification and potential control of these pathogenic parasites. OBJECTIVES This study aimed to gain information on the prevalence and abundance of Blastocystis subtypes in Iran. MATERIALS AND METHODS Over a period of 3 months, 1,410 stool samples were collected and examined by microscopy. Samples found to be positive for B. hominis were concentrated and phylogenetic analysis was subsequently performed. A questionnaire was completed by all study participants. RESULTS Blastocystis hominis was found to have a prevalence of 3.33% in the study population. There was no significant association of Blastocystis infection with age (P = 0.3) or gender (P = 0.57). The Blastocystis subtypes (ST) identified in this study were ST3, ST4, ST5, and ST7 with the most prevalent being ST4 (40.9%). CONCLUSIONS The prevalence of B. hominis in the study area was lower than that reported for most developed countries, and unlike in other countries in the Middle East, ST4 was the most prevalent subtype.
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Affiliation(s)
- Saleh Khoshnood
- Parasitology Department, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran
| | - Abdollah Rafiei
- Parasitology Department, Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran
| | - Jasem Saki
- Parasitology Department, Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran
| | - Kobra Alizadeh
- Department of Occupational Health, Faculty of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran
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Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population. Appl Environ Microbiol 2015; 81:4071-6. [PMID: 25841010 DOI: 10.1128/aem.00520-15] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 03/31/2015] [Indexed: 01/01/2023] Open
Abstract
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.
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Badparva E, Sadraee J, Kheirandish F. Genetic diversity of blastocystis isolated from cattle in khorramabad, iran. Jundishapur J Microbiol 2015; 8:e14810. [PMID: 25964846 PMCID: PMC4417945 DOI: 10.5812/jjm.14810] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 11/16/2022] Open
Abstract
Background: Blastocystis is a zoonotic protozoan parasite living in the digestive system of some vertebrates. This parasite has some subtypes, pathogenicity status of which has still remained controversial. Objectives: The aim of this study was to determine the subtype of Blastocystis in infected cattle. Materials and Methods: This descriptive cross-sectional study was performed on 196 isolates from cattle stool samples collected from slaughterhouse in Khorramabad city, Iran, in 2012. Genomic DNA was extracted and to determine the Blastocystis subtype, seven pairs of sequence-tagged sites (STS) primers were used. Results: Of 196 specimens, 19 (9.6%) were infected with Blastocystis. Among the 19 positive samples, the most common subtype was ST5 (47.36 %), followed by ST3 (10.53%) and ST6 (10.53%). Two (10.53%) samples had mixed infections by ST3 and ST5. The four isolates not amplified by any STS primers were probably unknown genotypes. Conclusions: In the present study, the highest prevalence was for ST5, which is so important for epidemiology and risk of human infection. The report related to ST3 in cattle as a subtype of human showed mutual infection between human and cattle. Another important point in this study was the ST6 report. Finally, it seems that gathering epidemiological data is needed for a better understanding of the potential animal reservoirs for human infection.
