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Dib I, Fakih M, Noureddine H, Salami A, Alphonse V, Livet A, Bousserrhine N. Assessment of domestic water quality of households and schools in Nabatieh, Lebanon, and development of a new spectrophotometric method for the detection of Entamoeba spp. In tap water. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122945. [PMID: 37984472 DOI: 10.1016/j.envpol.2023.122945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 11/22/2023]
Abstract
Polluted resources of potable water are daily used for different purposes in Lebanon. The optical microscopy is the traditional method used for the detection of Entamoeba spp. in water despite its weak sensitivity. We aimed to characterize domestic water at Nabatieh district, South Lebanon, and to develop a simple method for Entamoeba spp. detection. A total of 70 water samples were collected from houses and schools and analyzed for physical (pH, total dissolved solids and temperature), chemical (nitrate, phosphate and sulfate) and bacterial (total and fecal coliforms) parameters. The contamination by Entamoeba spp. was examined using microscopy, then a spectrophotometric wavelength scan was recorded for 50 samples in order to determine the common peak between positive samples. High phosphate levels were detected in all the samples, with important bacterial and parasitological contaminations. The spectrophotometric analyses showed a peak repetition at the wavelength of 696 nm in the spectrum of the majority of positive samples. The number of cysts was significantly correlated to optical densities at 696 nm (R = 0.9087; p-value<0.0001). The regression analysis showed that the OD696 could statistically predict the concentration (F (1,48) = 267.02, p-value <0.001). In conclusion, potable water parameters at Nabatieh district did not meet the national and international guidelines of safe drinking water, and the detection of Entamoeba spp. cysts in potable water can be performed using a rapid spectrophotometric analysis, by the determination of the optical density at 696 nm and the application of a specific equation.
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Affiliation(s)
- Israa Dib
- Laboratoire Eau, Environnement, Systèmes Urbains (LEESU), University Paris-Est Créteil, Créteil Cedex, 94010, France; Environmental Health Research Laboratory, Faculty of Sciences V, Lebanese University, Nabatieh, Lebanon.
| | - Mohamad Fakih
- Environmental Health Research Laboratory, Faculty of Sciences V, Lebanese University, Nabatieh, Lebanon.
| | - Hiba Noureddine
- Environmental Health Research Laboratory, Faculty of Sciences V, Lebanese University, Nabatieh, Lebanon.
| | - Ali Salami
- Department of Mathematics, Faculty of Sciences, Lebanese University, Nabatieh, Lebanon.
| | - Vanessa Alphonse
- Laboratoire Eau, Environnement, Systèmes Urbains (LEESU), University Paris-Est Créteil, Créteil Cedex, 94010, France.
| | - Alexandre Livet
- Laboratoire Eau, Environnement, Systèmes Urbains (LEESU), University Paris-Est Créteil, Créteil Cedex, 94010, France.
| | - Noureddine Bousserrhine
- Laboratoire Eau, Environnement, Systèmes Urbains (LEESU), University Paris-Est Créteil, Créteil Cedex, 94010, France.
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Morán P, Serrano-Vázquez A, Rojas-Velázquez L, González E, Pérez-Juárez H, Hernández EG, Padilla MDLA, Zaragoza ME, Portillo-Bobadilla T, Ramiro M, Ximénez C. Amoebiasis: Advances in Diagnosis, Treatment, Immunology Features and the Interaction with the Intestinal Ecosystem. Int J Mol Sci 2023; 24:11755. [PMID: 37511519 PMCID: PMC10380210 DOI: 10.3390/ijms241411755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/12/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
This review of human amoebiasis is based on the most current knowledge of pathogenesis, diagnosis, treatment, and Entamoeba/microbiota interactions. The most relevant findings during this last decade about the Entamoeba parasite and the disease are related to the possibility of culturing trophozoites of different isolates from infected individuals that allowed the characterization of the multiple pathogenic mechanisms of the parasite and the understanding of the host-parasite relationship in the human. Second, the considerable advances in molecular biology and genetics help us to analyze the genome of Entamoeba, their genetic diversity, and the association of specific genotypes with the different amoebic forms of human amoebiasis. Based on this knowledge, culture and/or molecular diagnostic strategies are now available to determine the Entamoeba species and genotype responsible for invasive intestinal or extraintestinal amoebiasis cases. Likewise, the extensive knowledge of the immune response in amoebiasis with the appearance of new technologies made it possible to design diagnostic tools now available worldwide. Finally, the understanding of the interaction between the Entamoeba species and the intestinal microbiota aids the understanding of the ecology of this parasite in the human environment. These relevant findings will be discussed in this review.
