Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

Frequency of amoebiasis and other intestinal parasitoses in a settlement in Ilheus City, State of Bahia, Brazil

Introduction: This study evaluated the frequency of intestinal parasites, emphasizing the identification and differentiation of Entamoeba spp. Methods: Multiplex polymerase chain reaction (PCR), coproantigen tests and morphometric analysis were performed for Entamoeba spp. differentiation. Results: The overall frequency of intestinal parasites was 65%. Entamoeba histolytica was detected by the coproantigen test, and the PCR showed that Entamoeba dispar predominated in the population. In contrast, morphometric analysis was important for identifying Entamoeba hartmanni. Conclusions: It is possible to identify the causative agent of amoebiasis and to differentiate this agent from other species by combining techniques. .

Different Clinical Outcomes of Entamoeba histolytica in Malaysia: Does Genetic Diversity Exist?

The present study was conducted to investigate the clinical outcomes of Entamoeba histolytica infection in symptomatic and asymptomatic Orang Asli (aborigine) communities in Malaysia. Examination was performed on 500 stool samples obtained from Orang Asli communities in 3 different states using formalin-ether concentration, trichrome staining, and single-round PCR techniques. Out of 500 stool samples, single infection of E. histolytica, Entamoeba dispar, and Entamoeba moshkovskii was identified in 3.2%, 13.4%, and 1%, respectively. In addition, 10 samples had mixed infections with E. histolytica and E. dispar. Six samples containing E. dispar were also positive for E. moshkovskii, and only 2 samples had E. histolytica in association with E. dispar and E. moshkovskii. Seventeen E. histolytica-positive samples were from symptomatic subjects, whereas the remaining 11 samples came from asymptomatic subjects. These findings suggest a predominant distribution of pathogenic potential of E. histolytica strains in this community. Therefore, further studies on genotyping of E. histolytica is required, to find out association between E. histolytica genotype and the outcome of the infection.

Validation and utilization of PCR for differential diagnosis and prevalence determination of Entamoeba histolytica/Entamoeba dispar in Salvador City, Brazil

Amoebiasis is an infection caused by Entamoeba histolytica and is a potential health risk in countries in which health barriers are inappropriate. Since the discovery of Entamoeba dispar, the prevalence of amoebiasis has been modified. OBJECTIVE: This study has standardized the PCR technique applied for the diagnosis of different species of the E. histolytica/E. dispar complex and has evaluated the prevalence of infection among patients attending private and public clinical laboratories in Salvador City, Bahia State, Brazil. RESULTS: Analysis of 52,704 stool samples by microscopic examination demonstrated that 1,788 (3.4 percent) were positive for the E. histolytica/E. dispar complex and infection occurred more often in samples originated from public clinical laboratories (5.0 percent) than those that came from private laboratories (3.2 percent). PCR performed in approximately 15 percent (262) E. histolytica/E. dispar complex positive samples, randomly chosen, amplified 227 samples (86.6 percent), all of them positive for E. dispar. The non-amplified 35 samples (13.4 percent) were also negative for E. histolytica-specific galactose adhesin. Moreover, to exclude a probable infection caused by E. hartmanni, morphometric analysis demonstrated that non-amplified samples had cyst sizes comparable to E. histolytica/E. dispar (>10 µm). CONCLUSION: The absence of amplification of these samples indicates the presence of PCR inhibitors in the stool samples or the presence of DNA from Entamoeba species other than E. dispar, E. histolytica or E. hartmanni.

Detección y diferenciación de Entamoeba histolytica y Entamoeba dispar mediante reacción en cadena de la polimerasa en individuos de una comunidad del Estado Zulia, Venezuela / Detection and differentiation of Entamoeba histolytica and Entamoeba dispar by polymerase chain reaction in a community in Zulia State, Venezuela

Differential identification of Entamoeba histolytica and Entamoeba dispar is essential for both appropriate patient treatment and epidemiological purposes. To determine the prevalence of these amoeba infections in Santa Rosa de Agua (Maracaibo, Zulia State, Venezuela), a PCR assay using specific primers for each species was standardized and applied. 204 stool samples were analyzed through direct microscopic examination with SSF (0.85 percent) and lugol, formol-ether concentration, and PCR. Under direct microscopy, 42 individuals (20.58 percent) presented the E. histolytica/E. dispar complex. Meanwhile PCR showed 47 positive cases for these amoebas: 22 E. histolytica (10.78 percent), 16 E. dispar (7.84 percent), and 9 (4.41 percent) mixed infections. There was no significant difference in the presence of E. histolytica and/or E. dispar according to either gender or age. There were no cases of these amoebas in children under 2 years of age. Observed frequency of E. histolytica (31/204) shows the endemic nature of amoeba infection in this community.

