RESUMO
Amoebiasis is a disease caused by Entamoeba histolytica, affecting the large intestine of humans and occasionally leading to extra-intestinal lesions. Entamoeba dispar is another amoeba species considered commensal, although it has been identified in patients presenting with dysenteric and nondysenteric colitis, as well as amoebic liver abscess. Amoebic virulence factors are essential for the invasion and development of lesions. There is evidence showing that the association of enterobacteria with trophozoites contributes to increased gene expression of amoebic virulence factors. Enteropathogenic Escherichia coli is an important bacterium causing diarrhea, with high incidence rates in the world population, allowing it to interact with Entamoeba sp. in the same host. In this context, this study aims to evaluate the influence of enteropathogenic Escherichia coli on ACFN and ADO Entamoeba dispar strains by quantifying the gene expression of virulence factors, including galactose/N-acetyl-D-galactosamine-binding lectin, cysteine proteinase 2, and amoebapores A and C. Additionally, the study assesses the progression and morphological aspect of amoebic liver abscess and the profile of inflammatory cells. Our results demonstrated that the interaction between EPEC and ACFN Entamoeba dispar strains was able to increase the gene expression of virulence factors, as well as the lesion area and the activity of the inflammatory infiltrate. However, the association with the ADO strain did not influence the gene expression of virulence factors. Together, our findings indicate that the interaction between EPEC, ACFN, and ADO Entamoeba dispar strains resulted in differences in vitro and in vivo gene expression of Gal/GalNAc-binding lectin and CP2, in enzymatic activities of MPO, NAG, and EPO, and consequently, in the ability to cause lesions.
Assuntos
Entamoeba , Escherichia coli Enteropatogênica , Fatores de Virulência , Escherichia coli Enteropatogênica/patogenicidade , Escherichia coli Enteropatogênica/genética , Entamoeba/patogenicidade , Entamoeba/genética , Entamoeba/fisiologia , Fatores de Virulência/genética , Virulência , Animais , Camundongos , Abscesso Hepático Amebiano/parasitologia , Entamebíase/parasitologia , Humanos , Expressão GênicaRESUMO
Intestinal mucins are the first line of defense against microorganisms. Although knowledge about the mechanisms involved in the establishment of intestinal protozoa is limited, there is evidence that these parasites produce lectin-like molecules and glycosidases, that exert both, constitutive and secretory functions, promoting the establishment of these microorganisms. In the present review, we analyse the main interactions between mucins of the host intestine and the four main protozoan parasites in humans and their implications in intestinal colonization. There are lectin-like molecules that contain complex oligosaccharide structures and N-acetylglucosamine (GlcNAc), mannose and sialic acid as main components, which are excreted/secreted by Giardia intestinalis, and recognized by the host using mannose-binding lectins (MBL). Entamoeba histolytica and Cryptosporidium spp. express the lectin galactose/N-acetyl-D-galactosamine, which facilitates their adhesion to cells. In Cryptosporidium, the glycoproteins gp30, gp40/15 and gp900 and the glycoprotein lectin CpClec are involved in protozoan adhesion to intestinal cells, forming an adhesion-attack complex. G. intestinalis and E. histolytica can also produce glycosidases such as ß-N-acetyl-D-glucosaminidase, α-d-glucosidase, ß-d-galactosidase, ß-l-fucosidase, α-N-acetyl-d-galactosaminidase and ß-mannosidase. In Blastocystis, α-D-mannose, α-D-glucose, GlcNAc, α-D-fucose, chitin and sialic acid that have been identified on their surface. Fucosidases, hexosaminidases and polygalacturonases, which may be involved in the mucin degradation process, have also been described in the Blastocystis secretoma. Similarly, symbiotic coexistence with the intestinal microbiota promotes the survival of parasites facilitating cell invasion and nutrients obtention. Furthermore, it is necessary to identify and characterize more glycosidases, which have been only partially described by in silico analyses of the parasite genome.