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Affiliation(s)
- Patricia Morán
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Angélica Serrano-Vázquez
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Liliana Rojas-Velázquez
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Enrique González
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Horacio Pérez-Juárez
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Eric G Hernández
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Maria de Los Angeles Padilla
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Martha E Zaragoza
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
| | - Tobías Portillo-Bobadilla
- Unidad de Bioinformática, Bioestadística y Biología Computacional, Red de Apoyo a la Investigación, Coordinación de la Investigación Científica, Universidad Nacional Autónoma de México (UNAM)-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico
| | - Manuel Ramiro
- División de Estudios de Posgrado, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico
| | - Cecilia Ximénez
- Laboratorio de Inmunología, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 06726, Mexico
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3
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Adao DEV, Li AOC, Dy AES, Rivera WL. Development of a salivary IgA detection method for accurate diagnosis of amebiasis. J Parasit Dis 2022; 46:714-721. [PMID: 36091277 PMCID: PMC9458784 DOI: 10.1007/s12639-022-01490-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 04/09/2022] [Indexed: 10/18/2022] Open
Abstract
An amebiasis detection method was developed based on identifying anti-Entamoeba histolytica IgA in the saliva of infected individuals. The enzyme-linked immunosorbent assay (ELISA)-based detection method was tested along with microscopy and polymerase chain reaction (PCR) on saliva and stool samples from 110 asymptomatic individuals visiting the Manila Health Department - Public Health Laboratory of the City of Manila, Philippines. A receiver operating curve (ROC) was constructed to compare the ELISA results with PCR results. E. histolytica infection was detected in 18 of the 110 individuals. The developed method had an accuracy of 90%, sensitivity of 88.89%, specificity of 90.22%, positive predictive value of 64%, and negative predictive value of 97.65% if a 1:2 dilution of crude saliva sample in phosphate-buffered saline (PBS) was used for diagnosis when compared to PCR. The area under the curve (AUC) of the ROC was 0.9436 if a 1:2 dilution of a crude saliva sample was used. The developed assay presents an easy and accurate method of detecting amebiasis in infected individuals using saliva samples instead of stool or blood samples and has potential applications in both diagnosis and epidemiological studies.
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Affiliation(s)
- Davin Edric V. Adao
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
| | - Angeline Odelia C. Li
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
| | - Alexander Edward S. Dy
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
| | - Windell L. Rivera
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, 1101 Quezon City, Philippines
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4
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Abstract
Among the Entamoeba species that infect humans, Entamoeba histolytica causes diseases, Entamoeba dispar is a harmless commensal, Entamoeba moshkovskii seems to be a pathogen, and the pathogenicity of Entamoeba bangladeshi remains to be investigated. Species-specific detection needed for treatment decisions and for understanding the epidemiology and pathogenicity of these amebae. Antigen-based detection methods are needed for E dispar, E moshkovskii, and E bangladeshi; and molecular diagnostic test capable of detecting E histolytica, E dispar, E moshkovskii, and E bangladeshi simultaneously in clinical samples. Next-generation sequencing of DNA from stool is needed to identify novel species of Entamoeba.
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Affiliation(s)
- Ibne Karim M Ali
- Division of Foodborne Waterborne and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road Northeast, Mailstop D-66, Atlanta, GA 30329, USA.
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5
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Queza MIP, Rivera WL. Diagnosis and molecular characterization of Trichomonas vaginalis in sex workers in the Philippines. Pathog Glob Health 2013; 107:136-40. [PMID: 23683368 DOI: 10.1179/2047773213y.0000000085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Trichomonas vaginalis is a pathogenic protozoon which causes the sexually transmitted infection, trichomoniasis. The absence or non-specificity of symptoms often leads to misdiagnosis of the infection. In this study, 969 samples consisting of vaginal swabs and urine were collected and screened from social hygiene clinics across the Philippines. Of the 969 samples, 216 were used for the comparative analysis of diagnostic tools such as wet mount microscopy, culture, and PCR utilizing universal trichomonad primers, TFR1/2 and species-specific primers, TVK3/7 and TV1/2. PCR demonstrated higher sensitivity of 100% compared to 77% of the wet mount. PCR primer set TVK3/7 and culture had the same and the best expected average performance [receiver-operating characteristic (ROC): 0·98]. Prevalence of infection in the sample population was 6·8%.
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Affiliation(s)
- Macario Ireneo P Queza
- Institute of Biology, College of Science, University of the Philippines, Quezon City, Philippines
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Rivera WL, Ong VA. Development of loop-mediated isothermal amplification for rapid detection of Entamoeba histolytica. ASIAN PAC J TROP MED 2013; 6:457-61. [PMID: 23711706 PMCID: PMC7128414 DOI: 10.1016/s1995-7645(13)60074-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 04/15/2013] [Accepted: 05/15/2013] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To develop a loop-mediated isothermal amplification (LAMP) assay for the detection of Entamoeba histolytica E. histolytica, the causative agent of amebiasis. METHODS The LAMP primer set was designed from E. histolytica hemolysin gene HLY6. Genomic DNA of E. histolytica trophozoites strain HK9 was used to optimize the LAMP mixture and conditions. Amplification of DNA in the LAMP mixture was monitored through visual inspection for turbidity of the LAMP mix as well as addition of fluorescent dye. RESULTS Positive LAMP reactions turned turbid while negative ones remained clear. Upon addition of a fluorescent dye, all positive reactions turned green while the negative control remained orange under ambient light. After electrophoresis in 1.5% agarose gels, a ladder of multiple bands of different sizes can be observed in positive samples while no bands were detected in the negative control. The sensitivity of the assay was found to be 5 parasites per reaction which corresponds to approximately 15.8 ng/μ L DNA. The specificity of the assay was verified by the absence of amplified products when DNA from other gastrointestinal parasites such as the morphologically similar but non-pathogenic species, Entamoeba dispar 39, and other diarrhea-causing organisms such as Blastocystis hominis and Escherichia coli were used. CONCLUSIONS The LAMP assay we have developed enables the detection of E. histolytica with rapidity and ease, therefore rendering it is suitable for laboratory and field diagnosis of amebiasis.