La identificación diferencial de Entamoeba histolytica y Entamoeba dispar es esencial para un tratamiento adecuado del paciente y con fines epidemiológicos. Para determinar la prevalencia de E. histolytica y E. dispar se estandarizó y aplicó un ensayo de PCR, utilizando oligonucleótidos específicos para cada especie. 204 muestras de heces de individuos de la comunidad de Santa Rosa de Agua (Municipio Maracaibo, Estado Zulia, Venezuela), fueron analizadas a través del examen directo con SSF (0,85 por ciento) y lugol, concentrado de formol-éter y PCR. Al examen microscópico, 42 individuos (20,58 por ciento) presentaron formas evolutivas del complejo E. histolytica/E. dispar; mientras que la técnica de PCR evidenció un total de 47 casos positivos a estas amibas; de los cuales 22 eran portadores de E. histolytica (10,78 por ciento), 16 (7,84 por ciento) de E. dispar y 9 (4,41 por ciento) presentaron infección mixta. No hubo diferencia significativa al relacionar las variables sexo y presencia de E. histolytica y/o E. dispar, ni con los grupos etarios. No existieron casos de estas amibas, en los menores de 2 años. La frecuencia observada de E. histolytica (31/204), demuestra el carácter endémico de la amibiasis en esta comunidad.

Prevalencia y asociación epidemiológica de los protozoarios orales Entamoeba gingivalis y Trichomonas tenax en niños mexicanos / Prevalence and epidemiological association of the Entamoeba gingivalis and Trichomonas tenax oral protozoa in Mexican children

Existen pocos estudios sobre protozoarios de la cavidad oral en niños. Algunos estudios sugieren su probable patogenicidad. Objetivo: Determinar la prevalencia de protozoarios orales en niños mexicanos y su asociación con edad, género, grado de higiene oral y enfermedad periodontal. Material y métodos: Se estudiaron 150 niños de 3 a 14 años de edad. Los protozoarios orales se detectaron en el sedimento de enjuagues bucales por examen en fresco y tinción tricrómica. Resultados: El 8.7 por ciento fueron positivos para E. gingivalis; 12.7 por ciento para T. tenax y 1.3 por ciento con ambos. La prevalencia global fue de 22.7 por ciento. Se encontró asociación con edad y enfermedad periodontal, pero no con género. Conclusiones: La frecuencia de T. tenax es muy elevada al compararla con reportes similares.

Implantação e avaliação do diagnóstico diferencial entre Entamoeba histolytica e Entamoeba dispar em amostras fecais / Implementation and evaluation of the differential diagnosis of Entamoeba histolytica and Entamoeba dispar in fecal samples

A amebíase é uma infecção causada pela Entamoeba histolytica e representa um risco em potencial à saúde, em quase todos os países onde as barreiras sanitárias são inadequadas. É a segunda causa de mortalidade entre as parasitoses, alcançando em torno de 100.000 óbitos anuais. Com a descoberta da Entamoeba dispar, organismo comensal morfologicamente idêntico e geneticamente distinto da E. histolytica, a prevalência da infecção tem sido modificada. Neste estudo foi padronizada a reação em cadeia da polimerase para diagnóstico específico das amebas do complexo E. histolytica/E. dispar e aplicada para avaliar a prevalência da infecção em indivíduos atendidos em laboratórios da rede privada e pública de Salvador-BA. Amostras fecais de 52.704 pacientes, provenientes de 27 postos de coleta distribuídos em várias localidades, foram submetidas a exames coproparasitológicos. As amostras positivas para o complexo E. histolytica/E. dispar (n= 262) tiveram seus cistos concentrados por meio da técnica de formol-éter para posterior extração do DNA e diagnóstico através da PCR. Foi observada uma prevalência de 3.4 por cento para o complexo E. histolytica/E. dispar, sendo mais freqüente nas amostras provenientes do serviço público de saúde (5.0 por cento) do que naquelas do serviço privado (3.2 por cento). Através da PCR foi demonstrado que 86.6 por cento destes pacientes estavam verdadeiramente infectados pela E. disparo. Para o restante dos pacientes (14.4 por cento), a PCR foi negativa tanto para E. histolytica como para E. disparo. No ensaio imunoenzimático foi confirmado que estes pacientes não estavam infectados pela E. histolytica e o estudo morfométrico mostrou que o tamanho dos cistos é compatível com as amebas do complexo, afastando a possibilidade de infecção por E. hartmanni. Possivelmente, a presença de inibidores enzimáticos nas fezes diminuiu a sensibilidade da PCR. No entanto, é uma metodologia eficaz para...

Ocorrência de Entamoeba histolytica/Entamoeba dispar em pacientes ambulatoriais de Recife, PE / Occurrence of Entamoeba histolytica/Entamoeba dispar in ambulatory patients of Recife, PE

Este trabalho teve como objetivo determinar a ocorrência das espécies Entamoeba histolytica/Entamoeba dispar em amostras clínicas de pacientes ambulatoriais de Pernambuco. Neste estudo, foi utilizado o teste imunoenzimático específico para Entamoeba histolytica, que entre os 213 pacientes não identificou nenhuma amostra fecal positiva. Estes resultados confirmam Entamoeba dispar é a espécie dominante nesta região.