Assuntos
Criptosporidiose , Cryptosporidium , Glicoproteínas , Mucinas , Parasitos , Animais , Criptosporidiose/parasitologia , Cryptosporidium/parasitologia , Entamoeba/patogenicidade , Glicoproteínas/metabolismo , Glicosídeo Hidrolases , Humanos , Intestinos/microbiologia , Lectinas , Parasitos/patogenicidadeRESUMO
Recent studies have shown how intestinal parasites can modulate gut microbiota. This observation is not surprising since the human intestinal lumen, like any other niche, is a battlefield of microbial competition, and Eukaryotes can affect bacterial populations. Intestinal pathogenic protist has been associated with reshaping the microbial community structure; however, the interactions between the colonic bacterial communities and parasites like Blastocystis spp., Entamoeba coli, and Endolimax nana have been poorly studied. In this work, we studied the distal intestinal bacterial microbiota of 49 children attending 7 public daycare centers in Medellin, Colombia, and compared the bacterial microbiota structure in the presence or absence of the protists Blastocystis spp., E. coli, and E. nana. Parasite colonization was associated with an increase in bacterial richness. Moreover, Blastocystis spp. presented a positive relationship with Prevotella, since this bacterium was selectively enriched in children carrying it. Remarkably, the E. coli colonized children showed a microbial profile that was closer to uninfected controls, although some bacterial taxa displayed to be enriched. This is the case for Akkermansia, which showed to be favored in E. coli colonized individuals, while notably reduced in the Blastocystis spp. parasitized group.
Assuntos
Amebíase/microbiologia , Fezes/parasitologia , Microbioma Gastrointestinal/fisiologia , Bactérias/genética , Blastocystis/patogenicidade , Infecções por Blastocystis/microbiologia , Pré-Escolar , Colômbia , Endolimax/patogenicidade , Entamoeba/patogenicidade , Entamebíase/microbiologia , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/genética , Humanos , Lactente , Enteropatias Parasitárias/microbiologia , Enteropatias Parasitárias/parasitologia , Masculino , Prevotella/genéticaRESUMO
It has been claimed that amoebic molecules such as amoebapore, galactose/N-acetyl galactosamine inhibitable lectin, and cysteine proteases are responsible for host tissue destruction and are present in both pathogenic Entamoeba histolytica and non-pathogenic Entamoeba dispar. Some reports have provided evidence that after infection with E. dispar, pathological changes may occur in some humans. The aim of this study was to evaluate E. dispar pathogenicity by comparing it to the pathogenicity of E. histolytica through liver abscesses induced in hamsters. Syrian golden hamsters were challenged by intrahepatic inoculation with the 03C E. dispar strain or with two strains of E. histolytica (HM1:IMSS and EGG) to compare their virulence grades. As control groups, we used bacterial flora and Pavlova's modified medium. Lesions were verified at 1, 3 and 6 days after inoculation. Multiplex Polymerase Chain Reaction was performed to characterize each strain using EdP1/EdP2 and EhP1/EhP2 primers. The EGG and HM1:IMSS E. histolytica strains and 03C E. dispar were able to cause liver lesions. The EGG strain caused extensive hepatic abscesses, and trophozoites were found in the lesions throughout the three periods of study. The HM1:IMSS strain caused smaller abscesses when compared to EGG lesions; however, trophozoites were observed at 1 and 3 days after inoculation. The 03C E. dispar strain caused intermediate abscesses when compared to the others; trophozoites were observed in all periods analyzed. The EGG strain caused progressive evolution of the injury, which differed from the HM1:IMSS and 03C strains. These results strongly suggest that the 03C E. dispar strain is pathogenic in the experimental hamster model. Additional studies are necessary to identify potential factors that regulate the manifestation of virulence of this strain and others.
Assuntos
Entamoeba/patogenicidade , Abscesso Hepático Amebiano/parasitologia , Animais , Peso Corporal , Brasil , Cricetinae , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , Modelos Animais de Doenças , Entamoeba/classificação , Entamoeba/genética , Feminino , Humanos , Fígado/parasitologia , Fígado/patologia , Abscesso Hepático Amebiano/patologia , Masculino , Mesocricetus , Reação em Cadeia da Polimerase Multiplex , Tamanho do ÓrgãoRESUMO
During the last decade Entamoeba moshkovskii has become relevant given its capacity to infect humans, especially when considering that it is morphologically indistinguishable from E. histolytica. For a long time, E. moshkovskii was considered as a free living amoeba, but in the last decade it has been demonstrated that E. moshkovskii can infect humans and can be found more frequently in regions where amebiasis shows high prevalence values, becoming a challenge to differentiate it from the E. histolytica/E. dispar complex. Recently there have been studies that raise the possibility that E. moshkovskii could be a pathogenic species, as there are reports in different countries that associated this infection with gastrointestinal symptoms even though others have described it as a non pathogenic species. For this reasons, both clinical and epidemiological studies are required.