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Affiliation(s)
- Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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7
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Yang B, Chen Y, Wu L, Xu L, Tachibana H, Cheng X. Seroprevalence of Entamoeba histolytica infection in China. Am J Trop Med Hyg 2012; 87:97-103. [PMID: 22764298 PMCID: PMC3391064 DOI: 10.4269/ajtmh.2012.11-0626] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 04/14/2012] [Indexed: 12/23/2022] Open
Abstract
The seroprevalence of Entamoeba histolytica infection in the residents of seven provinces in China was examined by using an enzyme-linked immunosorbent assay with a crude antigen and a recombinant surface antigen, C-Igl, of the parasites. A total of 1,312 serum samples were investigated. The positivity rates for these two antigens were 11.05% and 6.25%, respectively. There was no significant difference in the seropositivity to E. histolytica between men and women. We used a logistic regression model and maximal-likelihood methods to estimate the prevalence of E. histolytica infection from sequential serologic data. Seropositivity in Sichuan, Guizhou, and Sinkiang Provinces was higher than that in Beijing, Shanghai, and Qinghai Provinces. The present study provides an overview of seropositivity to E. histolytica infection in seven provinces in China and use the logistic regression model estimation method to achieve a more accurate measure of amebiasis prevalence.
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Affiliation(s)
- Bin Yang
- Department of Microbiology and Parasitology, Shanghai Medical College, Fudan University, Shanghai, China.
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8
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Berrilli F, Prisco C, Friedrich KG, Di Cerbo P, Di Cave D, De Liberato C. Giardia duodenalis assemblages and Entamoeba species infecting non-human primates in an Italian zoological garden: zoonotic potential and management traits. Parasit Vectors 2011; 4:199. [PMID: 21988762 PMCID: PMC3214166 DOI: 10.1186/1756-3305-4-199] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 10/12/2011] [Indexed: 12/03/2022] Open
Abstract
Background Giardia duodenalis and Entamoeba spp. are among the most common intestinal human protozoan parasites worldwide and they are frequently reported in captive non-human primates (NHP). From a public health point of view, infected animals in zoos constitute a risk for animal caretakers and visitors. In this study we carried out the molecular identification of G. duodenalis and Entamoeba spp. from nine species of primates housed in the zoological garden of Rome, to better ascertain their occurrence and zoonotic potential. Results G. duodenalis was found only in Lemur catta (47.0%). Entamoeba spp. were detected in all species studied, with the exception of Eulemur macaco and Varecia rubra. The number of positive pools ranged from 5.9% in L. catta to 81.2% in Mandrillus sphinx; in Pan troglodytes the observed prevalence was 53.6%. A mixed Entamoeba-Giardia infection was recorded only in one sample of L. catta. All G. duodenalis isolates belonged to the zoonotic assemblage B, sub assemblage BIV. Three Entamoeba species were identified: E. hartmanni, E. coli and E. dispar. Conclusions Our results highlight the importance of regularly testing animals kept in zoos for the diagnosis of zoonotic parasites, in order to evaluate their pathogenic role in the housed animals and the zoonotic risk linked to their presence. A quick detection of the arrival of pathogens into the enclosures could also be a prerequisite to limit their spread into the structure via the introduction of specific control strategies. The need for molecular identification of some parasite species/genotype in order to better define the zoonotic risk is also highlighted.
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Affiliation(s)
- Federica Berrilli
- Dipartimento di Sanità Pubblica e Biologia Cellulare, Università di Roma TorVergata, Rome, Italy
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9
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Abstract
Museum and archival collections of parasites are available throughout the world but, although they represent a huge diversity of species and forms, they tend to be used solely for reference to morphology, if at all. As biochemical techniques begin to overcome the problems associated with ancient, degraded and formalin-fixed tissues, the value of such collections increases. Molecular data are now available for rare, elusive and extinct species, as well as those densely sampled for epidemiological, biogeographical or clinical collections. Here, Elisabeth Herniou, Auriol Pearce and Tim Littlewood describe some of the advances and pitfalls associated with retrieving DNA from formalin-fixed helminth material and suggest just some of the new ways that parasitologists can tap into these resources.