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Affiliation(s)
- Ebrahim Badparva
- Department of Parasitology and Mycology, Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, IR Iran
| | - Javid Sadraee
- Department of Parasitology, Tarbiat Modares University, Tehran, IR Iran
| | - Farnaz Kheirandish
- Department of Parasitology and Mycology, Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, IR Iran
- Corresponding author: Farnaz Kheirandish, Department of Parasitology and Mycology, Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, P. O. Box: 381351698, Khorramabad, IR Iran. Tel/Fax: +98-6616200133, E-mail:
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Wawrzyniak I, Poirier P, Viscogliosi E, Dionigia M, Texier C, Delbac F, Alaoui HE. Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis. Ther Adv Infect Dis 2014; 1:167-78. [PMID: 25165551 DOI: 10.1177/2049936113504754] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
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 30-60% 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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Affiliation(s)
- Ivan Wawrzyniak
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France
| | - Philippe Poirier
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand, CNRS, UMR 6023, LMGE, Aubière, Clermont Université, Université d'Auvergne, JE 2526, Evolution des bactéries pathogènes et susceptibilité de l'hôte, Clermont-Ferrand and CHU Clermont-Ferrand, Service Parasitologie Mycologie, Clermont-Ferrand, France
| | - Eric Viscogliosi
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, Biology and Diversity of Emerging Eukaryotic Pathogens, Lille cedex, France
| | - Meloni Dionigia
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, Biology and Diversity of Emerging Eukaryotic Pathogens, Lille cedex, France and Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center 3-1-1 Koyadai, Tsukuba-shi, Ibaraki, Japan
| | - Catherine Texier
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France
| | - Frédéric Delbac
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Clermont-Ferrand and CNRS, UMR 6023, LMGE, Aubière, France
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El Safadi D, Gaayeb L, Meloni D, Cian A, Poirier P, Wawrzyniak I, Delbac F, Dabboussi F, Delhaes L, Seck M, Hamze M, Riveau G, Viscogliosi E. Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide. BMC Infect Dis 2014; 14:164. [PMID: 24666632 PMCID: PMC3987649 DOI: 10.1186/1471-2334-14-164] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 03/19/2014] [Indexed: 02/09/2024] Open
Abstract
Background Blastocystis sp. is currently the most common intestinal protist found in human feces and considered an emerging parasite with a worldwide distribution. Because of its potential impact in public health, we reinforced the picture of Blastocystis sp. prevalence and molecular subtype distribution in Africa by performing the first survey of this parasite in Senegal. Methods Stool samples from 93 symptomatic presenting with various gastrointestinal disorders or asymptomatic children living in three villages of the Senegal River Basin were tested for the presence of Blastocystis sp. by non-quantitative and quantitative PCR using primer pairs targeting the SSU rDNA gene. Positive samples were subtyped to investigate the frequency of Blastocystis sp. subtypes in our cohort and the distribution of subtypes in the symptomatic and asymptomatic groups of children. Results By the use of molecular tools, all 93 samples were found to be positive for Blastocystis sp. indicating a striking parasite prevalence of 100%. Mixed infections by two or three subtypes were identified in eight individuals. Among a total of 103 subtyped isolates, subtype 3 was most abundant (49.5%) followed by subtype 1 (28.2%), subtype 2 (20.4%) and subtype 4 (1.9%). Subtype 3 was dominant in the symptomatic group while subtypes 1 and 2 were detected with equal frequency in both symptomatic and asymptomatic groups. The distribution of subtypes was compared with those available in other African countries and worldwide. Comparison confirmed that subtype 4 is much less frequently detected or absent in Africa while it is commonly found in Europe. Potential sources of Blastocystis sp. infection including human-to-human, zoonotic, and waterborne transmissions were also discussed. Conclusions The prevalence of Blastocystis sp. in our Senegalese population was the highest prevalence ever recovered worldwide for this parasite by reaching 100%. All cases were caused by subtypes 1, 2, 3 and 4 with a predominance of subtype 3. More than half of the children infected by Blastocystis sp. presented various gastrointestinal disorders. Such high prevalence of blastocystosis in developing countries makes its control a real challenge for public health authorities.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Eric Viscogliosi
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille (CIIL), Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, 1 rue du Professeur Calmette, BP 245, 59019 Lille cedex, France.
