51
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52
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Haresh K, Suresh K, Khairul Anus A, Saminathan S. Isolate resistance of Blastocystis hominis to metronidazole. Trop Med Int Health 1999; 4:274-7. [PMID: 10357863 DOI: 10.1046/j.1365-3156.1999.00398.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Isolates of Blastocystis hominis from infected immigrant workers from Indonesia, Bangladesh and infected individuals from Singapore and Malaysia were assessed for growth pattern and degree of resistance to different concentrations of metronidazole. Viability of the cells was assessed using eosin-brillian cresyl blue which stained viable cells green and nonviable cells red. The Bangladeshi and Singaporean isolates were nonviable even at the lowest concentration of 0.01 mg/ml, whereas 40% of the initial inoculum of parasites from the Indonesian isolate at day one were still viable in cultures with 1.0 mg/ml metronidazole. The study shows that isolates of B. hominis of different geographical origin have different levels of resistance to metronidazole. The search for more effective drugs to eliminate th parasite appears inevitable, especially since surviving parasites from metronidazole cultures show greater ability to multiply in subcultures than controls.
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Affiliation(s)
- K Haresh
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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53
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Devera RA, Velásquez VJ, Vásquez MJ. Blastocistosis en pre-escolares de Ciudad Bolívar, Venezuela. CAD SAUDE PUBLICA 1998. [DOI: 10.1590/s0102-311x1998000200016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Para determinar la prevalencia y relevancia clínica de la blastocistosis en una muestra de niños en edad pre-escolar, fueron evaluados 169 alumnos del pre-escolar "Los Coquitos" de Ciudad Bolívar, Venezuela. Las muestras fecales fueron estudiadas mediante la técnica de examen directo y métodos de concentración de Faust y Willis. Se encontraron 72 niños parasitados, de ellos 32 (29,09%) con Blastocystis hominis. Se determinó una prevalencia de infección por este protozoario de 18,93% ± 5,93%. No hubo predilección por el sexo y la edad de los pre-escolares parasitados (ji² = 1.84 DF = 3; p>0.05). Se diagnosticó mayormente como parásito único (53,13%); Giardia lamblia fue el parásito más frecuentemente identificado (39,13%) junto con B. hominis. En el 94,12% de los casos, se observó en un número mayor de 5 células por campo. El 70,58% de los pre-escolares tenía manifestaciones clínicas, sin embargo, la cantidad de Blastocystis presente no fue determinante en su aparición, pero si en la severidad de ellas. Luego del tratamiento, hubo respuesta clínica y parasitológica favorable en el 80% y 90% de los casos, respectivamente. Se concluye que B. hominis es un patógeno de relativa alta frecuencia en el grupo de niños estudiados.
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54
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Bridger S, Evans N, Parker A, Cairns SR. Multiple cerebral venous thromboses in a child with inflammatory bowel disease. J Pediatr Gastroenterol Nutr 1997; 25:533-6. [PMID: 9360209 DOI: 10.1097/00005176-199711000-00009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- S Bridger
- Royal Sussex County Hospital, Brighton, United Kingdom
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55
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Giacometti A, Cirioni O, Balducci M, Drenaggi D, Quarta M, De Federicis M, Ruggeri P, Colapinto D, Ripani G, Scalise G. Epidemiologic features of intestinal parasitic infections in Italian mental institutions. Eur J Epidemiol 1997; 13:825-30. [PMID: 9384273 DOI: 10.1023/a:1007306630301] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To determine the prevalence of intestinal parasitic infections in the residents of four Italian psychiatric institutions, we examined the stool specimens collected in triplicate from 238 residents, enrolled between May 1995 and May 1996. Besides, physician and staff nurses provided data about each resident by standardized questionnaires. Parasites were detected in the fecal samples from 128 patients (53.8%). However, in the stool specimens from 106 residents only non-pathogenic protozoa were found (82.8%). Trichuris trichiura ova, Giardia lamblia cysts and trophozoites, Cryptosporidium parvum oocysts, and Balantidium coli cysts were found in the fecal samples from 22 residents (9.2%). B. hominis was the most prevalent parasite. It was detected in the fecal specimens from 97 residents (40.8%). The so-called nonpathogenic amebae were detected in the fecal specimens from 65 residents, though, at the same time, there was no evidence of Entamoeba histolytica infection. Twelve residents (5.0%) showed intestinal colonization by nonpathogenic flagellates. All the subjects with T. trichiura infection were housed in the facility of Ancona. Parasites were found in fecal samples from all the 11 residents with behavioural aberrations, but only three of those suffering from intestinal pathogen infection associated to diarrhea. Statistical analyses revealed that the presence of pathogenic parasites in fecal specimens was significantly associated with diarrhea, nausea, vomiting, abdominal pain, fever, behavioural aberrations and nonpathogenic protozoa (p < 0.01), but did not demonstrate any other significant associations between these parasites and the other variables, such as pruritus, mucus or blood in the stools and presence of fecal leukocytes. On the other hand, the presence of nonpathogenic protozoa was significantly related to aberrations such as pica, geophagia, phytophagy, coprophagy, coprophilia and pathogenic parasites (p < 0.01). Data analyses revealed that both pathogenic and nonpathogenic parasites were significantly more common in institutionalized patients than in controls. The rare presence of clinical signs and symptoms in colonized patients represents an important public health problem, since the presence of asymptomatic carriers among residents with low hygienic conditions, raises concern of transmission of parasitic infections to professional staff and other residents. Since the eradication of parasitic colonization in residential facilities is hard to reach, an effective prevention is the only measure to deal with this public health problem.