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Affiliation(s)
- E A Herniou
- The Natural History Museum, Department of Zoology, Cromwell Road, London, UK SW7 5BD
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10
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Entamoeba histolytica and E. dispar infections in captive macaques (Macaca fascicularis) in the Philippines. Primates 2009; 51:69-74. [PMID: 19862480 DOI: 10.1007/s10329-009-0174-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
Entamoeba histolytica is a protozoan parasite that infects man and animals. This parasite has a global distribution and the disease it causes is usually characterized by diarrhea. In order to detect the parasite, it is necessary to differentiate it from Entamoeba dispar. E. dispar appears morphologically similar to E. histolytica but does not cause disease and tissue invasion. This study reports on the prevalence of E. histolytica and E. dispar among captive macaques in a primate facility in the Philippines. PCR was used to correctly identify both Entamoeba species. Indirect fluorescent antibody test (IFAT) was also performed to determine the seroprevalence of amebiasis in the captive macaques. Based on PCR targeting of the peroxiredoxin gene, of the 96 stool samples collected, 23 (24%) contained E. histolytica while 32 (33%) contained E. dispar. IFAT revealed 26 (27%) serum samples positive for antibodies against E. histolytica. Sequence analysis of the 18S rRNA gene showed that the 23 E. histolytica isolates were identical to human E. histolytica isolates deposited in the GenBank and not Entamoeba nuttalli as found in macaques in other recent reports. The Philippines is a major exporter of monkeys for biomedical research purposes, so screening animals before transporting them to other locations lessens the risk of spreading zoonoses to a wider area. This is the first report of the molecular detection of E. histolytica and E. dispar among macaques in the Philippines. This study complements the limited information available on the animal hosts of E. histolytica in the Philippines.
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11
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Molecular characterization of Trichomonas vaginalis isolates from the Philippines. Parasitol Res 2009; 106:105-10. [DOI: 10.1007/s00436-009-1635-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 09/08/2009] [Indexed: 10/20/2022]
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12
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Rivera WL, Adao DEV. 18S ribosomal DNA genotypes of Acanthamoeba species isolated from contact lens cases in the Philippines. Parasitol Res 2009; 105:1119-24. [PMID: 19562379 DOI: 10.1007/s00436-009-1531-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
Abstract
This study was carried out to document the genotypes of Acanthamoeba present in contact lens cases from 50 randomly selected contact lens wearers living in Quezon City, Metro Manila, Philippines. Acanthamoeba species were isolated from eight (16%) in 50 contact lens cases examined. We analyzed partial 18S ribosomal DNA (Rns) sequences of the eight isolates and found that the sequence differences were sufficient to distinguish the genotypes. After the isolates were genotyped, using the Basic Local Alignment Search Tool program, their phylogenetic positions relative to known Acanthamoeba isolates were determined. The model-based (GTR+Gamma+Iota) neighbor-joining, maximum likelihood, and Bayesian inference analyses, as well as the non-model-based maximum parsimony analysis were used. Results showed that of the eight isolates, six were Rns genotype T5 while two were Rns genotype T4. This present study indicates that genotype T5 is also a common contaminant in contact lens storage cases.
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Affiliation(s)
- Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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13
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Rivera WL, Adao DEV. Identification of the 18S-ribosomal-DNA genotypes of Acanthamoeba isolates from the Philippines. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2009; 102:671-7. [PMID: 19000384 DOI: 10.1179/136485908x337544] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyst morphology has been commonly used to identify the free-living amoeba Acanthamoeba to subgenus level. A more accurate and consistent method, based on the sequence analysis of the gene coding for the amoeba's small-subunit ribosomal RNA (Rns), has, however, been developed. There have been no attempts to identify the Acanthamoeba genotypes circulating in the Philippines. In this study, therefore, the ASA.S1 region of the Rns gene from 17 Acanthamoeba isolates, collected from soil, water and contact-lens storage cases in different regions of the Philippines, was sequenced. After the isolates were genotyped, using the BLAST program, their phylogenetic positions relative to known Acanthamoeba isolates were determined. For this, the model-based (GTR + Gamma) neighbour-joining, maximum-likelihood and Bayesian-inference analyses and the non-model-based maximum-parsimony analysis were used. All but two of the isolates were identified as the T5 or T4 genotypes, which are probably common in soil, water and contact-lens cases across the Philippines. The only other genotypes identified were T15 (as a single isolate from a contact-lens case) and T3 (as a single soil isolate).
