Displaying publications 1 - 20 of 77 in total

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  1. Wild hosts and microscopic worlds: Investigating the morphology and surface ultrastructure of Blastocystis sp. in avian and non-human primate species
    Sanggari A, Attah AO, Yahaya ZS, Farah Haziqah MT
    Trop Biomed, 2023 Dec 01;40(4):392-399.
    PMID: 38308825 DOI: 10.47665/tb.40.4.003
    Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate's pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite's adaptations and potential implications for host health.
    Matched MeSH terms: Blastocystis*
  2. Blastocystis sp. reduces the efficacy of 5-fluorouracil as a colorectal cancer chemotherapeutic treatment
    Kumarasamy V, Kuppusamy UR, Jayalakshmi P, Govind SK
    Exp Parasitol, 2023 Aug;251:108564.
    PMID: 37308003 DOI: 10.1016/j.exppara.2023.108564
    Blastocystis is an enteric protozoan parasite with extensive genetic variation and unclear pathogenicity. It is commonly associated with gastrointestinal symptoms such as nausea, diarrhea, vomiting and abdominal pain in immunocompromised individuals. In this study, we explored the in vitro and in vivo effects of Blastocystis on the activity of a commonly used CRC chemotherapeutic agent, 5-FU. The cellular and molecular effects of solubilized antigen of Blastocystis in the presence of 5-FU were investigated using HCT116, human CRC cell line and CCD 18-Co, normal human colon fibroblast cells. For the in vivo study, 30 male Wistar rats were divided into six groups, as follows; Control Group: oral administration of 0.3 ml Jones' medium, Group A: rats injected with azoxymethane (AOM), Group A-30FU: Rats injected with AOM and administered 30 mg/kg 5-FU, Group B-A-30FU: rats inoculated with Blastocystis cysts, injected with AOM and administered 30 mg/kg 5-FU, Group A-60FU: rats injected with AOM and administered 60 mg/kg 5-FU and Group B-A-60FU: rats inoculated with Blastocystis cysts, injected with AOM and administered 60 mg/kg 5-FU. The in vitro study revealed that the inhibitory potency of 5-FU at 8 μM and 10 μM was reduced from 57.7% to 31.6% (p 
    Matched MeSH terms: Blastocystis*
  3. The role and influence of bacteria on the growth of Blastocystis sp. subtype 3
    Kaur CP, Yong CC, Rajamanikam A, Samudi C, Kumar S, Bhassu S, et al.
    Parasitol Res, 2023 Jul;122(7):1463-1474.
    PMID: 37162590 DOI: 10.1007/s00436-023-07842-2
    Blastocystis sp. is an enteric protistan parasite that affects individuals worldwide with gastrointestinal symptoms such as abdominal discomfort, diarrhea, and flatulence. However, its pathogenicity is controversial due to its presence among asymptomatic individuals. Blastocystis sp. subtype 3 (ST3) is the most prevalent subtype among humans that have been associated with irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis, and colorectal cancer. Axenization of the parasite has been shown to impede its growth thus revealing the importance of accompanying bacteria in ensuring Blastocystis sp. survival. This study aims to identify the influence of accompanying bacteria on the growth of Blastocystis sp. ST3. Blastocystis sp. cultures were treated with Meropenem, Vancomycin, and Amoxicillin-Clavulanic acid (Augmentin). Bacteria-containing supernatant of antibiotic-treated and control cultures were isolated and identified through 16 s rRNA sequencing. Morphological changes of antibiotic-treated Blastocystis sp. ST3 were also observed. The cultures treated with meropenem and augmentin exhibited opposing effects with reduced growth of isolates from symptomatic patients and a significant increase in asymptomatic isolates. Whereas, vancomycin-treated cultures had no difference in the growth of Blastocystis sp. ST3 isolates from symptomatic and asymptomatic patients. Isolates from symptomatic and asymtomatic patients had 6 and 2 distinct bacterial species identified with Proteus mirabilis as the common bacteria among both types of isolates. Morphologically, Blastocystis sp. ST3 cultures exposed to meropenem and augmentin demonstrated an increase in pre-cystic forms. These findings demonstrate the effects of accompanying bacteria on the growth of Blastocystis sp. ST3 that could translate into clinical manifestations observed among Blastocystis sp.-infected patients.