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Affiliation(s)
- A Giacometti
- Institute of Infectious Disease and Public Health, University of Ancona, Italy
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56
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Jelinek T, Peyerl G, Löscher T, von Sonnenburg F, Nothdurft HD. The role of Blastocystis hominis as a possible intestinal pathogen in travellers. J Infect 1997; 35:63-6. [PMID: 9279726 DOI: 10.1016/s0163-4453(97)91025-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The role of Blastocystis hominis as a pathogen for man has been controversially discussed, while travel history has been implicated as a risk factor of infection. Few controlled studies of the association between B. hominis and symptomatic diseases have been performed. Therefore, a case-control study among 795 German tourists returning from tropical countries was conducted. The prevalence of the organism among patients with and without symptoms was assessed. Blastocystis hominis was detected in 69 of 469 (14.7%) patients with diarrhoea and in 21 of 326 (5.7%) controls. However, other organisms causing diarrhoea were detected in 18 of the 69 (26.1%) symptomatic patients with B. hominis. Thus, 51 of 469 (10.8%) symptomatic patients had B. hominis in the absence of other pathogens in their stool, significantly more than in the asymptomatic group (5.2%; P = 0.005). Irrespective of the development of symptoms, the organism was most frequently acquired during journeys to the Indian subcontinent. The results of this study suggest that B. hominis is associated with development of diarrhoea in travellers to tropical destinations and that frequently concurrent infections with other organisms occur.
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Affiliation(s)
- T Jelinek
- Department of Infectious Diseases and Tropical Medicine, University of Munich, München, Germany
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57
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Abstract
Intestinal parasitism is extremely common, with approximately 70% of all people harboring one or more intestinal parasite. Parasitism and diarrhea are both hyperendemic in areas where sanitation is suboptimal. Many clinicians assume that the identification of intestinal parasites in patients with diarrhea implies that the parasites are the cause. This approach is frequently misguided. Some intestinal parasites such as Giardia lamblia and Entamoeba histolytica certainly do cause diarrhea. Others, for example Entamoeba coli and Ascaris lumbricoides, almost certainly do not. In addition, there are a number of other organisms that have been associated with diarrheal illness in some cases, which may or may not be important pathogens. In this article, we will review the role of protozoans as definite and possible causes of diarrhea. In Part II, we review the role of helminths in diarrhea.
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Affiliation(s)
- R Hashmey
- Departments of Medicine, Pathology, and Microbiology and Immunology, Baylor College of Medicine, Houston, Texas
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58
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Yang LQ, Singh M, Yap EH, Ng GC, Xu HX, Sim KY. In vitro response of Blastocystis hominis against traditional Chinese medicine. JOURNAL OF ETHNOPHARMACOLOGY 1996; 55:35-42. [PMID: 9121165 DOI: 10.1016/s0378-8741(96)01471-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This is the first inn vitro study on the activity of 20 kinds of crude extracts of traditional Chinese medicine (TCM) on the intestinal parasite, Blastocystis hominis using the criteria of living cell count (LCC) and living cell rate (LCR). LCC and LCR were applied as observation indicators, the former as a fixed-quantity and the latter as a fixed-quality method. LCR calculated percentage rate of living cells using eosin-brilliant cresyl blue staining which could differentiate between living cells and dying or dead cells. There were five extracts with no inhibitory activity, thirteen with moderate inhibition and two with high inhibition. The crude extracts of Coptis chinensis (CC) and Brucea javanica (BJ) were found to be most active against B. hominis. The active concentration of CC was 100 micrograms/ml. The active concentration of BJ was 500 micrograms/ml. The active concentration of metronidazole (MD) was 10 micrograms/ml and this was taken as an active standard drug for B. hominis.
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Affiliation(s)
- L Q Yang
- Department of Parasitology, Shanghai University of Traditional Chinese Medicine, P.R. China
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59
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Abstract
Blastocystis hominis is a unicellular organism found commonly in the intestinal tract of humans and many other animals. Very little is known of the basic biology of the organism, and controversy surrounds its taxonomy and pathogenicity. There morphological forms (vacuolar, granular, and ameboid) have been recognized, but recent studies have revealed several additional forms (cyst, avacuolar, and multivacuolar). The biochemistry of the organism has not been studied to any extent, and organelles and structures of unknown function and composition are present in the cells. Several life cycles have been proposed but not experimentally validated. The form used for transmission has not been defined. Infections with the organism are worldwide and appear in both immunocompetent and immunodeficient individuals. Symptoms generally attributed to B. hominis infection are nonspecific, and the need for treatment is debated. If treatment appears warranted, metronidazole is suggested as the drug of choice, although failures of this drug in eradicating the organism have been reported. Infection is diagnosed by light microscopic examination of stained smears or wet mounts of fecal material. Most laboratories identify B. hominis by observing the vacuolar form, although morphological studies indicate that other forms, such as the cyst form and multivacuolar form, also should be sought for diagnosis.