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Affiliation(s)
- W L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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14
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Ultrastructural study of a tetratrichomonad isolated from pig fecal samples. Parasitol Res 2008; 103:1311-6. [PMID: 18682985 DOI: 10.1007/s00436-008-1134-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
Abstract
Trichomonads found in pigs include the commensal Tritrichomonas suis (more well known because of its synonymy to Tritrichomonas foetus, a trichomonad parasite of cattle and other animals) and Tetratrichomonas buttreyi, which appear similar to Tritrichomonas suis under the light microscope. A trichomonad isolated from pig fecal samples was subjected to scanning and transmission electron microscopy for ultrastructural study. The organism's ultrastructure revealed features commonly found in trichomonads; however, features such as the number and length of flagella, type of undulating membrane, general body form, and shape and location of organelles such as the nucleus, Golgi complex, and hydrogenosomes indicated that the isolated trichomonad is not Tritrichomonas suis nor Tritrichomonas foetus. Polymerase chain reaction (PCR) corroborated these results. Moreover, the ultrastructure was similar to the ultrastructure of previously described tetratrichomonads. It is especially suggested that the isolate is T. buttreyi. These findings could be of significance in the differentiation among different porcine trichomonads in diagnostic procedures. In addition, this is the first known detailed ultrastructural study of T. buttreyi isolated from pigs; thus, this can serve as an aid for future comparison between porcine and bovine T. buttreyi.
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15
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Fotedar R, Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Laboratory diagnostic techniques for Entamoeba species. Clin Microbiol Rev 2007; 20:511-32, table of contents. [PMID: 17630338 PMCID: PMC1932757 DOI: 10.1128/cmr.00004-07] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Entamoeba contains many species, six of which (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba polecki, Entamoeba coli, and Entamoeba hartmanni) reside in the human intestinal lumen. Entamoeba histolytica is the causative agent of amebiasis and is considered a leading parasitic cause of death worldwide in humans. Although recent studies highlight the recovery of E. dispar and E. moshkovskii from patients with gastrointestinal symptoms, there is still no convincing evidence of a causal link between the presence of these two species and the symptoms of the host. New approaches to the identification of E. histolytica are based on detection of E. histolytica-specific antigen and DNA in stool and other clinical samples. Several molecular diagnostic tests, including conventional and real-time PCR, have been developed for the detection and differentiation of E. histolytica, E. dispar, and E. moshkovskii in clinical samples. The purpose of this review is to discuss different methods that exist for the identification of E. histolytica, E. dispar, and E. moshkovskii which are available to the clinical diagnostic laboratory. To address the need for a specific diagnostic test for amebiasis, a substantial amount of work has been carried out over the last decade in different parts of the world. The molecular diagnostic tests are increasingly being used for both clinical and research purposes. In order to minimize undue treatment of individuals infected with other species of Entamoeba such as E. dispar and E. moshkovskii, efforts have been made for specific diagnosis of E. histolytica infection and not to treat based simply on the microscopic examination of Entamoeba species in the stool. The incorporation of many new technologies into the diagnostic laboratory will lead to a better understanding of the public health problem and measures to control the disease.
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Affiliation(s)
- R Fotedar
- St. Vincent's Hospital, Department of Microbiology, Sydney, Darlinghurst, NSW 2010, Australia
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16
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Yason JADL, Rivera WL. Genotyping of Giardia duodenalis isolates among residents of slum area in Manila, Philippines. Parasitol Res 2007; 101:681-7. [PMID: 17401723 DOI: 10.1007/s00436-007-0533-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 03/15/2007] [Indexed: 11/27/2022]
Abstract
Giardia duodenalis is a flagellated protist that causes gastrointestinal disease throughout the world. In the Philippines, study on G. duodenalis is limited. It is also believed that prevalence rates of this organism in the country are underestimated. In this study, stool samples from residents living in a slum area in Manila were collected. These were examined under microscopy for identification of common helminthic and protistan parasites. Results showed that 22.05% of 2,354 stool samples collected contained Giardia cysts. A fraction of samples (n = 133) positive for Giardia cysts were set aside. Genomic DNA was extracted from these samples and a polymerase chain reaction-restriction fragment length polymorphism procedure based on the organism's triose phosphate isomerase gene was utilized. This particular procedure is capable of distinguishing assemblages or genotypes within G. duodenalis. The highest identified assemblage was Assemblage B (86.47%). The two genotypes of Assemblage A were also detected. This is the first report on the identification of genotypes of G. duodenalis in the Philippines. The results of this study can serve as basis for future control and prevention of giardiasis and parasitism in the country.
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Affiliation(s)
- John Anthony D L Yason
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
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17
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Valido EM, Rivera WL. Colony growth of Philippine isolates of Blastocystis hominis in simplified, soft agar medium. Parasitol Res 2007; 101:213-7. [PMID: 17235545 DOI: 10.1007/s00436-006-0456-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 12/22/2006] [Indexed: 10/23/2022]
Abstract
The agar-cloning technique of Blastocystis hominis has been observed in both solid and semisolid agar using Iscove's modified Dulbecco's medium. In this study, Philippine isolates of B. hominis were grown by pour-plate method in semisolid agar using Locke's solution. Inoculated plates contained 0.7% agar, 10% horse serum, and 0.1% sodium thioglycollate. Plates were incubated at 37 degrees C in a microaerophilic jar for 7-10 days. Biconvex disk-shaped colonies were seen abound at the bottom half of the medium. Colonies growing at the agar-glass interface were flat and consisted of thin layers of cells. From these colonies, large amoeboid cells were frequently seen on the periphery, whereas smaller cells were concentrated at the core. Analysis of the SSU rDNA genetically established the identity of the clones to be B. hominis. This is the first report on agar cloning of Blastocystis in a compound medium.