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69
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Zanzani S, Epis S, Bandi C, Manfredi MT. What is your diagnosis? Fecal smear stained with Lugol's solution and Giemsa from a cynomolgus macaque (Macaca fascicularis) presenting with liquid diarrhea. Vet Clin Pathol 2014; 43:293-4. [DOI: 10.1111/vcp.12128] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Sergio Zanzani
- Department of Veterinary Science and Public Health; Università degli Studi di Milano; Milan Italy
| | - Sara Epis
- Department of Veterinary Science and Public Health; Università degli Studi di Milano; Milan Italy
| | - Claudio Bandi
- Department of Veterinary Science and Public Health; Università degli Studi di Milano; Milan Italy
| | - Maria T. Manfredi
- Department of Veterinary Science and Public Health; Università degli Studi di Milano; Milan Italy
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Rajamanikam A, Govind SK. Amoebic forms of Blastocystis spp. - evidence for a pathogenic role. Parasit Vectors 2013; 6:295. [PMID: 24499467 PMCID: PMC3853151 DOI: 10.1186/1756-3305-6-295] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 10/03/2013] [Indexed: 01/08/2023] Open
Abstract
Background Blastocystis spp. are one of the most prevalent parasites isolated from patients suffering from diarrhea, flatulence, constipation and vomiting. It’s pathogenicity and pathophysiology remains controversial to date. Protease activity and amoebic forms have been reported previously in symptomatic isolates but there has been no conclusive evidence provided to correlate the protease activity and any specific life cycle stage of the parasite thus far. Methods Symptomatic isolates with amoebic form were tested for protease activity and compared with symptomatic and asymptomatic isolates without amoebic form for 10 days culture period. Results The present study demonstrates an elevated protease activity in cultures having a higher percentage of amoebic forms seen in symptomatic isolates. The growth curve demonstrated a significantly (p < 0.05) higher average number of parasite counts in asymptomatic compared to symptomatic isolates. Symptomatic isolates showed amoebic forms with percentages ranging from 5% to 17%. Elevated protease activity was demonstrated in isolates that had higher percentages of amoebic forms with intense bands at higher molecular weight proteases (60 – 100 kDa). As days of culture proceeded, the protease quantification also showed a steady increase. Conclusion This study elucidates a correlation between protease activity and percentage of amoebic forms. The finding implies that these forms could play a role in exacerbation of intestinal symptoms during Blastocystis spp. infection.
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Affiliation(s)
| | - Suresh Kumar Govind
- Department of Parasitology, University of Malaya, Kuala Lumpur 50603, Malaysia.
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71
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Stensvold CR. Blastocystis: Genetic diversity and molecular methods for diagnosis and epidemiology. Trop Parasitol 2013; 3:26-34. [PMID: 23961438 PMCID: PMC3745667 DOI: 10.4103/2229-5070.113896] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/24/2013] [Indexed: 12/21/2022] Open
Abstract
Blastocystis, an unusual anaerobic, single-celled stramenopile, is a remarkably successful intestinal parasite of a vast array of host species including humans. Fecal Deoxyribonucleic acid (DNA) analysis by nucleic-acid based methods in particular has led to significant advances in Blastocystis diagnostics and research over the past few years enabling accurate identification of carriers and molecular characterization by high discriminatory power. Moreover, Blastocystis comprises a multitude of subtypes (STs) (arguably species) many of which have been identified only recently and molecular epidemiological studies have revealed a significant difference in the distribution of STs across host species and geographical regions. Having a cosmopolitan distribution, the parasite is a common laboratory finding in the stools of individuals with and without intestinal symptoms across the entire globe and while the parasite remains extremely difficult to eradicate and isolate in culture, appropriate molecular tools are now available to resolve important questions such as whether the clinical outcome of colonization is linked to ST and whether Blastocystis is transmitted zoonotically. This review summarizes some of the recent advances in the molecular diagnosis of Blastocystis and gives an introduction to Blastocystis STs, including a recommendation of subtyping methodology based on recent data and method comparisons. A few suggestions for future directions and research areas are given in the light of relevant technological advances and the availability of mitochondrial and nuclear genomes.
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Affiliation(s)
- Christen Rune Stensvold
- Department of Microbiology and Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
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72
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Parija SC, Jeremiah S. Blastocystis: Taxonomy, biology and virulence. Trop Parasitol 2013; 3:17-25. [PMID: 23961437 PMCID: PMC3745665 DOI: 10.4103/2229-5070.113894] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 06/24/2013] [Indexed: 11/20/2022] Open
Abstract
The unicellular protist Blastocystis has long been an unsolved puzzle for taxonomists, microbiologists and clinicians. Over the years, the organism has been bounced on and off the different branches of the tree of life due the possession of unique phenotypic characters intermediary to different organisms. The organism is polymorphic with only few of forms such as vacuolar, granular, amoeboid, and the cyst form being commonly known. However it could exist in other forms much more frequently than the widely known forms which could be missed by the unaware observer. Certain older concepts in the life cycle of Blastocystis although has been proven wrong are still being followed in various textbooks and other trustworthy internet sources. The causal role of Blastocystis in human disease has long been a subject of controversy. It is widely believed that certain subtypes of the organism are virulent. But this is not so as other factors are also involved in the clinical outcome of the infection. In these contexts, this review intends to shed light on the past misconceptions and the recent findings on the taxonomy, biology and the virulence of this organism.