    Matched MeSH terms: Blastocystis*
  4. Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review
    Attah AO, Sanggari A, Li LI, Nik Him NAII, Ismail AH, Meor Termizi FH
    Parasitol Res, 2023 Jan;122(1):1-10.
    PMID: 36434314 DOI: 10.1007/s00436-022-07731-0
    There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.
    Matched MeSH terms: Blastocystis*
  5. Fulltext Comparison of apoptotic responses in Blastocystis sp. upon treatment with Tongkat Ali and Metronidazole
    Girish S, Kumar S, Aminudin N, Hashim NM
    Sci Rep, 2021 04 09;11(1):7833.
    PMID: 33837230 DOI: 10.1038/s41598-021-81418-x
    Blastocystis sp. infection, although many remain asymptomatic, there is growing data in recent studies that suggests it is a frequent cause of gastrointestinal symptoms in children and adults. This proposes that treatment against this infection is necessary however metronidazole (MTZ), which is the current choice of treatment, has expressed non-uniformity in its efficacy in combating this infection which has led to the study of alternative treatment. In our previous study, it was established that Tongkat Ali fractions exhibited promising anti-protozoal properties which leads to the current aim of the study, to further narrow down the purification process in order to identify the specific active compound promoting the anti-protozoal effect through HPLC analysis. Based on the data analysis and in-vitro susceptibility assay, the collected Tongkat Ali fraction that demonstrated anti-blastocystis property was shown to contain eurycomanone. Previous studies have suggested that there is a mechanism in Blastocystis sp. that regulates the apoptotic process to produce higher number of viable cells when treated. In reference to this, our current study also aims to investigate the apoptotic response of Tongkat Ali extract and eurycomanone across different subtype groups with comparison to MTZ. Based on our investigation, both Tongkat Ali extract and eurycomanone induced the high apoptotic rate however exhibited a reduction in viable cell count (p 
    Matched MeSH terms: Blastocystis Infections/parasitology*; Blastocystis/drug effects*; Blastocystis/isolation & purification; Blastocystis/metabolism
  6. Fulltext Current status of Blastocystis sp. in animals from Southeast Asia: a review
    Rauff-Adedotun AA, Mohd Zain SN, Farah Haziqah MT
    Parasitol Res, 2020 Nov;119(11):3559-3570.
    PMID: 32951145 DOI: 10.1007/s00436-020-06828-8
    Blastocystis is the most frequently observed eukaryotic gastrointestinal symbiont in humans and animals. Its low host specificity and zoonotic potential suggest that animals might serve as possible reservoirs for transmission. The prevalence and subtype distributions of Blastocystis sp. in animal populations in Southeast Asia, a hotspot for zoonotic diseases, are reviewed. Recommendations for future research aimed at understanding the zoonotic role of Blastocystis are also included. Seven countries have, so far, reported Blastocystis infection in various animals, such as livestock, poultry, companion animals, and non-human primates. Pigs were the most studied animals, and there were records of 100% prevalence in pigs, cattle, and ostriches. Using polymerase chain reaction (PCR)-based approaches, twelve Blastocystis sp. subtypes (STs), namely ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST8, ST9, ST10, ST12, and ST14 have been recognised infecting animals of Southeast Asia. ST1 and ST5 were the most frequently identified, and Malaysia observed the most diverse distribution of subtypes. Further investigations on Blastocystis sp. in various animal hosts, using adequate sample sizes and uniform detection methods, are essential for a better understanding of the distribution of this organism. Detailed genome studies, especially on STs shared by humans and animals, are also recommended.
    Matched MeSH terms: Blastocystis Infections/epidemiology; Blastocystis Infections/veterinary*; Blastocystis/genetics; Blastocystis/isolation & purification*
  7. Prevalence and subtypes of Blastocystis among migrant workers from different working sectors in Peninsular Malaysia
    Sahimin N, Meor Termizi FH, Rajamanikam A, Mohd Nazri NA, Govind SK, Mohd Zain SN
    Parasitol Res, 2020 Oct;119(10):3555-3558.