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Affiliation(s)
- Ezra M Valido
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
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18
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Paul J, Srivastava S, Bhattacharya S. Molecular methods for diagnosis of Entamoeba histolytica in a clinical setting: an overview. Exp Parasitol 2006; 116:35-43. [PMID: 17189632 PMCID: PMC4247990 DOI: 10.1016/j.exppara.2006.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 10/13/2006] [Accepted: 11/08/2006] [Indexed: 11/19/2022]
Abstract
The range of clinical outcomes following Entamoeba histolytica infection is likely to be influenced by the different strains of the parasite already existing in our population. There is a need for developing faster, reliable and reproducible methods for identifying the different strains of E. histolytica. This would have a major impact on the subsequent course of treatment given to patients. In the post-genomic era, different loci of the Entamoeba genome have been targeted for developing suitable probes and genetic markers. This review highlights the development made in this direction and the possibility of using these methods for routine testing of this parasite in clinical samples.
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Affiliation(s)
- Jaishree Paul
- Jawaharlal Nehru University, School of Life Sciences, Delhi 110067, India.
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19
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Rivera WL, Santos SR, Kanbara H. Prevalence and genetic diversity of Entamoeba histolytica in an institution for the mentally retarded in the Philippines. Parasitol Res 2005; 98:106-10. [PMID: 16284779 DOI: 10.1007/s00436-005-0024-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 09/20/2005] [Indexed: 10/25/2022]
Abstract
A total of 113 mentally retarded patients residing in a mental institution in Metropolitan Manila, Philippines, were screened for the presence of Entamoeba histolytica based on microscopy and polymerase chain reaction (PCR). Anti-E. histolytica antibodies were also screened in 97 serum samples collected using immunofluorescence antibody (IFA) test. Parasitological examination showed E. histolytica/Entamoeba dispar in 43 cases (38.05%), while PCR detected 74 cases (65.48%) positive for E. histolytica and 6 cases (5.30%) positive for E. dispar. Interestingly, these 6 samples were coinfected with E. histolytica. IFA test revealed that 80.41% (78/97) of the respondents possessed significant antibody titers for intestinal infection of E. histolytica. Of this number, there were 5 patients negative in IFA test but positive in PCR. The genetic diversity of E. histolytica isolates was also investigated by analyzing polymorphism in the serine-rich gene by nested PCR on DNA directly extracted from stool specimens. A combination of the nested PCR results and the AluI digestion of the PCR products examined yielded six distinct DNA banding patterns among the 74 stool isolates. An apparent clustering of E. histolytica strains was observed in patients living in different residential cottages of the institution. These results indicate the high prevalence of E. histolytica in an institution for the mentally retarded in the Philippines.
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Affiliation(s)
- Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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20
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Rivera WL, Tan MAV. Molecular characterization of Blastocystis isolates in the Philippines by riboprinting. Parasitol Res 2005; 96:253-7. [PMID: 15886995 DOI: 10.1007/s00436-005-1344-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Accepted: 02/22/2005] [Indexed: 11/24/2022]
Abstract
Extensive genomic polymorphism has been demonstrated among morphologically identical Blastocystis isolates. To this end, 32 Blastocystis isolates from the Philippines (12 from humans, 12 from pigs and 8 from chickens) were analyzed genetically by riboprinting or restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) amplified small subunit rDNA. Three distinct riboprint patterns were observed from the HinfI digestion, while four patterns resulted from the RsaI digestion of Blastocystis SSU rDNA. Restriction fragment profiles between Blastocystis isolates from different hosts were generally different from each other. However, Blastocystis isolates within each host group were practically the same. Cluster analysis of the riboprint patterns revealed seven distinct groups of the Blastocystis isolates, including a zoonotic strain. These results demonstrate the genetic heterogeneity of Blastocystis in the Philippines and a support to the idea of the organism's zoonotic potential.