The objective this study was to determine the occurrence of the species Entamoeba histolytica/Entamoeba díspar in clinical samples of ambulatory patients in Pernambuco. A specific assay for Entamoeba histolytica was used in this study, which identified no positive fecal samples among the 213 patients. These results confirm that E. dispar is the dominant species in Pernambuco State.

Comparative evaluation of hexokinase isoenzyme typing and antigen detection for differentiation of Entamoeba histolytica and Entamoeba dispar.

Entamoeba histolytica, the causative organism of invasive amebiasis is a potential pathogen, while asymptomatic infection is caused by E. dispar. Differentiation of the species is not possible on the basis of morphological characters by microscopic examination. In the present study an attempt has been made to differentiate E. histolytica from E. dispar in 45 isolates obtained from culture and direct stool samples respectively on the basis of hexokinase isoenzyme analysis and Tech Lab ELISA. A 100% correlation was found between these two techniques. However, Tech Lab E. histolytica antigen detection test was found to be both rapid and technically simple. Its use in diagnosis and epidemiological studies is recommended.

System of 14C-glucose incorporation in axenic cultures of Entamoeba invadens: IP-1 strain

Background. It has been described that the walls of the amebic cyst from Entamoeba invadens are composed mainly of chitin, a polysaccharide of amino-sugars. It is also know that the synthesis of this polysaccharide is closely related to the degradation of the intracellular glycogen in this organisms. Nevertheless, it is not know whether the intracellular glycogen is really the source of the glucose requirements for the synthesis of the cell wall. Methods. To determine the relationship between the wall cyst synthesis and glycogen degradation, it was considered to develop an in vitro culture cell system to label this polysaccharide with radioactive glucose. In this study, a system of 14C-glucose incorporation in axenic cultures of E. invaden was developed. The experiments in the study were carried out to recognize if an increase occurred in the 14C-glucose incorportation into ameba when the amount of the radioctivity used was increased, or whether this incorporation is a dependent metabolic stage. Results. The results showed that the amount of glucose incorportation reached similar values of 4.5 x 10-12 mmol per cell in both cases. A differente slope in the glucose kinetic incorporation between the cultures previously subjected to glucose depletion and the standard cultures was observed. Conclusions. This axenic method of radioactive glucose incorporation in Entamoeba invadens could facilitate the analysis on a greater scale of the metabolism of this nutrient

Differentiation of pathogenic and non-pathogenic Entamoeba: has the question been answered?

Pathogenic and non-pathogenic Entamoeba have been separated into two distinct species. Recently, the non-pathogenic E. dispar has been cultivated axenically. However, the genetic variability among different clones from the same strain, experimental production of hybrid clones which may differ from their parents, and the possibility of invasiveness of E. dispar, are some phenomena which may indicate that the last word on distinctiveness of the species has not yet been said.

Blastocystis hominis: prevalencia en alumnos de una escuela básica. Maracaibo, Estado Zulia, Venezuela / Blastocystics hominis: prevalence in scholars from basic school Maracaibo, Zulia State, Venezuela

Para determinar la prevalencia del Blastocystic hominis se estudiaron 150 escolares de ambos sexos, aparentemente sanos, cuyas edades oscilaban entre 6 y 14 años que cursan en la Escuela Básica "Dr. Nestor Luis Pérez". Municipio Maracaibo, Estado Zulia, Venezuela. Se recolectó una muestra fecal por alumno a la cual se le practicó un examen al fresco con solución salina, coloración temporal con lugol y la técnica de concentración formol-éter. La prevalencia de B.hominis fue de 24,0 por ciento; al relacionar las variables parasitosis, edad, grado de instrucción y sexo y aplicarle la prueba de significancia estadística del Chi cuadrado, se observó dependencia significativa entre parasitosis-edad parasitosis grado de instrucción y una relación de independencia entre parasitosis-sexo. B.hominis se encontró asociación a otras especies de enteroparásitos en un 55.6 por ciento, al aplicar el índice de Fager y la prueba de "t" se demostró asociación significativa entre B.hominis con Endolimax nana y B.hominis con Entamoeba coli. Los resultados obtenidos revelan que la frecuencia de B.hominis es alta, por lo que se considera importante su informe en los exámenes de heces, continuar con los estudios sobre patogenicidad y realizar campañas de educación sanitaria en la población

Host tissue destruction by Entamoeba histolytica: molecules mediating adhesion, cytolysis, and proteolysis

Entamoeba histolytica, the protozoan parasite causing human amoebisis, has recently been found to comprise two genetically distinct forms, potentially pathogenic and constitutively nonpathogenic ones. Host tissue destruction by pathogenic forms is belived to result from cell functions mediaed by a lectin-type adherence receptor, a pore-forming peptide involved in host cell lysis, and abundant expression of cysteine proteinase(s). Isolation and molecular cloning of these amoeba products have provided the tools for structural analyses and manipulations of cell functions including comparisons between pathogenic and nonpathogenic forms