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Affiliation(s)
- D J Stenzel
- Analytical Electron Microscopy Facility, Queensland University of Technology, Australia
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60
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Lanuza MD, Carbajal JA, Borrás R. Identification of surface coat carbohydrates in Blastocystis hominis by lectin probes. Int J Parasitol 1996; 26:527-32. [PMID: 8818733 DOI: 10.1016/0020-7519(96)00010-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The carbohydrate residues of the surface coat of 20 axenic cultures of Blastocystis hominis were studied using FITC-labelled lectins (ConA, WGA, DBA, HPA, SBA, PNA, UEAI and LPA). The specific affinity of reactive lectins was determinated by competitive inhibition assay with specific carbohydrates or by enzymatic pre-treatment of cells. All stocks strongly bound ConA and HPA; WGA, UEAI and LPA were partially reactive, and the remaining lectins were nonreactive. Inhibition assays showed abolition (WGA, LPA, UEAI and HPA) or partial reduction (ConA) of lectin affinity, which demonstrated the specificity of binding assay. These results indicate that B. hominis has surface components containing alpha-D-mannose, alpha-D-glucose, N-acetyl-alpha-D-glucosamine, alpha-L-fucose, chitin and sialic acid.
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Affiliation(s)
- M D Lanuza
- Departamento de Microbiología, Facultad de Medicina y Hospital Clínico Universitario, Valencia, Spain
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61
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Albrecht H, Stellbrink HJ, Koperski K, Greten H. Blastocystis hominis in human immunodeficiency virus-related diarrhea. Scand J Gastroenterol 1995; 30:909-14. [PMID: 8578192 DOI: 10.3109/00365529509101600] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND A wide variety of bacterial, viral, and parasitic pathogens can cause severe diarrhea in patients with advanced human immunodeficiency virus (HIV) infection. Conflicting evidence exists as to whether Blastocystis hominis should also be included among the infectious agents capable of causing HIV-related diarrhea. METHODS We determined the prevalence and clinical significance of B. hominis in a cohort of 262 patients with HIV infection, presenting at the infectious diseases department of a tertiary referral university hospital in northern Germany. RESULTS B. hominis was detected in stool samples of 99 patients (38%). The isolation rate varied highly between the different groups. Homosexual men (43%; odds ratio (OR), 2.1; p = 0.01) had a higher detection rate than patients from other risk groups (26%), and patients with acquired immunodeficiency syndrome (46%; OR, 1.8; p = 0.03) were more likely to carry B. hominis than patients in earlier stages of their HIV infection (32%). An association with clinical symptoms was not evident. Presence of B. hominis, however, was frequently associated with the concurrent isolation of other enteric pathogens or apathogenic parasites. CONCLUSIONS The data suggest that the isolation of B. hominis does not justify treatment even in symptomatic, severely immunocompromised patients. Most patients will either have spontaneous resolution of symptoms or successful identification of other infectious or noninfectious etiologies. Therapy should be limited to patients with persistent unexplained symptoms after a thorough evaluation and a complete screening for alternative etiologies, including the use of endoscopic procedures and the careful examination of multiple specimens.
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Affiliation(s)
- H Albrecht
- Medical Outpatient and Inpatient Clinics, Eppendorf University Hospital, Hamburg, Germany
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62
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Overbosch D, Ledeboer M. 'The tropics in our bathroom': chronic diarrhoea after return from the tropics. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1995; 212:43-7. [PMID: 8578232 DOI: 10.3109/00365529509090301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Interest in imported tropical diseases has increased with the rising number of travellers to the tropics. This is especially true in the case of tropical gastroenterologic disorders. The causative organisms of chronic diarrhoea are different from those causing acute diarrhoea. Bacteria are relatively unusual; parasites, e.g. Entamoeba histolytica or Giardia lamblia or an opportunistic parasitic infestation associated with an HIV infection are more likely. Furthermore, non-infectious causes, such as postinfective tropical malabsorption, lactase deficiency or coeliac disease have to be considered. Today, elderly people often undertake a journey to the tropics; in these cases the diarrhoea may be associated not only with an increased susceptibility to tropical bowel infections but also with causes previously present, such as diverticulosis, carcinoma or inflammatory bowel disease. The classification of chronic diarrhoea following a visit to the tropics is essentially the same as that for acute diarrhoea: diarrhoea with and without fever and with and without blood. In addition, malabsorption is an important feature of chronic diarrhoea.