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Affiliation(s)
- Windell L Rivera
- Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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21
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Tachibana H, Cheng XJ, Masuda G, Horiki N, Takeuchi T. Evaluation of recombinant fragments of Entamoeba histolytica Gal/GalNAc lectin intermediate subunit for serodiagnosis of amebiasis. J Clin Microbiol 2004; 42:1069-74. [PMID: 15004055 PMCID: PMC356887 DOI: 10.1128/jcm.42.3.1069-1074.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have recently identified a 150-kDa surface antigen of Entamoeba histolytica as an intermediate subunit (Igl) of galactose- and N-acetyl-D-galactosamine-inhibitable lectin, which is a cysteine-rich protein consisting of 1,101 amino acids (aa) and containing multiple CXXC motifs in amino acid sequences. In the present study, full-length Igl except for the signal sequences (aa 14 to 1088) and three fragments of Igl-the N-terminal part (aa 14 to 382), the middle part (aa 294 to 753), and the C-terminal part (aa 603 to 1088)-were prepared in Escherichia coli, and the reactivity of these recombinant proteins with sera from patients with amebiasis was examined by means of enzyme-linked immunosorbent assay (ELISA). Sera from 57 symptomatic patients with amebic liver abscess or amebic colitis, sera from 15 asymptomatic cyst passers, sera from 40 individuals with other protozoan infections, and sera from 50 healthy controls were used. The sensitivity and specificity of the recombinant full-length Igl in the ELISA were 90 and 94%, respectively. When three fragments were used as antigens in the ELISA, the sensitivities were 56% in the N terminus, 92% in the middle part, and 97% in the C terminus. The specificities of the three antigens were 96% in the N terminus and 99% in both the middle and C-terminal fragments. These results demonstrate that Igl is well recognized in not only symptomatic but also asymptomatic patients with E. histolytica infection and that the carboxyl terminus of Igl is an especially useful antigen for the serodiagnosis of amebiasis.
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Affiliation(s)
- Hiroshi Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
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22
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Abstract
The detection of Entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. To assess the scope of E. histolytica infection, it is necessary to utilize accurate diagnostic tools. As more is discovered about the molecular and cell biology of E. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. Molecular biology-based diagnosis may become the technique of choice in the future because establishment of these protozoa in culture is still not a routine clinical laboratory process. In all cases, combination of serologic tests with detection of the parasite (by antigen detection or PCR) offers the best approach to diagnosis, while PCR techniques remain impractical in many developing country settings. The detection of amebic markers in serum in patients with amebic colitis and liver abscess appears promising but is still only a research tool. On the other hand, stool antigen detection tests offer a practical, sensitive, and specific way for the clinical laboratory to detect intestinal E. histolytica. All the current tests suffer from the fact that the antigens detected are denatured by fixation of the stool specimen, limiting testing to fresh or frozen samples.
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Affiliation(s)
- Mehmet Tanyuksel
- Department of Microbiology and Clinical Microbiology, Gulhane Military Medical Academy, Etlik, Ankara 06018, Turkey
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23
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Dagci H, Balcioglu IC, Ertabaklar H, Kurt O, Atambay M. Effectiveness of peptone-yeast extract (P-Y) medium in the cultivation and isolation of Entamoeba histolytica/Entamoeba dispar in Turkish patients. Diagn Microbiol Infect Dis 2003; 45:127-30. [PMID: 12614984 DOI: 10.1016/s0732-8893(02)00508-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amebiasis is a common protozoan infection worldwide, causing serious health problems in both children and adults. Today, almost 10% of the world population is infected with Entamoeba histolytica/Entamoeba dispar. The aims of this study were both the comparison of the reproduction rates and densities of E. histolytica/E. dispar in Robinson, Dobell-Laidlaw and P-Y culture media and isolation of E. histolytica/E. dispar from stool samples in Peptone-Yeast (P-Y) medium. Trophozoites and cysts of E. histolytica/E. dispar, maintained in Robinson medium, and stool samples of patients with amebiasis were inoculated into P-Y, Robinson and Dobell-Laidlaw culture media. Reproduction rates reached their peak levels 48 h after the inoculation in all culture media. Reproduction rates in P-Y and Robinson media were found similar; however, they were higher than the reproduction rate in Dobell-Laidlaw medium (p < 0.01); there was no statistically significant difference between the reproduction rates of P-Y and Robinson media (p > 0.05). Twelve isolates from 12 patients were cultivated in P-Y medium and checked for reproduction everyday for 7 days. Twelve of the 12 (100%) isolates were cultivated in P-Y medium, indicating that the P-Y was an effective medium for the isolation of E. histolytica/E. dispar in stool samples. According to these results, P-Y medium could be preferred in immunologic, serologic and molecular studies and, thus the definitive diagnosis of amebiasis due to its low cost and simple formula.
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Affiliation(s)
- Hande Dagci
- Department of Parasitology, Ege University School of Medicine, Izmir, Izmir, Turkey.
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24
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The diagnostic implications of the separation ofEntamoeba histolytica andEntamoeba dispar. J Biosci 2002. [DOI: 10.1007/bf02704850] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.
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26
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Espinosa-Cantellano M, Martínez-Palomo A. Pathogenesis of intestinal amebiasis: from molecules to disease. Clin Microbiol Rev 2000; 13:318-31. [PMID: 10756002 PMCID: PMC100155 DOI: 10.1128/cmr.13.2.318] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.
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27
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Tachibana H, Cheng XJ. Entamoeba dispar: cloning and characterization of peroxiredoxin genes. Exp Parasitol 2000; 94:51-5. [PMID: 10631082 DOI: 10.1006/expr.1999.4461] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- H Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, 259-1193, Japan.