Assuntos
Entamoeba/classificação , Entamoeba/isolamento & purificação , Entamebíase/diagnóstico , Entamebíase/parasitologia , Entamoeba/patogenicidade , Entamebíase/epidemiologia , HumanosRESUMO
The rapid redistribution of surface antigen-antibody complexes in trophozoites of the human protozoan parasite Entamoeba histolytica, in a process known as capping, has been considered as a means of the parasite to evade the host immune response. So far, capping has been documented in the invasive E. histolytica, whereas the mobility of surface components in the non-invasive Entamoeba dispar is not known. E. dispar does not induce liver lesions in rodent experimental models, in contrast to the liver abscesses produced by E. histolytica in the same animal model. We have therefore analyzed the mobility of surface receptors to the lectin concanavalin A and of Rab11, a membrane-associated protein, in both species of Entamoebae by confocal fluorescence microscopy and transmission and scanning electron microscopy. The great majority of E. histolytica trophozoites became morphologically polarized through the formation of well-defined caps at the posterior pole of the parasite. Actin colocalized with the lectin caps. Antibodies against the membrane protein Rab 11 also produced capping. In striking contrast, in E. dispar, the mobility of concanavalin A surface receptors was restricted to the formation of irregular surface patches that did no progress to constitute well-defined caps. Also, anti-Rab 11 antibodies did not result in capping in E. dispar. Whether the failure of E. dispar to efficiently mobilize surface molecules in response to lectin or antibodies as shown in the present results is related to its non-invasive character represents an interesting hypothesis requiring further analysis.
Assuntos
Antígenos de Protozoários/metabolismo , Entamoeba/patogenicidade , Animais , Concanavalina A/metabolismo , Entamoeba/metabolismo , Entamoeba/fisiologia , Proteínas de Ligação ao GTP/metabolismo , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia de FluorescênciaRESUMO
Although Entamoeba dispar displays a similar morphology to Entamoeba histolytica, cellular and molecular studies have revealed significant differences between these two amoebae, including the former being characterized as non-pathogenic and the later as pathogenic. However, recent in vivo and in vitro experiments have shown that E. dispar strains of different origin are capable of causing liver damage and destroying cell culture lines in the presence of common intestinal bacteria. These results suggested that E. dispar may present pathogenic behavior according to the specific E. dispar strain, culture and environmental conditions. To investigate this possibility, we carried out in vivo and in vitro studies using a xenic strain E. dispar (ICB-ADO) isolated from a symptomatic non-dysenteric Brazilian patient. This strain was able to induce liver necrosis in a hamster model that was more severe than that produced by E. histolytica. The ICB-ADO isolate also caused significantly more destruction of cultured MDCK cells and increased loss of transepithelial resistance than did the E. histolytica. Xenic E. dispar exhibited high proteolytic activity, which was partially inhibited by the addition of cysteine-protease inhibitors. Based on our biochemical and molecular characterization of E. dispar (ICB-ADO) xenic culture and its ability to produce liver abscesses, we conclude that this specific strain can indeed produce tissue damage, distinct from the frequently used non- pathogenic E. dispar SAW 760 strain.
Assuntos
Entamoeba/classificação , Entamoeba/patogenicidade , Abscesso Hepático Amebiano/parasitologia , Fígado/parasitologia , Animais , Brasil , Células Cultivadas , Cricetinae , Modelos Animais de Doenças , Cães , Humanos , Técnicas In Vitro , Incidência , Rim/parasitologia , Rim/patologia , Fígado/patologia , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/patologia , Masculino , Mesocricetus , ProteóliseRESUMO
Food-borne parasitic diseases, many known to be more prevalent in poor countries with deficient sanitary conditions, are becoming common worldwide. Among the emerging protozoan parasites, the most prominent is Trypanosoma cruzi, rarely reported in the past to be transmitted by the oral route but currently responsible for frequent outbreaks of acute cases of Chagas disease contracted orally and characterized by high mortality. Several other food-borne protozoans considered emerging include the apicomplexans Toxoplasma gondii and Cryptosporidium, as well as Giardia and Entamoeba histolytica. Here, the interactions of these protozoans with the mucosal epithelia of the host are discussed.