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Affiliation(s)
- D Overbosch
- Dept. of Tropical Medicine, Rode Kruis Ziekenhuis, Gravenhage, The Netherlands
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63
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Nimri L, Batchoun R. Intestinal colonization of symptomatic and asymptomatic schoolchildren with Blastocystis hominis. J Clin Microbiol 1994; 32:2865-6. [PMID: 7852590 PMCID: PMC264178 DOI: 10.1128/jcm.32.11.2865-2866.1994] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A study of single stool specimens was done to determine the prevalence of intestinal parasites among 1,000 primary school children. A questionnaire was completed by each child's parents. Specimens were examined by using wet-mount preparation, formaline-ether concentration, and Sheather's flotation technique. Trichrome and acid-fast stains were done. Blastocystis hominis was observed in 203 (20.3%) of the specimens examined, and 175 specimens contained this organism in the absence of other pathogenic parasites. Older children had fewer B. hominis infections (6 to 7 years old, 50% infection rate; 8 to 9 years, 27.5%; 10 to 12 years, 9.5%). The most common complaints reported by 75 children harboring the parasite were a mild recurrent diarrhea, abdominal pain, nausea, anorexia, and fatigue. Blastocystosis is quite common among schoolchildren. Contaminated drinking water is suspected to be the source of infection.
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Affiliation(s)
- L Nimri
- Department of Biological Sciences, Jordan University of Science and Technology, Irbed
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64
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Abstract
Blastocystis hominis is an enteric protozoan associated with clinical illness. To determine the prevalence of intestinal injury in patients with B. hominis infection, the authors prospectively evaluated 18 patients with B. hominis infection by endoscopy and a test of intestinal permeability. Seventeen patients had gastrointestinal symptoms. Colonic mucosa appeared normal by lower endoscopy in 12 of 13 patients, and was friable slightly in 1. Duodenal mucosa was normal by upper endoscopy in nine patients. Pathologic examination of mucosal biopsy specimens did not demonstrate evidence of mucosal invasion. 51Cr-edetic acid (51Cr-EDTA) was given to the 18 patients with stools positive for B. hominis and to 32 healthy control subjects. Approximately 100 uCi of 51Cr-EDTA was given orally after an overnight fast, and urine was collected for the following 24 hours. Mean 24-hour urinary excretion of 51Cr-EDTA, calculated as a percent of the administered dose, was 1.31% (0.34-2.76%) in patients with B. hominis infection and 1.99% (0.59-3.48%) in the control subjects. The intestinal permeability to 51Cr-EDTA in blastocystis-infected individuals was not increased, but was decreased significantly compared with healthy subjects (p < 0.005). Therefore, in a group of symptomatic patients with B. hominis infection, endoscopy typically did not show evidence of significant intestinal inflammation, and results of intestinal permeability testing with 51Cr-EDTA did not suggest impaired barrier function of the intestinal mucosa. The clinical literature on B. hominis infection and intestinal injury is reviewed.
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Affiliation(s)
- M J Zuckerman
- Department of Medicine, Texas Tech University Health Sciences Center, El Paso 79905
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65
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MacPherson DW, MacQueen WM. Morphological diversity of Blastocystis hominis in sodium acetate-acetic acid-formalin-preserved stool samples stained with iron hematoxylin. J Clin Microbiol 1994; 32:267-8. [PMID: 7510311 PMCID: PMC263015 DOI: 10.1128/jcm.32.1.267-268.1994] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The objective of this investigation was to study the morphological characteristics of Blastocystis hominis in sodium acetate-acetic acid-Formalin-preserved stool samples. Routinely processed samples were examined for morphological detail, including size, shape, nuclear detail, and central body characteristics. Morphological findings revealing the importance of recognizing B. hominis in the diagnostic laboratory are described.
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Affiliation(s)
- D W MacPherson
- Infectious Diseases and Tropical Medicine Clinic, Chedoke-McMaster Hospitals (McMaster Division), Hamilton, Ontario, Canada
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66
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Nimri LF. Evidence of an epidemic of Blastocystis hominis infections in preschool children in northern Jordan. J Clin Microbiol 1993; 31:2706-8. [PMID: 8253970 PMCID: PMC265984 DOI: 10.1128/jcm.31.10.2706-2708.1993] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Blastocystis hominis is now gaining acceptance as an agent of human intestinal disease. A case-control study of the cause of gastroenteritis in children less than 6 years old was conducted. A total of 500 stool specimens were examined by wet mount preparation, formalin-ether concentration, Sheather's sugar flotation technique, and permanent stains when necessary. B. hominis was found in 63 (25%) of 250 stool specimens of the cases examined; 38 (15%) of these specimens contained this parasite alone. The appearance of severe symptoms was associated with increased numbers of the parasite in the diarrheic specimens (more than five parasites per field at a magnification of x 400). The most common symptoms were abdominal pain, recurrent diarrhea, cramps, anorexia, and fatigue. Contaminated water was suspected to be the major source of infection, since several cases were associated with Giardia infection. These findings support the concept of B. hominis pathogenicity in children with gastroenteritis.