    PMID: 32875397 DOI: 10.1007/s00436-020-06865-3
    Blastocystis sp. is a common enteric parasite of humans and animals associated with inadequate sanitation and poor personal hygiene. Over the years, the Malaysian thriving economy has been facilitated largely by migrant workers from developing countries, and there is concern that diseases endemic to their countries may be imported. Therefore, this study aimed to determine the current status of Blastocystis infection as well as subtypes (STs) from fecal samples among migrant workers in Selangor and Kuala Lumpur, Malaysia. Overall, almost a third of the study cohort (30.9%; n = 68/220) screened were infected with Blastocystis sp. predominantly with ST3 (54.5%; n = 12), followed by ST1 (36.4%; n = 8) and ST2 (9.1%; n = 2). Infection levels was almost similar among the different sectors; manufacturing (32.8%), domestic service (32.3%), and food service (27.3%) with common symptoms for infection included stomach and abdominal pain or discomfort and diarrhea (48.5%; n = 33). None of the socio-demographic risk factors evaluated were significant. Therefore, this study warrants continuous monitoring as well as understanding the impact of transmission among the migrant community with the local population especially those involved in food service sector.
    Matched MeSH terms: Blastocystis Infections/diagnosis; Blastocystis Infections/epidemiology*; Blastocystis Infections/parasitology*; Blastocystis/classification*; Blastocystis/genetics; Blastocystis/isolation & purification*
  8. Epitope variances demonstrated by Blastocystis sp. ST3 symptomatic and asymptomatic isolates
    Sheela DS, Chandramathi S, Suresh K
    Trop Biomed, 2020 Mar 01;37(1):210-217.
    PMID: 33612732
    Blastocystis sp. is an enteric protozoan parasite of humans and many animals. Blastocystis sp. subtype 3 (ST3) proves to be the highest frequency case in most populations around the world and it is further distinguished into symptomatic and asymptomatic isolates based on the clinical symptoms exhibited by infected individuals. Phenotypic and genotypic studies implicate the distinctiveness of this parasite which may describe its pathogenesis. However, the antigenic distinctiveness which describes the antibody mediated cell lysis of this parasite has not been explored. This study was aimed to identify the cross-reactivity and cytotoxicity effect between three isolates of symptomatic and asymptomatic Blastocystis sp. ST3 respectively. Antigen specificity and diversity of this parasite was performed by coculturing sera (10-fold dilution) obtained from mice immunised with Blastocystis sp. symptomatic and asymptomatic antigens and the respective Blastocystis sp. ST3 live cells through complement dependant cell cytotoxicity (CDC) assay. The results obtained has shown that, the sera (at 10-fold diluted concentration) from symptomatic and asymptomatic solubilised antigen immunised mice were able to specifically lyse the respective live parasites with an average percentage of 82% and 86% respectively. There were almost 50% crossreactivity observed between the three isolates of Blastocystis sp. ST3 from symptomatic and asymptomatic group proving high antigen diversity or rather low antigen specificity within the same group. However, there was only 17% cross-reactivity observed between the mice sera and parasitic cells of different groups (symptomatic vs asymptomatic isolates) suggesting high specificity between these two groups. We, for the first time have proven that through CDC analysis there were epitopes dissimilarities between Blastocystis sp. ST3 symptomatic and asymptomatic isolates which may allow the parasite to set up diverse immune modulations such as imbalanced Th1/Th2 responses in an infected host.
    Matched MeSH terms: Blastocystis Infections/immunology; Blastocystis Infections/parasitology*; Blastocystis/immunology*
  9. Prevalence and subtype distribution of Blastocystis sp. in cattle from Pahang, Malaysia
    Kamaruddin SK, Mat Yusof A, Mohammad M
    Trop Biomed, 2020 Mar 01;37(1):127-141.