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28
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29
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Ramos F, Zurabian R, Morán P, Ramiro M, Gómez A, Clark CG, Melendro EI, García G, Ximénez C. The effect of formalin fixation on the polymerase chain reaction characterization of Entamoeba histolytica. Trans R Soc Trop Med Hyg 1999; 93:335-6. [PMID: 10492774 DOI: 10.1016/s0035-9203(99)90045-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Formalin fixation is the most common storage, transportation and preservation method for stool samples. However, fixation dramatically reduces our ability to extract from stool samples DNA that is a suitable template for polymerase chain reaction (PCR)-based diagnostic tests. In this study we evaluated the effects of formalin concentration and of the time stored in fixative on the success of PCR amplification. We found that the deleterious effects of formalin are both time and concentration dependent and may result from fragmentation of fixed DNA during its purification.
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Affiliation(s)
- F Ramos
- Departamento de Medicina Experimental, Facultad de Medicina, UNAM, Mexico
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30
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Andrews RH, Chilton NB. Multilocus enzyme electrophoresis: a valuable technique for providing answers to problems in parasite systematics. Int J Parasitol 1999; 29:213-53. [PMID: 10221624 DOI: 10.1016/s0020-7519(98)00168-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this review is to highlight the effectiveness of the technique of multilocus enzyme electrophoresis in answering questions relating to the systematics of parasites and to highlight errors in the way the technique has been used and the results interpreted. We have approached this topic by answering specific questions that we have been asked by colleagues and students not necessarily familiar with the technique, the method of data analysis and its application. Although the technique has been applied to provide answers for taxonomic and population genetics studies, it remains under-utilised, perhaps because of recent advances in newer molecular technology. Rather than not acknowledge or dismiss the value of more traditional technology, we suggest that researchers examine problems in the systematics of parasites by the comparison of data derived from morphological, biochemical and molecular techniques.
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Affiliation(s)
- R H Andrews
- Department of Microbiology and Immunology, The University of Adelaide, SA, Australia.
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31
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Motta CM, Beltrão EI, Amorim RV, Carvalho Júnior LB. Entamoeba histolytica and Entamoeba dispar in the northeast Brazil. Rev Inst Med Trop Sao Paulo 1997; 39:365-6. [PMID: 9674291 DOI: 10.1590/s0036-46651997000600012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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32
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Tachibana H, Kobayashi S, Kaneda Y, Takeuchi T, Fujiwara T. Preparation of a monoclonal antibody specific for Entamoeba dispar and its ability to distinguish E. dispar from E. histolytica. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1997; 4:409-14. [PMID: 9220156 PMCID: PMC170542 DOI: 10.1128/cdli.4.4.409-414.1997] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A monoclonal antibody (MAb), MAb ED17 (immunoglobulin G2a [IgG2a]), prepared against trophozoites of Entamoeba dispar SAW1734RclAR cultured monoxenically with Crithidia fasciculata, reacted with 25 of 26 isolates of E. dispar by an indirect fluorescent-antibody test. In contrast, the MAb failed to react with any of 20 isolates of E. histolytica or other enteric protozoan parasites. Western blot (immunoblot) analysis showed that the molecular mass of the E. dispar antigen recognized by the MAb was 160 kDa under reduced conditions. Immunoelectron microscopy revealed that the antigen was mainly located on digested C. fasciculata, but not on undigested organisms. Double staining with a mixture of MAb ED17 and MAb 4G6 (an IgG1 MAb which reacts exclusively with E. histolytica), followed by incubation with a mixture of fluorescein isothiocyanate-labeled anti-mouse IgG2a and tetramethylrhodamine isothiocyanate-labeled anti-mouse IgG1 antibodies, simultaneously identified mixed populations of E. dispar and E. histolytica. This method may prove to be useful for the accurate identification of E. dispar and E. histolytica, even in mixed infections.
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Affiliation(s)
- H Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Japan.
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33
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Britten D, Wilson SM, McNerney R, Moody AH, Chiodini PL, Ackers JP. An improved colorimetric PCR-based method for detection and differentiation of Entamoeba histolytica and Entamoeba dispar in feces. J Clin Microbiol 1997; 35:1108-11. [PMID: 9114390 PMCID: PMC232712 DOI: 10.1128/jcm.35.5.1108-1111.1997] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The epidemiological implications of the recent separation of "Entamoeba histolytica" into two separate species, pathogenic E. histolytica sensu stricto and commensal E. dispar, will not become apparent without methods of distinguishing between them which are applicable to large numbers of specimens. We have modified a PCR-based method to produce such a technique which may be completed in 1 day while still identifying 10(-1) E. histolytica and 1 to 10 E. dispar trophozoites per g of feces when present separately and 10 E. histolytica and 100 E. dispar trophozoites per g in the presence of 10(6) trophozoites per g of the other species. Applied to fecal specimens from 18 patients from which E. histolytica or E. dispar had been grown and identified to the species level by hexokinase isoenzyme analysis, the method in every case yielded the correct result. Positive and negative results are easily distinguished by eye, and we are now applying this technique to a large-scale epidemiological study of amebiasis in the eastern Mediterranean region.
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Affiliation(s)
- D Britten
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, United Kingdom
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