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Affiliation(s)
- L F Nimri
- Department of Biological Sciences, Faculty of Science, Jordan University of Science and Technology, Irbed
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67
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O'Gorman MA, Orenstein SR, Proujansky R, Wadowsky RM, Putnam PE, Kocoshis SA. Prevalence and characteristics of Blastocystis hominis infection in children. Clin Pediatr (Phila) 1993; 32:91-6. [PMID: 8432086 DOI: 10.1177/000992289303200206] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Blastocystis hominis, a protozoan whose pathogenicity has been questioned, is sometimes found in the human gastrointestinal tract. We sought to determine the prevalence of Blastocystis in stool and to characterize clinical features of infection with Blastocystis in children. Forty-six (3%) of 1,736 patients undergoing fecal microscopy at Children's Hospital of Pittsburgh between January 1, 1985, and December 31, 1988, harbored Blastocystis. Of these 46 children, 75% had exposure to well water or had been in developing countries. Thirty-nine of the 46 (85%) experienced gastrointestinal symptoms, such as abdominal pain, diarrhea, vomiting, and weight loss. Blastocystis was the only parasite found in 35 of those 39 symptomatic children. Symptoms resolved within one month in 90% of patients receiving antiparasitic pharmacotherapy, but in only 58% (P < .04) of those receiving no therapy. We conclude that children infected with Blastocystis often experience gastrointestinal symptoms and that treatment increases the rate of symptomatic improvement. We speculate that Blastocystis is a human pathogen.
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Affiliation(s)
- M A O'Gorman
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, Pennsylvania 15213
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68
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Boreham PF, Stenzel DJ. Blastocystis in humans and animals: morphology, biology, and epizootiology. ADVANCES IN PARASITOLOGY 1993; 32:1-70. [PMID: 8237614 DOI: 10.1016/s0065-308x(08)60206-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- P F Boreham
- Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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69
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Abstract
Travelers returning from third-world countries may become infected with a variety of intestinal parasites. Although protozoan infections are more frequently seen, intestinal worms are also encountered. If considered in the differential diagnosis, these infections usually are readily diagnosed and treated.
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Affiliation(s)
- M Wittner
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York
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70
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Martín-Sánchez AM, Canut-Blasco A, Rodríguez-Hernández J, Montes-Martínez I, García-Rodríguez JA. Epidemiology and clinical significance of Blastocystis hominis in different population groups in Salamanca (Spain). Eur J Epidemiol 1992; 8:553-9. [PMID: 1397225 DOI: 10.1007/bf00146376] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A prospective study was carried out to investigate the epidemiology and clinical significance of Blastocystis hominis in the following groups of the population of the city of Salamanca (Spain): in children attending 11 day care centres and 7 primary schools, two fecal samples were obtained from each child, and in 1231 patients attending the Clinical Hospital. A B. hominis incidence of 5.3-10.3% was found in the day care centres and an incidence rate of 13.4-19.4% was found in the primary schools. All the cases were observed in asymptomatic children. The incidence of B. hominis was greater in children older than 3 years in the day care centres and in the 10-14 year-old group in the primary schools. A heavier parasitization was observed in the boys than in the girls and in the students of schools in areas of low socio-economic level. B. hominis was identified in 40 patients attending the Clinical Hospital (3.25% of all those studied). The maximum peak of incidence was found in subjects with ages between 10 and 14 years. A follow up study was performed on 18 patients parasitized exclusively by B. hominis; 7 of these were considered to have acute gastroenteritis and one chronic gastroenteritis associated with the protozoan. No statistically significant association was observed between the number of B. hominis cells and the presence of diarrhoea. Our results show that despite the high number of asymptomatic carriers of B. hominis in the juvenile population, this protozoan may be, on other occasions, responsible for gastrointestinal symptoms.
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71
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Keenan TW, Huang CM, Zierdt CH. Comparative analysis of lipid composition in axenic strains of Blastocystis hominis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1992; 102:611-5. [PMID: 1499298 DOI: 10.1016/0305-0491(92)90055-v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. Six axenic strains of Blastocystis hominis varied in content of lipids from 12 to 43 pg total lipid/cell. With all strains, phospholipid content was about 39% of total lipids. 2. Neutral lipid fractions of B. hominis were resolved into nine constituents, of which seven were identified tentatively. Sterol esters, principally esters of cholesterol, were the major neutral lipid constituent, accounting for 49-63% of the neutral lipids, and at least 30% of the total lipids. 3. Polar lipids were resolved into eleven constituents, of which nine were identified tentatively. Phosphatidylcholine was the major polar lipid constituent of all strains, accounting for 53-63% of the polar lipids, and about 22% of the total lipids.
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Affiliation(s)
- T W Keenan
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg 24061
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72
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Kukoschke KG, Müller HE. Varying incidence of Blastocystis hominis in cultures from faeces of patients with diarrhoea and from healthy persons. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1992; 277:112-8. [PMID: 1520961 DOI: 10.1016/s0934-8840(11)80879-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A study was performed on the frequency of Blastocystis hominis in the faeces from 100 patients suffering from diarrhoea and from 100 healthy persons. Surprisingly, an increased detection rate was observed in samples from healthy persons after anaerobic cultivation. This increased frequency is obviously not dependent on the kind of serum used as a culture supplement and raises the question whether the protozoa morphologically described as B. hominis represent a homogenous species. When rabbit and horse sera were used instead of human serum for cultivation, in both groups the share of positive cultures increased and more large forms of B. hominis cells were observed. Biological implications are being discussed.