Assuntos
Doenças Transmissíveis Emergentes/parasitologia , Doenças Transmitidas por Alimentos/parasitologia , Trypanosoma cruzi/patogenicidade , Apoptose , Adesão Celular , Doenças Transmissíveis Emergentes/transmissão , Cryptosporidium/patogenicidade , Entamoeba/patogenicidade , Interações Hospedeiro-Parasita , Humanos , Enteropatias Parasitárias/parasitologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/parasitologia , Mucinas/metabolismo , Infecções por Protozoários/parasitologia , Proteínas de Protozoários/metabolismo , Toxoplasma/patogenicidadeRESUMO
The influence of inflammation on the number of trophozoites and on the murine amoebic liver abscess area following infection with Entamoeba histolytica and E. dispar was evaluated. Immunohistochemistry and digital morphometry were used to identify and quantify the trophozoites, neutrophils, macrophages, and lesions. Positive correlation was observed between the number of trophozoites and inflammatory cells. A significant decrease in parasitism and inflammation in groups treated with dexamethasone was observed. The scarceness or absence of trophozoites in the treated groups suggest the importance of the inflammatory response in the production of amoebic hepatic abscesses in spite of the inherent virulence of the parasite being decisive in the establishment of the lesion.
Assuntos
Entamoeba/imunologia , Entamoeba/patogenicidade , Interações Hospedeiro-Parasita , Inflamação/patologia , Abscesso Hepático Amebiano/imunologia , Abscesso Hepático Amebiano/patologia , Fígado/patologia , Animais , Anti-Inflamatórios/administração & dosagem , Biometria , Dexametasona/administração & dosagem , Imuno-Histoquímica , Inflamação/imunologia , Fígado/parasitologia , Camundongos , MicroscopiaRESUMO
The human large intestine can harbor two morphologically similar amoebae; the invasive Entamoeba histolytica and the non-invasive Entamoeba dispar. Whereas E. histolytica can produce intestinal and extra-intestinal lesions, E. dispar is present in non-symptomatic carriers. Although biochemical, genetic and proteomic studies have identified clear differences between these Entamoebae, it has become clear that several molecules, once assumed to be involved in tissue destruction, exist in both the virulent and the avirulent species. As surface molecules may play a role in invasion and could therefore determine which amoebae are invasive, we analyzed the glycoconjugate composition of E. histolytica and E. dispar using lectins. There was a significant difference between E. histolytica and E. dispar in the expression of glycoconjugates containing d-mannose and N-acetyl-alpha-D-galactosamine residues, but not between virulent and avirulent strains of E. histolytica. N-glycoconjugates with terminal alpha (1-3)-linked mannose residues participate in the adhesion and subsequent cytotoxicity of E. histolytica to cultured hamster hepatocytes. One of them probably is the Gal/GalNAc lectin.
Assuntos
Entamoeba histolytica/metabolismo , Entamoeba/metabolismo , Glicoconjugados/metabolismo , Acetilgalactosamina/análise , Animais , Adesão Celular , Células Cultivadas , Cricetinae , Entamoeba/classificação , Entamoeba/crescimento & desenvolvimento , Entamoeba/patogenicidade , Entamoeba histolytica/crescimento & desenvolvimento , Entamoeba histolytica/patogenicidade , Entamebíase/parasitologia , Entamebíase/patologia , Glicoconjugados/química , Hepatócitos/parasitologia , Hepatócitos/patologia , Abscesso Hepático Amebiano/parasitologia , Abscesso Hepático Amebiano/patologia , Manose/análise , VirulênciaRESUMO
Evolution of experimental hepatic lesions produced in hamsters with Entamoeba histolytica and E. dispar was evaluated quantitatively and qualitatively through morphometry and immunohistochemistry. Animals infected with E. dispar developed hepatic lesions quantitatively and qualitatively similar to those produced by E. histolytica on the first three days of infection. On the 6th and 8th days of infection, E. histolytica produced larger tissue damage than E. dispar. A gradual decrease was observed in the number of trophozoites along the infection. A negative correlation was observed between the reduced number of trophozoites and the larger area of necrosis in both groups, confirming the importance of trophozoites killed in the lesion genesis. Regarding the genetic similarity between E. histolytica and E. dispar, comparison strategy between lesions produced by these species may culminate in identifying virulence factors of E. histolytica.