    PMID: 33612724
    Blastocystis sp. is a common enteric protozoan parasite found in humans and various type of animal worldwide. Recently, genotypic distribution of Blastocystis sp. was revealed in insects, rodents, avian and mammals, which exposed its potential of transmiting the infections to human. However, very little information on current level of Blastocystis sp. infection were reported in cattle from Malaysia. Herein, a total of 120 stool samples of cattles were collected. While the potential risk of infection such as age, gender, body score, diarrheic condition of the cattle were noted, the management of the farms was also recorded. All stool sample were cultured, but 80 samples were selected for PCR sequencing analysis. The cultivation and microscopic examination revealed only 25% of the cattle (30/120) were infected with Blastocystis sp.. But, 43.8% of the cattle (35/80) were found positive upon PCR sequencing. The study also found that age, body score condition, diarrheic condition and certain farm were associated with the infection (p<0.05). Six subtypes (STs) that were discovered during the study were ST10 (21.3%;17/35), ST5 (8.8%;7/35), ST3 (7.5%;6/35), ST1 (2.5%;2/35), ST4 (2.5%;2/35) and ST14 (1.3%;1/35). Thus, moderate infections of Blastocystis sp. and variants in the genotypic distributions of the cattle suggest its potential for zoonotic transmission. Therefore, this findings could be helpful for further understanding the parasite, which assist studies of its pathogenicity.
    Matched MeSH terms: Blastocystis Infections/epidemiology; Blastocystis Infections/parasitology; Blastocystis Infections/veterinary*; Blastocystis/classification; Blastocystis/isolation & purification*
  10. A case report of Blastocystis infection and Steven Johnson's syndrome
    Singh A, Priyadarshi K, Raj T, Banerjee T
    Trop Biomed, 2019 Dec 01;36(4):987-992.
    PMID: 33597468
    Blastocystis species (spp.) is an emerging pathogen. There are several unsolved issues linked to this parasite ranging from its nomenclature, commensal status, standardization of laboratory diagnostic methods, genotypes and treatment. Recently, there has been an increase in reports of Blastocystis spp. from symptomatic cases which provide enough evidence of its pathogenic potential. A range of signs and symptoms, from gastro-intestinal to cutaneous manifestations have been attributed to Blastocystis infection. Few reports have established an association between intestinal infection with Blastocystis spp. and skin manifestations in form of urticaria, palmoplantar pruritus and allergy with complete resolution of cutaneous lesions with eradication of the parasite. In this report, we describe a case of Steven Johnson's syndrome (SJS) in a 6 years old girl along with infection with Blastocystis spp. marked by diarrhea and abdominal pain. Stool examination revealed the presence of all forms of the parasite with subsequent decrease in parasite burden and diarrhea over a period of time. Interestingly, the clearance of Blastocystis spp. from stool was followed by recovery from skin lesions and other symptoms. In this case, the course of SJS was clearly associated with Blastocystis infection. Though skin manifestation with Blastocystis infection has been previously reported, this is the first report of its association with SJS. This report indicates newer insights of the parasite that are less well studied.
    Matched MeSH terms: Blastocystis Infections/diagnosis*
  11. Fulltext A Review of Quercus infectoria (Olivier) Galls as a Resource for Anti-parasitic Agents: In Vitro and In Vivo Studies
    Zin NNINM, Rahimi WNAWM, Bakar NA
    Malays J Med Sci, 2019 Nov;26(6):19-34.
    PMID: 31908584 MyJurnal DOI: 10.21315/mjms2019.26.6.3
    Parasitic diseases represent one of the causes for significant global economic, environmental and public health impacts. The efficacy of currently available anti-parasitic drugs has been threatened by the emergence of single drug- or multidrug-resistant parasite populations, vector threats and high cost of drug development. Therefore, the discovery of more potent anti-parasitic drugs coming from medicinal plants such as Quercus infectoria is seen as a major approach to tackle the problem. A systematic review was conducted to assess the efficacy of Q. infectoria in treating parasitic diseases both in vitro and in vivo due to the lack of such reviews on the anti-parasitic activities of this plant. This review consisted of intensive searches from three databases including PubMed, Science Direct and Scopus. Articles were selected throughout the years, limited to English language and fully documented. A total of 454 potential articles were identified, but only four articles were accepted to be evaluated based on inclusion and exclusion criteria. Although there were insufficient pieces of evidence to account for the efficacy of Q. infectoria against the parasites, this plant appears to have anti-leishmanial, anti-blastocystis and anti-amoebic activities. More studies in vitro and in vivo are warranted to further validate the anti-parasitic efficacy of Q. infectoria.