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Affiliation(s)
- K G Kukoschke
- Staatliches Medizinaluntersuchungsamt, Braunschweig, Germany
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73
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Hing MC, Goldschmidt C, Mathijs JM, Cunningham AL, Cooper DA. Chronic colitis associated with human immunodeficiency virus infection. Med J Aust 1992; 156:683-7. [PMID: 1352372 DOI: 10.5694/j.1326-5377.1992.tb121507.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE A clinical and pathological description of chronic colitis associated with human immunodeficiency virus (HIV) infection. DESIGN A retrospective case review. SETTING Tertiary referral institution and specialist gastroenterology practice. PATIENTS A series of six patients with human immunodeficiency virus infection and chronic colitis observed for up to four years. RESULTS The six patients had chronic diarrhoea for longer than six months, rectal bleeding, abdominal pain and stool leukocytosis. The mucosal pattern on colonoscopy showed diffuse proctocolitis, consisting of contact bleeding, superficial ulcerations, exudates, and/or loss of vascular pattern. Colonic biopsies showed a persisting diffuse colitis characterised principally by a mixed inflammatory cell infiltrate (mononuclear cells and neutrophils) and essentially preserved crypt architecture after six to 39 months of histological follow-up. The histopathology over this time frame was not typical of ulcerative colitis or Crohn's disease, nor of the conventionally described forms of infective colitis. HIV nucleic acid was identified by insitu hybridisation in colonic biopsies from four patients. In two of three patients tested, the presence of HIV DNA was confirmed by Southern blot analysis. No other microbial agent could be demonstrated as the cause of diarrhoea. At presentation all patients had CD4+ lymphocyte counts greater than 265 x 10(6)/L and none had the acquired immunodeficiency syndrome. Four patients have gone into remission, the other two patients were not in remission at four and a half to five years after onset. CONCLUSION We suggest that chronic colitis may represent a new entity related to infection of the colon with human immunodeficiency virus.
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Affiliation(s)
- M C Hing
- Bruce Hall Department of Gastroenterology, St Vincent's Hospital, Darlinghurst, NSW
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Ashford RW, Atkinson EA. Epidemiology of Blastocystis hominis infection in Papua New Guinea: age-prevalence and associations with other parasites. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1992; 86:129-36. [PMID: 1417203 DOI: 10.1080/00034983.1992.11812642] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A community-based study of Blastocystis and other intestinal parasites in the Asaro Valley, Papua New Guinea showed an extraordinary high prevalence and variety of protozoan infections. Apart from infants, nearly everybody had at least one infection, and the mean number of infections per person was around 2.7. The graph of age-specific prevalence for Blastocystis is similar in shape to those for Entamoeba coli and Endolimax nana, indicating probable similarity in transmission patterns and host response. There was no evidence for pathogenicity of Blastocystis at the community level. Three methods are compared for the measurement of association between infections. Two show strong associations, but these are considered to be the result of parallel age-prevalence curves and environmental factors at the village level. When age- and village-matched pairs were considered, only a weak positive association with E. nana was detectable.
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75
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Jeddy TA, Farrington GH. Blastocystis Hominis Complicating Ulcerative Colitis. Med Chir Trans 1991; 84:623. [PMID: 1744851 PMCID: PMC1295566 DOI: 10.1177/014107689108401021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- T A Jeddy
- Kingston Hospital, Kingston-Upon-Thames
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77
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Lakhanpal S, Cohen SB, Fleischmann RM. Reactive arthritis from Blastocystis hominis. ARTHRITIS AND RHEUMATISM 1991; 34:251-3. [PMID: 1994931 DOI: 10.1002/art.1780340227] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Abstract
The history of B. hominis is unique. Few infectious agents have provoked the many misconceptions that plague this enigmatic parasitic ameba. Conflicting descriptions of its nature and pathogenesis have continued throughout the 20th century. As seen by the greatly expanded number of reports in recent years, B. hominis is now a major subject of study, particularly for evidence of disease causation. Physicians are treating patients with intestinal disease caused by B. hominis. Many mild cases resolve in about 3 days without treatment, but others are acute and chronic disease is common. As with E. histolytica, the carrier state is often seen without symptoms. Treatment is usually with metronidazole, but emetine (for refractory infections), trimethoprim-sulfamethoxazole, and pentamidine are also effective. In fecal samples, this complex protozoan appears in a variety of cell forms which makes microscopic diagnosis difficult. As yet, no specific fluorescent-antibody test is available for diagnosis. A culture method to demonstrate the more easily recognized CB form is available, but probably not feasible for most diagnostic laboratories. The common cell forms are the CB form, the granular (mitochondria) form, and the ameba form. The unexpected size range of these forms in clinical material, from yeast size (ca. 7 microns) to giant cells of 20 to 40 microns, makes diagnosis difficult Pseudopodia may be demonstrated by the ameba form in heated microscope stage culture chambers. The anaerobic B. hominis has no cyst