Assuntos
Cricetinae/parasitologia , Entamoeba histolytica/patogenicidade , Entamoeba/patogenicidade , Fígado/patologia , Fígado/parasitologia , Animais , Imuno-Histoquímica/veterinária , VirulênciaRESUMO
Two xenic isolates and cloned cultures of Entamoeba dispar were submitted to monoxenization using Crithidia fasciculata as the associated organism. Growth in monoxenic cultivation and ability of xenic and monoxenic trophozoites to destroy VERO cells and produce lesions in hamster livers were compared to those of a virulent E. histolytica. Parental and cloned E. dispar under monoxenic cultivation showed a remarkable lower growth than the monoxenic E. histolytica and were avirulent in both in vivo and in vitro tests. When xenically cultured, trophozoites of E. dispar showed a moderate lytic activity against VERO cells (1.5 to 41.8% of destruction) but caused severe hepatic lesions in hamsters as those caused by the virulent E. histolytica (29 to 100% in prevalence and 0.86 to 4.00 in lesion degree). Although E. dispar has not been associated with invasive disease in men, the ability of xenic trophozoites to produce prominent tissue damage in experimental conditions has indicated that some strains have a considerable pathogenic potential when in presence of bacteria.
Assuntos
Meios de Cultura , Entamoeba/patogenicidade , Fígado/parasitologia , Animais , Chlorocebus aethiops , Cricetinae , Crithidia fasciculata , Entamoeba/crescimento & desenvolvimento , Entamoeba histolytica/crescimento & desenvolvimento , Entamoeba histolytica/patogenicidade , Humanos , Fígado/patologia , Células Vero , VirulênciaRESUMO
Two xenic isolates and cloned cultures of Entamoeba dispar were submitted to monoxenization using Crithidia fasciculata as the associated organism. Growth in monoxenic cultivation and ability of xenic and monoxenic trophozoites to destroy VERO cells and produce lesions in hamster livers were compared to those of a virulent E. histolytica. Parental and cloned E. dispar under monoxenic cultivation showed a remarkable lower growth than the monoxenic E. histolytica and were avirulent in both in vivo and in vitro tests. When xenically cultured, trophozoites of E. dispar showed a moderate lytic activity against VERO cells (1.5 to 41.8 percent of destruction) but caused severe hepatic lesions in hamsters as those caused by the virulent E. histolytica (29 to 100 percent in prevalence and 0.86 to 4.00 in lesion degree). Although E. dispar has not been associated with invasive disease in men, the ability of xenic trophozoites to produce prominent tissue damage in experimental conditions has indicated that some strains have a considerable pathogenic potential when in presence of bacteria.
Dois isolados de Entamoeba dispar em cultivo polixênico e culturas clonadas deles obtidas foram submetidos à monoxenização utilizando Crithidia fasciculata como organismo associado. O crescimento em cultivo monoxênico dos isolados e clones, bem como sua capacidade de destruir células VERO (efeito citopático) e de produzir lesões hepáticas em hamster foram comparados a uma cepa virulenta de E. histolytica. Os trofozoítos de E. dispar em cultivo monoxênico apresentaram um crescimento nitidamente menor que o de E. histolytica e foram avirulentos tanto no teste in vivo quanto in vitro. Entretanto, isolados e clones de E. dispar em cultivo polixênico exibiram uma atividade lítica moderada sobre as células VERO (1,5 to 41,8 por cento de destruição) e causaram lesões hepáticas em hamster (29 a 100 por cento em prevalência e 0,86 a 4,00 no grau de lesão) tão extensas quanto aquelas causadas pela E. histolytica. Embora E. dispar não seja associada à doença invasiva no homem, a ocorrência de lesões teciduais significativas, causadas por trofozoítos em condições experimentais, indica que esta espécie pode apresentar potencial patogênico considerável quando em presença de bactérias intestinais.