    Matched MeSH terms: Blastocystis
  12. Establishing a protocol for water sample processing for the detection of Blastocystis sp
    Lee IL, Tan TC, Govind SK
    Exp Parasitol, 2019 Mar;198:105-110.
    PMID: 30695704 DOI: 10.1016/j.exppara.2019.01.007
    This study was aimed at establishing a protocol for water sample processing for the detection of Blastocystis sp. using distilled water spiked with Blastocystis sp. cysts. The study established a protocol involving eight technical aspects, namely, storage temperature, storage duration, minimum water sample volume, optimum relative centrifugal force, centrifugation duration, minimum number of cyst for inoculation in Jones' medium and turn-around-time for the detection of vacuolar forms of Blastocystis sp. Results showed a minimum of 1.0 L water sample should be collected and processed on the same day. Otherwise, it should be stored at 4 °C and processed within 3 days. Water sample should be centrifuged at 1400×g for 10 min. For the isolation of Blastocystis sp. cysts, parasite pellet could be layered on top of Ficoll-Paque™ PLUS, centrifuged at 1400×g for 20 min and washed twice using 0.9% saline with centrifugation at 1400×g for 10 min. A minimum of 1 × 105 cysts could then be inoculated in Jones' medium supplement with 10% horse serum, incubated at 37 °C and examined for any presence of vacuolar forms of Blastocystis sp. after 3 days of inoculation. A protocol for water sample processing for the detection of Blastocystis sp. has successfully been established. The protocol was validated using 106 various water samples. This protocol will be very useful in determining the extent of Blastocystis sp. contamination in water sources in order to identify the seriousness of contamination.
    Matched MeSH terms: Blastocystis
  13. Fulltext Resistance towards metronidazole in Blastocystis sp.: A pathogenic consequence
    Rajamanikam A, Hooi HS, Kudva M, Samudi C, Kumar S
    PLoS One, 2019;14(2):e0212542.
    PMID: 30794628 DOI: 10.1371/journal.pone.0212542
    Blastocsytis sp. is a protozoan parasite that has been linked to common gastrointestinal illnesses. Metronidazole, the first line therapy, was reported to show frequent inefficacy. Previously, Blastocystis sp. isolated from different population showed varying metronidazole resistance. However, the effect of metronidazole treatment on pathogenic potentials of Blastocystis sp. isolated from different populations, which is known to have different gut environment, is unclear. This study investigates the in vitro effect of metronidazole on the pathogenic potentials of Blastocystis sp. isolated from urban and orang asli individuals. Blastocystis sp. ST 3 isolated from symptomatic and asymptomatic individuals were treated with a range of metronidazole concentration. The parasites' growth characteristics, apoptotic rate, specific protease activity and the ability to proliferate cancer cells were analyzed upon treatment with 0.001 mg/l metronidazole. The study demonstrates that Blastocystis sp. isolates showed increase in the parasite numbers especially the amoebic forms (only in urban isolates) after treating with metronidazole at the concentration of 0.001 mg/ml. High number of cells in post-treated isolates coincided with increase of apoptosis. There was a significant increase in cysteine protease of Blastocystis sp. isolates upon treatment despite the initial predominance of serine protease in asymptomatic isolates. Metronidazole resistant Blastocystis sp. also showed significant increase in cancer cell proliferation. Resistance to metronidazole did not show significant different influence on the pathogenicity between Blastocystis sp. isolated from urban and orang asli individual. However, an increase in parasite numbers, higher amoebic forms, cysteine protease and ability to proliferate cancer cells implicates a pathogenic role. The study provides evidence for the first time, the effect of metronidazole towards enhancing pathogenic potentials in Blastocystis sp. when isolated from different gut environment. This necessitates the need for reassessment of metronidazole treatment modalities.