form. Its mitochondria are uniquely anaerobic and have no cytochrome protein or oxidative mitochondrial enzymes. Because of its many cell forms and anaerobic mitochondria, B. hominis is an organism of great interest for morphologic and biochemical study. Reproduction is asexual, usually by binary fission. Shizogony occurs in cultured cells. The CB appears to be an organelle whose specific purpose is for reproduction by shizogony. From 2 to 30 progeny are derived from schizogony. The ameba form reproduces by plasmotomy; it has no CB. The pathology of B. hominis infections has been studied in gnotobiotic guinea pigs in which inflammation of the intestinal mucosa and invasion of the superficial layers were seen. Only limited studies of human pathology are available. Those who have studied mucosal histopathology report inflammation and cellular changes that resolve after treatment. More study in this area is strongly indicated (32, 44, 57, 62, 67, 75). Ultrastructural details of B. hominis major forms, except for the schizont, are complete. The organism has no cell wall. The concentric CB takes up as much as 95% of the cell. The major organelles, which include multiple nuclei, Golgi apparatus, mitochondria, endoplasmic reticulum, fat, and other inclusions, are confined in two or four opposed pods in a thin band of peripheral cytoplasm between the spherical entire plasma membrane and the CB membrane. The pods buldge the CB membrane inward. There is evidence of a bacteroid endosymbiont. Education about B. hominis is needed. Entry of recent findings into new textbooks is imperative for its understanding among medical practitioners. Laboratory workers need to be aware of it for many reasons. The College of American Pathologists includes B. hominis in its proficiency testing samples and requires that it be reported from clinical samples.
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Affiliation(s)
- C H Zierdt
- Microbiology Service, Clinical Pathology Department, National Institutes of Health, Bethesda, Maryland 20892, USA
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79
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Abstract
Infectious diarrhea is the largest single cause of morbidity and mortality in the world. Bacteria, viruses, and protozoan parasites are the most common causative agents. Treatment in most cases of bacterial and viral diseases consists of correcting fluid loss and electrolyte imbalance by oral or parenteral rehydration. Antimicrobial therapy is reserved for very ill patients only. With the exception of Cryptosporidium, for which no effective agent is yet available, all protozoan infections are treatable with metronidazole.
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Affiliation(s)
- S M Qadri
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital, Research Centre, Riyach, Saudi Arabia
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84
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Kukoschke KG, Necker A, Müller HE. Detection of Blastocystis hominis by direct microscopy and culture. Eur J Clin Microbiol Infect Dis 1990; 9:305-7. [PMID: 2351150 DOI: 10.1007/bf01968071] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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85
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Libonore M, Bicocchi R, Sighinolfi L, Ghinelli F. Blastocystosis in drug-addicts with HIV-1 infection. Eur J Epidemiol 1990; 6:108-9. [PMID: 2344871 DOI: 10.1007/bf00155563] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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86
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Garavelli PL, Scaglione L, Bicocchi R, Libanore M. Blastocystosis: a new disease in the acquired immunodeficiency syndrome? Int J STD AIDS 1990; 1:134-5. [PMID: 2092790 DOI: 10.1177/095646249000100214] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The protozoon Blastocystis hominis may cause episodes of diarrhoea with abdominal pain, tenesmus, fever and eosinophilia. We have observed 5 cases of blastocystosis in male subjects with symptomatic HIV infection. All patients had a complete response to metronidazole. This report confirms that Blastocystis hominis may be responsible for HIV-related diarrhoea.
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Affiliation(s)
- P L Garavelli
- Department of Infectious Diseases, General Hospital, Alessandria, Italy
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87
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Doyle PW, Helgason MM, Mathias RG, Proctor EM. Epidemiology and pathogenicity of Blastocystis hominis. J Clin Microbiol 1990; 28:116-21. [PMID: 2298869 PMCID: PMC269548 DOI: 10.1128/jcm.28.1.116-121.1990] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A prospective study was performed on a large outpatient population to evaluate the epidemiology and pathogenicity of Blastocystis hominis. Patients with stool specimens positive for B. hominis and negative for other bacterial and parasitic pathogens were sent a questionnaire and were requested to submit a follow-up specimen for ova-and-parasite examination. B. hominis was identified in 530 of 16,545 specimens (3.2%). There was a spectrum of clinical-pathological presentations in the 143 patients evaluated. An asymptomatic carrier state was seen in 19 patients. Fifteen patients had an illness consistent with acute self-limited B. hominis gastroenteritis, and 21 patients had chronic gastroenteritis associated with B. hominis. In the epidemiological evaluation of 130 patients, the most common symptoms were watery diarrhea, abdominal pain, and gas. We did not find a statistically significant association between the number of organisms present and the disease state. In summary, our results are consistent with a role for B. hominis in acute and chronic gastroenteritis; however, further detailed studies are necessary to determine whether that role is one of association or causation.