Assuntos
Humanos , Animais , Cricetinae , Meios de Cultura , Entamoeba/patogenicidade , Fígado/parasitologia , Chlorocebus aethiops , Crithidia fasciculata , Entamoeba histolytica/crescimento & desenvolvimento , Entamoeba histolytica/patogenicidade , Entamoeba/crescimento & desenvolvimento , Fígado/patologia , Células Vero , VirulênciaRESUMO
Conocer la prevalencia y la distribución por edad y sexo de parasitosis intestinales producidas por Entamoeba histolytica, Blastocystis hominis Endolimax nana, en la población del Ambulatorio Militar "La Rosaleda" 2004. Estudio descriptivo transversal de prevalencia con análisis bivariado de 754 pacientes de diversas edades y sexo, que asistieron durante el año 2004 al Ambulatorio Militar "La Rosaleda". Se les realizó examen simple de heces y coloración rápida con lugol. Se estudiaron 754 pacientes, 402 femeninos y 352 masculino, con edades comprendidas entre 0-94 años. La prevalencia de las parasitosis intestinales fue de 17,37 por ciento, obteniendo la mayor tasa Blastocystis hominis. La prevalencia general de Blastocystis hominis fue 10,34 por ciento, Entamoeba histolytica 4,64 por ciento, siendo los grupos etarios más afectados de 3-10 años y 21-35 años, en ambas parasitosis y ambos sexos. En el caso de Endolimax nana la prevalencia fue 2,39 por ciento, siendo más frecuente en mujeres con edades entre 36-50 años. El área de influencia del Ambulatorio Militar "La Rosaleda" está constituida por comunidades que cuentan con adecuada provisión de servicios básicos (agua potable, disposición de aguas servidas). Llama la atención la alta prevalencia de estas parasitosis en la población, sobre todo en adultos jóvenes. De esta información se puede inferir que la vía de transmisión más probable es a través de alimentos contaminados. La investigación parasitológica de los establecimientos de comida rápida y ambulante de la zona puede servir de base para estudios posteriores.
Assuntos
Humanos , Masculino , Adulto , Feminino , Pré-Escolar , Criança , Blastocystis hominis/parasitologia , Endolimax/parasitologia , Entamoeba/patogenicidade , Enteropatias Parasitárias/parasitologia , Gastroenteropatias/etiologia , Higiene/educaçãoRESUMO
The objective of this work was to evaluate the frequency of Entamoeba histolytica/Entamoeba dispar intestinal infection in HIV+/AIDS subjects and their HIV- close relatives or sexual partners. Enteric parasites were investigated in stool samples by microscopic examination and E. histolytica and E. dispar were identified by PCR. We found by microscopic analysis in HIV+/AIDS group that the E. histolytica/E. dispar complex was present in 5.9% of the members, while in the HIV- group was 2.9%. With PCR we found that the E. histolytica prevalence was 25.3% in the HIV+/AIDS group and 18.5% in the HIV-group. The difference in the results obtained with the microscopic and PCR is due to the different sensibility of the procedures. Besides, we found patients who were infected with E. histolytica in both groups were asymptomatic cyst passers. Our results suggest that E. histolytica strains prevalent in the studied community appear to be of low pathogenic potential.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Entamoeba histolytica/isolamento & purificação , Entamebíase/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/parasitologia , Animais , Entamoeba/genética , Entamoeba/isolamento & purificação , Entamoeba/patogenicidade , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Entamebíase/complicações , Entamebíase/parasitologia , Família , Fezes/parasitologia , Infecções por HIV/complicações , Humanos , Enteropatias Parasitárias/complicações , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , México/epidemiologia , Reação em Cadeia da Polimerase , Prevalência , Parceiros SexuaisRESUMO
A strain of Entamoeba dispar was characterized by clinical diagnosis, serological and electrophoretical isoenzyme analysis and by the polymorphism of a 482 bp genomic fragment analysis. The pathogenesis and virulence of this strain was investigated considering the experimental infection in hamster livers in association with the original intestinal microbiota. Liver lesions were observed in hamsters experimentally infected with trophozoites from xenic cultures, but not from the monoxenic cultures. Moreover, clones obtained from re-isolated strain Wil1R1 showed a distinct biological behavior. In fact, animals inoculated with Wil1R1ClB3 showed an intense acute inflammatory reaction with destructive focal hepatic lesions. These lesions were characterized as amebic abscesses. The association between bacteria and ameba has been fairly well studied because it affects the pathogenicity of the amebas and has important therapeutic implications. In this study, we demonstrated that E. dispar in association with the original microbiota is able to produce lesions in hamster liver in spite of its having been considered to be non-pathogenic in the hamster model. Based on these results we suggest that diagnosis of amebiasis needs to be made with more care and that clinical and therapeutical procedures need to be revised.