    Matched MeSH terms: Blastocystis Infections/drug therapy*; Blastocystis Infections/pathology
  14. Fulltext Effect of Blastocystis sp. in dengue patients-Increase in the treatment cost and exacerbation of symptoms
    Thergarajan G, Kumar S, Bhassu S, Omar SFBS, Rampal S
    PLoS One, 2019;14(3):e0211034.
    PMID: 30893309 DOI: 10.1371/journal.pone.0211034
    Increasing incidences of dengue have become a global health threat with major clinical manifestation including high fever and gastrointestinal symptoms. These symptoms were also expressed among Blastocystis sp. infected individuals, a parasite commonly seen in human stools. This parasite has been previously reported to replicate faster upon exposure to high temperature. The present study is a hospitalized-based cross-sectional study involved the collection of faecal sample from dengue patients. Stool examination was done by in vitro cultivation to isolate Blastocystis sp. Growth pattern of all the positive isolates were analyzed to identify the multiplication rate of Blastocystis sp. isolated from dengue patients. Distribution of Blastocystis sp. among dengue patients was 23.6%. Dengue patients who were positive for Blastocystis sp. infection denoted a significantly higher fever rate reaching 38.73°C (p<0.05) compared to the non-Blastocystis sp. infected patients (38.44°C). It was also found that Blastocystis sp. infected patients complained of frequenting the toilet more than five times a day (p<0.05) compared to those who were non-Blastocystis sp. infected. At the same time, the duration of hospitalization was significantly longer (p<0.05) for Blastocystis sp. infected dengue patients compared to the non-Blastocystis sp. infected patients. Besides, Blastocystis sp. isolated from dengue patients (in vivo thermal stress) showed a higher growth rate compared to the non-dengue isolated which was exposed to high temperature (in vitro thermal stress). Our findings suggest that presence of Blastocystis sp. during dengue infection could trigger the increase of temperature which could be due to highly elevated pro inflammatory cytokines by both parasitic and virus infection. This could justify why the temperature in Blastocystis sp. infected dengue patients is higher compared to the non-Blastocystis sp. infected patients. Higher temperature could have triggered a greater parasite multiplication rate that contributed to the aggravation of the gastrointestinal symptoms.
    Matched MeSH terms: Blastocystis Infections/metabolism*; Blastocystis Infections/parasitology; Blastocystis/isolation & purification; Blastocystis/metabolism
  15. Subtype distribution of Blastocystis isolated from humans and associated animals in an indigenous community with poor hygiene in Peninsular Malaysia
    Mohammad NA, Al-Mekhlafi HM, Anuar TS
    Trop Biomed, 2018 Dec 01;35(4):849-860.
    PMID: 33601835
    Blastocystis is one of the most common parasites inhabiting the intestinal tract of human and animals. Currently, human Blastocystis isolates are classified into nine subtypes (STs) based on the phylogeny of their small subunit ribosomal RNA (SSU rRNA) gene. Although its pathogenicity remains controversial, the possibility of zoonotic transmission was recognized since eight of the nine STs (except for ST9) have been reported in both humans and animals. A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis isolated from humans and associated animals in an indigenous community with poor hygiene in Malaysia, where the risk of parasitic infection is high. A total of 275 stool samples were collected, subjected to DNA extraction and amplified by PCR assay. The Blastocystis-positive amplicons were then purified and sequenced. Phylogenetic tree of positive isolates, reference strains and outgroup were constructed using maximum likelihood method based on Hasegawa-KishinoYano+G+I model. The prevalence of Blastocystis infection among humans and domestic animals by PCR assay were 18.5% (45/243) and 6.3% (2/32), respectively. Through molecular phylogeny, 47 isolates were separated into five clusters containing isolates from both hosts. Among human isolates, ST3 (53.3%) was the predominant subtype, followed by ST1 (31.1%) and ST2 (15.6%). Chicken and cattle had lower proportions of ST6 (50%) and ST10 (50%), that were barely seen in humans. The distinct distributions of the most important STs among the host animals as well as humans examined demonstrate that there is various host-specific subtypes in the lifecycle of Blastocystis.