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Affiliation(s)
- P W Doyle
- Metro-McNair Clinical Laboratories, Vancouver, British Columbia, Canada
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89
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Babb RR, Wagener S. Blastocystis hominis--a potential intestinal pathogen. West J Med 1989; 151:518-9. [PMID: 2603418 PMCID: PMC1026784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The parasite Blastocystis hominis has been found in 10% to 18% of stool specimens submitted to microbiology laboratories. Controversy exists as to whether this organism can cause illness in humans. We have reviewed the records of 65 symptomatic patients with B hominis in their stool. We conclude that B hominis is a potential pathogen that may or may not require drug therapy depending on the overall clinical circumstances, the severity of symptoms, and the presence of other pathogenic organisms.
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Abstract
A total of 19,252 stool specimens from 12,136 patients were examined by direct microscopy and the ethyl acetate-Formalin concentration method during the last 2 years. All liquid specimens and those in which parasite identification was difficult or equivocal were also examined in trichrome-stained preparations. A total of 3,070 intestinal parasites were seen in 2,889 patients. Blastocystis hominis was found in fecal material from 647 patients (17.5%). A total of 132 cases (25.6%) were observed to be in association with other enteric pathogens. B. hominis in large numbers was present as the only parasite or with other commensals in 515 specimens from patients (79.6%). Of these patients, 239 (46.4%) had symptoms, the most common being abdominal pain (87.9%), constipation (32.2%), diarrhea (23.4%), alternating diarrhea and constipation (14.5%), vomiting (12.5%), and fatigue (10.5%). Forty-three (18%) of the patients were treated with metronidazole (0.5 to 1.0 g/day) because of recurrent symptoms and the presence of large numbers of B. hominis cells in repeated stool specimens. After 7 to 10 days of treatment, all patients became asymptomatic with negative stools on follow-up examinations for B. hominis.
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Affiliation(s)
- S M Qadri
- Department of Pathology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Johnson AM, Thanou A, Boreham PF, Baverstock PR. Blastocystis hominis: phylogenetic affinities determined by rRNA sequence comparison. Exp Parasitol 1989; 68:283-8. [PMID: 2649390 DOI: 10.1016/0014-4894(89)90110-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In 1912 Blastocystis hominis was identified as a new species and classified as a yeast (Brumpt 1912). In the early 1920s several groups confirmed its classification as a yeast, specifically a member of the genus Schizosaccharomyces (discussed by Zierdt et al. 1967). Apart from an occasional case report, the classification of B. hominis and its role as a harmless intestinal yeast was not questioned for another 50 years. Then, Zierdt (1967) suggested that it should be classified in the phylum Protozoa, subphylum Sporozoa, and that it should be considered as a potential pathogen. The likely role of B. hominis as a human pathogen has recently become more firmly established (Garcia et al. 1984; Sheehan et al. 1986) and its classification has been changed. Although the classification of B. hominis as a protozoon was assumed widely, classification as a sporozoon was not accepted, and the most recent definitive classification of the Protozoa did not even list B. hominis (Lee et al. 1985). Then, based essentially on a review of the known characteristics of the organism, it was recently reclassified into the subphylum Sarcodina (Zierdt 1988). Clearly, the phylogeny of this emerging human pathogen needs definitive analysis (Mehlhorn 1988).
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Affiliation(s)
- A M Johnson
- Department of Clinical Microbiology, Flinders University of South Australia School of Medicine, Bedford Park
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Yoshikawa H, Yamada M, Yoshida Y. Freeze-fracture study of Blastocystis hominis. THE JOURNAL OF PROTOZOOLOGY 1988; 35:522-8. [PMID: 3199336 DOI: 10.1111/j.1550-7408.1988.tb04143.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ultrastructure of Blastocystis hominis was investigated by the freeze-fracture method. Freeze-fracture replicas of the membranes of B. hominis and its organelles were studied with special regard to the density and distribution of the intramembranous particles (IMP's). On all membrane replicas, the concentration of IMP's on the protoplasmic face (P face) invariably was greater than on the exoplasmic face (E face). On the P face, IMP's were heterogeneously distributed in dense aggregates, alternating with particle-free, smooth surface areas. Occasionally, small depressions and protrusions were observed in these areas. On the membrane of the central vacuole, invaginations into the vacuole were frequently observed within the smooth surface regions. Since most of the granules in the central vacuoles had no IMP's, it seems likely that the intervacuolar granules were formed from these invaginations of the vacuole membrane. The width of the intermembrane space between the inner and outer membranes of the nuclear envelope was uneven, with regions of relative narrowness interspersed with regions of expansion. Nuclear pores were localized within the narrow portions of this space. A nucleus, apparently in the process of dividing, was observed enclosed within an intact outer membrane. Division of the outer membrane would then result in the formation of two discrete nuclei.
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Affiliation(s)
- H Yoshikawa
- Department of Medical Zoology, Kyoto Prefectural University of Medicine, Japan
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