Perforación intestinal secundaria a amebiasis / Amebiasis intestinal perforation secondary

La amebiasis intestinal es una enfermedad frecuente en países en desarrollo, que es común en regiones tropicales y subtropicales, así como en regiones con servicios sanitarios deficientes. Presentamos el caso de un paciente de 74 años de edad, sexo masculino, originario y residente de la ciudad de Guatemala, quién cursó una diarrea y dolor abdominal. Fue intervenido quirúrgicamente por abdomen agudo, con resección intestinal extensa por perforaciones. En el estudio de anatomía patológica se realizó el diagnóstico de colitis amebiana con perforaciones y peritonitis.

Intestinal amoebiasis is a disease common indeveloping countries, which is common in tropicaland subtropical regions, as well as in regions withpoor sanitation. We report the case of a 74-year-oldmale, resident of Guatemala City, who presented withdiarrhea and abdominal pain. He had a laparatomy foracute abdomen, undergoing wide intestinal resectiondue to perforations. The pathology diag-nosis wasamoebic colitis with perforations and peritonitis.

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.

Historia del protozoo Entamoeba histolytica: [revisión] / History of the Entamoeba histolytica protozoan: [review]

This article presents a history of Entamoeba histolytica spanning since the remote times when it was not even recognized as a cause of human disease to the recent molecular advances. Feder Losch (1875) in Saint Petersburg, found amoebae in fecal samples but only regarded them as responsible for maintaining the inflammatory process, not as a cause of dysentery. Fritz Schaudinn (1903) established the differentiation between Entamoeba histolytica and Endamoeba coli, Schaudinn decided to call it E. histolytica because of its ability to cause tissue lysis. Emile Brumpt (1925) based on experimental studies, pointed out the existence ofE. Histolytica as a species complex, comprising two morphologically indistinguishable species, E. dysenteríae which is the cause of symptomatic infection, and Entamoeba dispar found only in asymptomatic carriers. Louis Diamond et al (1961) during the 1960s developed an axenic culture medium for E. histolytica which allowed in vivo and in vitro studies. Sargeaunt and Williams (1978) distinguished for the first time E. histolytica strains by isoenzyme electrophoresis, thus confirming thatE. hystolytica was indeed a species complex comprising both pathogenic and non-pathogenic species. William Petri et al (1987 demonstrated that the 170 kDa protein with greater antigenicity was the Gal/GalNac-specific lectin. Diamond and Clark (1993) described again Brumpt's original 1925hypothesis, concluding that there was enough evidence to support the existence of two morphologically indistinguishable species, a pathogenic and a nonpathogenic one, corresponding to E. histolytica and Entamoeba dispar respectively. The World Health Organization accepted this hypothesis in 1997.

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.

Role of DNA probes in characterization of pathogenic and non-pathogenic E. histolytica.

Various tests have been described to differentiate the pathogenic and non-pathogenic types of E. histolytica. Recently DNA hybridization has been described to differentiate between the two subtypes. Using common HMC probe the presence of E. histolytica in stool was confirmed. Then on the basis of hybridization with DNA probe P 145 (pathogenic) and B 133 (non-pathogenic) E. histolytica was characterized as being pathogenic and non pathogenic respectively. Out of 137 patients studied 88 were symptomatic and 49 asymtomatic. 65 patients harboured E. histolytica as proved by microscopic examination of stool. Sixty-eight stool samples tested positive for DNA hybridization with common HMC probe, this included 65 microscopy positive samples and 3 microscopy negative samples. This gives a sensitivity of 100% and 96% specificity. All the 68 samples were then subjected to hybridization with P 145 and B 133 DNA probes. Out of 88 symptomatic patients stool samples of 57 patients were microscopy positive, however 58 were positive by common HMC probe and all of these were P 145 (pathogenic) positive and B 133 (non-pathogenic) negative. Of the 49 asymptomatic cases 8 were E. histolytica positive on microscopy and 10 positive on hybridization with common HMC probe and all 10 were P 145 negative and B 133 positive. It can be thus concluded that DNA hybridization is a reliable way to differentiate between pathogenic and nonpathogenic E. histolytica.

Amibiasis intestinal invasora: Patogenia

Las personas que albergan trofozoitos de Entamoeba histolytica no patógena (actualmente denominada Entamoeba dispar) nunca desarrollan formas invasoras de amibiasis, y además, nunca es posible encontrar en su suero antígenos amibianos, razón por la cual tampoco desarrollan una respuesta inmunitaria con producción de anticuerpos antiamibianos. Por el contrario, en aquellas personas que albergan trofozoitos de Entamoeba histolytica patógena si es posible encontrar en el suero antígenos amibianos y evidencia inmunológica del desarrollo de una respuesta del huésped a los mismos; además, desde el punto de vista clínico, estas personas pueden permanecer asintomáticas, según sea la correlación de fuerzas entre parásito, huésped y medio ambiente, dando lugar al estado de portador asintomático cuyas implicaciones clínicas, diagnósticas y terapéuticas fueron revisadas en la pasada entrega de esta revista, o bien pueden desarrollar una amibiasis intestinal invasora cuya patogenia constituye el tema del presente artículo. En una futura entrega se revisará el tema de los síndromes clínicos, diagnóstico y tratamiento de la amibiasis intstinal invasora y de la amibiasis extraintestinal

Axenic cultivation of Entamoeba histolytica from liver abscess and its zymodeme.

A local strain of Entamoeba histolytica, the HTH-56: MUTM from a human liver abscess was successfully axenized. The culture was initially established monoxenically in Diamond's TYI-S-33 medium in the presence of Crithidia luciliae and maintained at 34 +/- 0.5 degrees C. After 5 passages it was adapted to axenic cultivation by addition of 0.02% Bacto agar in Diamond's TYI-S-33 medium in place of Crithidia. Subcultures or replacement with fresh complete media were done twice or thrice for 7 days, after which the agar was omitted and a stable culture was obtained. Isoenzyme analysis showed that this strain of E. histolytica belonged to the zymodeme II pattern, which is one out of 10 pathogenic zymodemes of E. histolytica most commonly found among the virulent strains.

Isoenzyme pattern of clones of Entamoeba histolytica.

The isoenzyme pattern of clones of E. histolytica isolated from symptomatic and asymptomatic patients of amoebiasis were determined by starch gel electrophoresis. Ten parent cultures (uncloned), 5 from symptomatic and 5 from asymptomatic patients were isolated and established in Robinsons medium as xenic cultures. A total of 100 clones were isolated from parent cultures but only 65 could be established. Starch gel electrophoresis was carried out on the uncloned and cloned cultures. The analysis showed that the 5 uncloned culture from symptomatic patients had 4 isolates with pathogenic zymodeme and 1 isolate with non-pathogenic zymodeme pattern. The presence of beta band and absence of alpha band for phosphoglucomutase (PGM) and a fast moving Hexokinase (HK) band were taken as markers of pathogenicity. The 5 cloned cultures from asymptomatic patients had three isolates with pathogenic and 2 with non-pathogenic pattern. The cloned isolates from symptomatic patients (35) had 20 pathogenic zymodemes and asymptomatic patients (30) had 15 pathogenic zymodemes. Non-pathogenic zymodeme obtained in the present study were I, IV, V, X and XIII and the pathogenic zymodemes obtained were II and XIV. The data of the study indicated that (i) asymptomatic patients also harbour pathogenic zymodemes; and (ii) zymodeme II also coexsist with zymodeme XIV in the Indian population.