    Matched MeSH terms: Blastocystis Infections; Blastocystis
  16. Exacerbated symptoms in Blastocystis sp.-infected patients treated with metronidazole: two case studies
    Rajamanikam A, Kumar S, Samudi C, Kudva M
    Parasitol Res, 2018 Aug;117(8):2585-2590.
    PMID: 29872961 DOI: 10.1007/s00436-018-5948-x
    Blastocystis sp. is a gastrointestinal (GI) protozoan parasite reported to cause non-specific GI symptoms including diarrhea, flatulence, abdominal pain, and nausea. Complete eradication of Blastocystis sp. is rather challenging even with the drug of choice, i.e., metronidazole. Here, we report on two Blastocystis sp.-infected individuals, who presented increased parasite load and exacerbated symptoms upon treatment with the usual recommended dosage and regime of metronidazole. The two studies uniquely demonstrate for the first time a cyst count as high as fivefold more than the original cyst count before treatment and show an exacerbation of GI symptoms despite treatment. The study provides additional support in recognizing metronidazole resistance in Blastocystis sp. and its consequences towards the pathogenicity of the parasite.
    Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/physiopathology*; Blastocystis/drug effects; Blastocystis/pathogenicity
  17. In vitro and in vivo thermal stress induces proliferation of Blastocystis sp
    Thergarajan G, Govind SK, Bhassu S
    Parasitol Res, 2018 Jan;117(1):177-187.
    PMID: 29188368 DOI: 10.1007/s00436-017-5688-3
    Blastocystis sp. is known to be the most commonly found intestinal protozoan parasite in human fecal surveys and has been incriminated to cause diarrhea and abdominal bloating. Binary fission has been widely accepted as the plausible mode of reproduction for this parasite. The present study demonstrates that subjecting the parasites in vitro to higher temperature shows the proliferation of parasite numbers in cultures. Transmission electron microscopy was used to compare the morphology of Blastocystis sp. subtype 3 isolated from a dengue patient having high fever (in vivo thermal stress) and Blastocystis sp. 3 maintained at 41 °C (in vitro thermal stress) and 37 °C (control). Fluorescence stains like acridine orange (AO) and 4',6'-diamino-2-phenylindole (DAPI) were used to demonstrate the viability and nuclear content of the parasite for both the in vitro and in vivo thermal stress groups of parasites. Blastocystis sp. at 37 °C was found to be mostly vacuolar whereas the in vitro thermal stressed isolates at 41 °C were granular with electron dense material seen to protect the granules within the central body. Parasites of the in vivo thermal stressed group showed similar ultrastructure as the in vitro ones. AO and DAPI staining provided evidence that these granules are viable which develop into progenies of Blastocystis sp. These granular forms were then observed to rupture and release progenies from the mother cells whilst the peripheral cytoplasmic walls were seen to degrade. Upon exposure to high temperature both in vitro and in vivo, Blastocystis sp. in cultures show higher number of granular forms seen to be protected by the electron dense material within the central body possibly acting as a protective mechanism. This is possibly to ensure the ability to survive for the granules to be developed as viable progenies for release into the host system.
    Matched MeSH terms: Blastocystis Infections/parasitology; Blastocystis/isolation & purification; Blastocystis/physiology*; Blastocystis/ultrastructure
  18. Blastocystis sp., Parasite Associated with Gastrointestinal Disorders: An Overview of its Pathogenesis, Immune Modulation and Therapeutic Strategies
    Kumarasamy V, Anbazhagan D, Subramaniyan V, Vellasamy S
    Curr Pharm Des, 2018;24(27):3172-3175.