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73
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A rat model to study Blastocytis subtype 1 infections. Parasitol Res 2013; 112:3537-41. [PMID: 23892480 DOI: 10.1007/s00436-013-3536-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 07/05/2013] [Indexed: 10/26/2022]
Abstract
Blastocytis sp. is the most common enteric protozoan in human, but its pathogenesis is still unclear. To study the infectious effects of Blastocytis sp. on tissue damage, we orally challenged the Sprague Dawley (SD) rats with different doses of Blastocytis subtype1 (ST1) and examined the histological changes. We found that there was no difference of disease incidence among the Blastocytis ST1-infected groups challenged with different doses of the protozoan. Histological results showed that the lamina propria was infected by Blastocytis ST1 in the vacuolar form, along with the mucus membrane slough and inflammatory cell infiltration into the lamina propria. Compared to the uninfected group, the histological scores were significantly higher in the infected groups. However, groups infected with various doses of Blastocystis ST1 showed no difference in terms of histological scores. In conclusion, this study indicates that the SD rats can be easily infected with Blastocytis ST1 even with low dose of cysts, and the histopathological effects of the infection in the intestine of the infected rats show individual differences.
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74
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Alfellani MA, Stensvold CR, Vidal-Lapiedra A, Onuoha ESU, Fagbenro-Beyioku AF, Clark CG. Variable geographic distribution of Blastocystis subtypes and its potential implications. Acta Trop 2013; 126:11-8. [PMID: 23290980 DOI: 10.1016/j.actatropica.2012.12.011] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 11/29/2012] [Accepted: 12/20/2012] [Indexed: 01/23/2023]
Abstract
Blastocystis is a common intestinal micro-eukaryote found in both humans and non-human hosts and known to be genetically very diverse. It has been divided into numerous subtypes (STs), nine of which have been identified in humans to date. Surveys of ST prevalence have started to emerge over the past few years but to date no data are available for any African country except Egypt and Tanzania. In this study, we determined the prevalence of Blastocystis STs in populations from Libya, Liberia and Nigeria, as well as expanding the dataset available for the UK. A total of 356 Blastocystis STs were identified in this study, 271 from the UK, 38 from Libya, 25 from Liberia and 22 from Nigeria. SSU rRNA gene sequences revealed the presence of eight of the nine STs known from humans but at varying frequencies between countries. ST1 was the most common ST in Libya and Nigeria whereas ST3 showed the highest frequency in the other two countries, as indeed is the case in most populations around the world. ST4 was absent in Libya and ST2 in Nigeria, while no ST5, ST6, ST8 or ST9 infections were detected in any of the three African populations. The picture emerging from this and other surveys suggests that there is significant variation in ST prevalence between populations. Some of the possible reasons for and implications of this diversity are discussed.
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El Safadi D, Meloni D, Poirier P, Osman M, Cian A, Gaayeb L, Wawrzyniak I, Delbac F, El Alaoui H, Delhaes L, Dei-Cas E, Mallat H, Dabboussi F, Hamze M, Viscogliosi E. Molecular epidemiology of Blastocystis in Lebanon and correlation between subtype 1 and gastrointestinal symptoms. Am J Trop Med Hyg 2013; 88:1203-6. [PMID: 23458955 DOI: 10.4269/ajtmh.12-0777] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Blastocystis is the most common eukaryotic parasite in the intestinal tract of humans. Because of its potential impact in public health, we acquired the first data concerning the prevalence of this parasite and the frequency of the Blastocystis subtypes (STs) in the Lebanese population. In this study, fecal samples from 220 Lebanese symptomatic and asymptomatic patients were collected and a total of 42 patients (19%) were identified as positive for this parasite by direct-light microscopy of smears. Among these, 36 Blastocystis isolates were genotyped using partial small subunit ribosomal RNA gene sequencing. The ST distribution in the present Lebanese population was as follows: ST3 (33.3%), ST2 (33.3%), ST1 (30.6%), and ST4 (2.8%). These data were compared with those available in other Middle Eastern and neighboring countries. Finally, ST1 was significantly more prevalent among symptomatic patients of this Lebanese population.