Assuntos
Disenteria Amebiana/parasitologia , Entamoeba/patogenicidade , Abscesso Hepático Amebiano/parasitologia , Animais , Bactérias/isolamento & purificação , Bactérias/patogenicidade , Infecções Bacterianas/complicações , Brasil , Técnicas de Cocultura , Cricetinae , Crithidia fasciculata/patogenicidade , Disenteria Amebiana/microbiologia , Entamoeba/genética , Entamoeba/crescimento & desenvolvimento , Entamoeba/isolamento & purificação , Entamoeba/metabolismo , Fezes/parasitologia , Humanos , Fígado/microbiologia , Fígado/parasitologia , Fígado/patologia , Abscesso Hepático Amebiano/microbiologia , Abscesso Hepático Amebiano/patologia , Mesocricetus , Polimorfismo Genético , Infecções Protozoárias em Animais/complicações , VirulênciaRESUMO
Entamoeba histolytica is the pathogenic species of Entamoeba that causes amoebic dysentery and other invasive disease. The morphologically similar species, E. dispar, is non-pathogenic and accounts for about 90% of the previously estimated 500 million E. histolytica infections world-wide. Because of the recent redefinition of E. histolytica and E. dispar, and the limited number of drugs available to treat amoebiasis, a new approach to treatment of individuals carrying these parasites is necessary. A meeting of eminent scientists has recently agreed that on no account should prophylaxis against amoebiasis be given, and no treatment without symptoms should be administered. The expense of treating asymptomatic individuals, both monetary and at the risk of over-use of precious drugs, does not appear to be justified. It would seem wise that we preserve currently effective anti-amoebic drugs and avoid the development of drug-resistant E. histolytica.
Assuntos
Entamoeba/classificação , Entamebíase/parasitologia , Amebicidas/administração & dosagem , Amebicidas/uso terapêutico , Animais , Contraindicações , Reservatórios de Doenças , Entamoeba/patogenicidade , Entamoeba/fisiologia , Entamoeba histolytica/classificação , Entamoeba histolytica/patogenicidade , Entamoeba histolytica/fisiologia , Entamebíase/tratamento farmacológico , Entamebíase/epidemiologia , Entamebíase/transmissão , Entamebíase/veterinária , Fezes/parasitologia , Humanos , Mamíferos/parasitologia , Especificidade da Espécie , VirulênciaRESUMO
Como parte del programa de atención primaria de la salud (APS) del año 1996, y en virtud que no existían datos epidemiológicos referidos a enteroparásitos hallados en niños de 0 a 14 años, residentes en una zona rural del Partido de Carmen de Patagones, Provincia de Buenos Aires, es que se realizó el presente estudio epidemiológico descriptivo. Se estudiaron 210 niños a los que se les efectúo un estudio parasitoscópico seriado de materia fecal y mucus anal. Los resultados mostraron que el 60,5 por ciento de la población estudiada era portadora de algún parásito intestinal. El monoparasitismo hallado fue de 67 por ciento, mientras que 33 por ciento restante presentó entre 2 y 5 formas parasitarias. El espectro parasitario fue el siguiente: entamoeba coli 31,5 por ciento, giardia lamblia 24,7 por ciento; enterobius vermicularis 18 por ciento; hymenolepis nana 10,4 por ciento; blastocystis hominis 10,4 por ciento; 10,3 por ciento; chilomastix mesnili 2,5 por ciento; entamoeba hystolytica 0,9 por ciento y trichuris 0,5 por ciento. La distribución parasitaria en los distintos sectores estudiados fue en general homogénea excepto para H. nana la cual presentó una prevalencia más altas en zonas de riesgos con relación a la zona seca. Los resultados obtenidos fueron comunicados a las autoridades sanitarias correspondientes