    PMID: 30084327 DOI: 10.2174/1381612824666180807101536
    Blastocystis sp. is a unicellular parasitic microorganism commonly found in the gastrointestinal tracts of humans and animals. It causes symptomatic or asymptomatic infection and its route of transmission is via fecal-oral. High prevalence of Blastocystis infection in developing countries is usually due to poor hygiene practices, exposure to animals infected with the parasite and intake of contaminated water or food. Blastocystis infected individuals often suffer from diarrhea, abdominal pain, nausea, and stomach bloating. Even though pathogenicity of Blastocystis is unclear, it is commonly associated with irritable bowel syndrome. In this review, we have analysed the evidence that shows the association between this microorganism and gastrointestinal disorders. There have been a number of studies which showed that the pathogenicity of Blastocystis is related to its different STs. The pathogenicity is speculated to be due to cysteine proteases formation which stimulates mucosal cells to release interleukin-8 which has been associated with extreme dehydration and gut inflammation. In vitro studies on human colonic epithelial cells revealed that incubation of Blastocystis modulated the host immune response by stimulating the formation of pro-inflammatory cytokines and granulocyte macrophage colonystimulating factor. Metronidazole is found to be the first-line drug of choice. Another treatment option is the combination therapy with trimethoprim/sulfamethoxazole.
    Matched MeSH terms: Blastocystis/drug effects*; Blastocystis/immunology; Blastocystis/parasitology
  19. Fulltext Molecular epidemiology of blastocystosis in Malaysia: does seasonal variation play an important role in determining the distribution and risk factors of Blastocystis subtype infections in the Aboriginal community?
    Noradilah SA, Moktar N, Anuar TS, Lee IL, Salleh FM, Manap SNAA, et al.
    Parasit Vectors, 2017 Jul 31;10(1):360.
    PMID: 28760145 DOI: 10.1186/s13071-017-2294-2
    BACKGROUND: Alternating wet and dry seasons may play an important role in the acquisition and distribution of Blastocystis subtype infection in the tropics. This cross-sectional study was therefore conducted to provide the prevalence of Blastocystis and to determine the potential risk factors associated with each subtype during the wet and dry seasons in the Aboriginal community, Pahang, Malaysia.

    METHODS: A total of 473 faecal samples were collected: 256 (54.1%) and 217 (45.9%) samples were obtained during the wet (October-November 2014) and the dry season (June 2015), respectively. All fresh faecal samples were subjected to molecular analysis for subtype and allele identification.

    RESULTS: Of the 473 samples, 42.6% and 37.8% were positive for Blastocystis ST1, ST2, ST3 and ST4 during wet and dry seasons, respectively. Prevalence of Blastocystis ST1 was significantly higher during the wet season compared to the dry season (Z = 2.146, P 

    Matched MeSH terms: Blastocystis Infections/ethnology*; Blastocystis Infections/parasitology; Blastocystis Infections/transmission; Blastocystis/genetics*
  20. Fulltext Exacerbation of colon carcinogenesis by Blastocystis sp
    Kumarasamy V, Kuppusamy UR, Jayalakshmi P, Samudi C, Ragavan ND, Kumar S
    PLoS One, 2017;12(8):e0183097.
    PMID: 28859095 DOI: 10.1371/journal.pone.0183097
    Colorectal cancer (CRC) is one the most commonly diagnosed cancers worldwide and the number is increasing every year. Despite advances in screening programs, CRC remains as the second leading cause of cancer deaths in the United States. Oxidative stress plays an important role in the molecular mechanisms of colorectal cancer (CRC) and has been shown to be associated with Blastocystis sp., a common intestinal microorganism. In the present study, we aimed to identify a role for Blastocystis sp. in exacerbating carcinogenesis using in vivo rat model. Methylene blue staining was used to identify colonic aberrant crypt foci (ACF) and adenomas formation in infected rats whilst elevation of oxidative stress biomarker levels in the urine and serum samples were evaluated using biochemical assays. Histological changes of the intestinal mucosa were observed and a significant number of ACF was found in Blastocystis sp. infected AOM-rats compared to the AOM-controls. High levels of urinary oxidative indices including advanced oxidative protein products (AOPP) and hydrogen peroxide were observed in Blastocystis sp. infected AOM-rats compared to the uninfected AOM-rats. Our study provides evidence that Blastocystis sp. has a significant role in enhancing AOM-induced carcinogenesis by resulting damage to the intestinal epithelium and promoting oxidative damage in Blastocystis sp. infected rats.
    Matched MeSH terms: Blastocystis/pathogenicity
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