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Affiliation(s)
- Dima El Safadi
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille Nord de France, EA4547, Lille, France.
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Subtype identification of Blastocystis spp. isolated from patients in a major hospital in northeastern Thailand. Parasitol Res 2012; 112:1781-6. [PMID: 23224731 DOI: 10.1007/s00436-012-3218-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/22/2012] [Indexed: 10/27/2022]
Abstract
The present study is aimed to identify the prevalence of Blastocystis subtypes isolated from patients in a major hospital in northeastern Thailand. A total of 562 stool samples were examined by culture technique, and 56 Blastocystis-positive samples were analyzed further by the combination of restriction fragment length polymorphism (RFLP) followed by polymerase chain reaction with sequence-tagged site primers (PCR-STS). By RFLP profiles, Blastocystis genotypes were categorized into four groups: group A (12, 21.4%), group B (32, 57.1%), group C (10, 17.9%), and group D (2, 3.6%). By PCR-STS, only four subtypes were identified. All 12 (21.4%) isolates in group A were identified as subtype 1. Similarly, all 32 (57.1%) isolates in group B were subtype 3. In group C, 10 (17.9%) samples were all subtype 7, and two samples (3.6%) in group D were both subtype 6. Of 56 Blastocystis-positive patients, 31 (55.4%) were asymptomatic and 22 (39.4%) have gastrointestinal symptoms. No significant association was observed between the Blastocystis subtypes and the clinical features. Among the Blastocystis-positive patients, the most characteristic stool samples were loose (78.6%) and soft (17.9%). In conclusion, the most common Blastocystis spp. in northeastern Thailand was subtype 3 followed by subtype 1. Relatively minor subtypes, subtype 6 and subtype 7 which are considered as avian subtypes, were found for the first time in humans in Thailand.
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Comparison of sequencing (barcode region) and sequence-tagged-site PCR for Blastocystis subtyping. J Clin Microbiol 2012; 51:190-4. [PMID: 23115257 DOI: 10.1128/jcm.02541-12] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Blastocystis is the most common nonfungal microeukaryote of the human intestinal tract and comprises numerous subtypes (STs), nine of which have been found in humans (ST1 to ST9). While efforts continue to explore the relationship between human health status and subtypes, no consensus regarding subtyping methodology exists. It has been speculated that differences detected in subtype distribution in various cohorts may to some extent reflect different approaches. Blastocystis subtypes have been determined primarily in one of two ways: (i) sequencing of small subunit rRNA gene (SSU-rDNA) PCR products and (ii) PCR with subtype-specific sequence-tagged-site (STS) diagnostic primers. Here, STS primers were evaluated against a panel of samples (n = 58) already subtyped by SSU-rDNA sequencing (barcode region), including subtypes for which STS primers are not available, and a small panel of DNAs from four other eukaryotes often present in feces (n = 18). Although the STS primers appeared to be highly specific, their sensitivity was only moderate, and the results indicated that some infections may go undetected when this method is used. False-negative STS results were not linked exclusively to certain subtypes or alleles, and evidence of substantial genetic variation in STS loci was obtained. Since the majority of DNAs included here were extracted from feces, it is possible that STS primers may generally work better with DNAs extracted from Blastocystis cultures. In conclusion, due to its higher applicability and sensitivity, and since sequence information is useful for other forms of research, SSU-rDNA barcoding is recommended as the method of choice for Blastocystis subtyping.
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