RESUMO
The plasma membrane is essential in the pathogenicity of several microorganisms. However, to date, there are few studies related to the plasma membrane proteins in Naegleria fowleri; this amoeba produces a fatal disease called primary amoebic meningoencephalitis. In the present study, we analyzed the electrophoretic pattern of the membrane proteins of N. fowleri and compared it with the nonpathogenic N. lovaniensis and N. gruberi. We detected a 23-kDa protein (Nf23) present at a higher level in N. fowleri than in the nonpathogenic amoebae. The mass spectrometry analysis showed that the Nf23 protein has a sequence of 229 amino acids that corresponds to a membrane protein. The mRNA level of nf23 was overexpressed 4-fold and 40,000-fold in N. fowleri compared with N. lovaniensis and N. gruberi, respectively. Moreover, we found a 5-fold overexpression of nf23 in N. fowleri trophozoites recovered from mouse brains compared with trophozoites axenically cultivated. In addition, the cytopathic effect on Madin-Darby Canine Kidney cells coincubated with N. fowleri diminished in the presence of antibodies against Nf23; nevertheless, the nonpathogenic amoebae did not produce damage to the monolayer cells. These results suggest that the plasma membrane protein Nf23 is probably involved in the virulence of N. fowleri.
Assuntos
Naegleria fowleri/metabolismo , Naegleria fowleri/patogenicidade , Naegleria/metabolismo , Naegleria/patogenicidade , Proteínas de Protozoários/metabolismo , Virulência/genética , Animais , Encéfalo/metabolismo , Encéfalo/parasitologia , Cães , Expressão Gênica , Células Madin Darby de Rim Canino , Camundongos , Naegleria fowleri/genética , Proteínas de Protozoários/genética , Análise de Sequência de ProteínaRESUMO
The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. Entamoeba histolytica, Naegleriafowleri and Acanthamoeba spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.
Assuntos
Acanthamoeba/patogenicidade , Entamoeba histolytica/patogenicidade , Células Epiteliais/parasitologia , Interações Hospedeiro-Parasita , Naegleria fowleri/patogenicidade , Infecções por Protozoários/parasitologia , Acanthamoeba/metabolismo , Animais , Entamoeba histolytica/metabolismo , Células Epiteliais/metabolismo , Humanos , Naegleria fowleri/metabolismo , Infecções por Protozoários/metabolismoRESUMO
Little is known about the prevalence of Balamuthia mandrillaris within the environment due to its difficult isolation, but once an axenic culture is established, it is relatively easy to maintain. As most of the time researchers are interested mainly in isolating B. mandrillaris from environmental samples, the flora that accompanies it becomes second in importance. Therefore, this study aimed to determine which potentially pathogenic free-living amoebae, in addition to B. mandrillaris, could be found co-inhabiting a source of natural thermal water called "Agua Caliente" (Mexico), where this amoeba has previously been detected twice by molecular methods. A third sampling from this same source was carried out to try to isolate B. mandrillaris and other free-living amoebae using 37 and 45⯰C as isolation temperatures. For PCR techniques, specific primers were used for B. mandrillaris, Naegleria fowleri, and Acanthamoeba species, plus a universal primer set for the eukaryotic 18S SSU rRNA gene for other isolated amoebae. PCR products were sequenced for final identification. 42 strains of the primary isolate were obtained, but only 34 could be kept in culture. Of them, 23 strains were identified as Naegleria lovaniensis, eight strains as Acanthamoeba jacobsi, two strains as Stenamoeba sp. and only one was identified as Vermamoeba vermiformis. The isolation of B. mandrillaris was once again not successful, but the presence of potentially pathogenic and nonpathogenic free-living amoebae is reported for the first time in this type of water in Mexico thanks to molecular methodology.
Assuntos
Amoeba/patogenicidade , Fontes Termais/parasitologia , Acanthamoeba/classificação , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Acanthamoeba/patogenicidade , Amoeba/classificação , Amoeba/genética , Amoeba/isolamento & purificação , Balamuthia mandrillaris/classificação , Balamuthia mandrillaris/genética , Balamuthia mandrillaris/isolamento & purificação , Balamuthia mandrillaris/patogenicidade , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , Genótipo , Fontes Termais/química , Concentração de Íons de Hidrogênio , México , Naegleria fowleri/classificação , Naegleria fowleri/genética , Naegleria fowleri/isolamento & purificação , Naegleria fowleri/patogenicidade , Filogenia , Reação em Cadeia da Polimerase , Espectrofotometria , TemperaturaRESUMO
Naegleria fowleri causes a fatal disease known as primary amoebic meningoencephalitis. This condition is characterized by an acute inflammation that originates from the free passage of peripheral blood cells to the central nervous system through the alteration of the blood-brain barrier. In this work, we established models of the infection in rats and in a primary culture of endothelial cells from rat brains with the aim of evaluating the activation and the alterations of these cells by N. fowleri. We proved that the rat develops the infection similar to the mouse model. We also found that amoebic cysteine proteases produced by the trophozoites and the conditioned medium induced cytopathic effect in the endothelial cells. In addition, N. fowleri can decrease the transendothelial electrical resistance by triggering the destabilization of the tight junction proteins claudin-5, occludin, and ZO-1 in a time-dependent manner. Furthermore, N. fowleri induced the expression of VCAM-1 and ICAM-1 and the production of IL-8, IL-1ß, TNF-α, and IL-6 as well as nitric oxide. We conclude that N. fowleri damaged the blood-brain barrier model by disrupting the intercellular junctions and induced the presence of inflammatory mediators by allowing the access of inflammatory cells to the olfactory bulbs.
Assuntos
Barreira Hematoencefálica/parasitologia , Infecções Protozoárias do Sistema Nervoso Central/metabolismo , Células Endoteliais/metabolismo , Naegleria fowleri/metabolismo , Naegleria fowleri/patogenicidade , Proteínas de Junções Íntimas/metabolismo , Animais , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Infecções Protozoárias do Sistema Nervoso Central/patologia , Claudina-5/metabolismo , Cisteína Proteases/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-1beta/metabolismo , Interleucina-8/metabolismo , Masculino , Meningoencefalite/parasitologia , Meningoencefalite/patologia , Camundongos , Mucosa/parasitologia , Mucosa/patologia , Ocludina/metabolismo , Ratos , Ratos Wistar , Trofozoítos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Conchas Nasais/patologia , Molécula 1 de Adesão de Célula Vascular/metabolismo , Proteína da Zônula de Oclusão-1/metabolismoRESUMO
AIM: The aim of this work was to identify, characterize and evaluate the pathogenic role of mucinolytic activity released by Naegleria fowleri. MATERIALS & METHODS: Zymograms, protease inhibitors, anion exchange chromatography, MALDI-TOF-MS, enzymatic assays, Western blot, and confocal microscopy were used to identify and characterize a secreted mucinase; inhibition assays using antibodies, dot-blots and mouse survival tests were used to evaluate the mucinase as a virulence factor. RESULTS: A 94-kDa protein with mucinolytic activity was inducible and abolished by p-hydroxymercuribenzoate. MALDI-TOF-MS identified a glycoside hydrolase. Specific antibodies against N. fowleri-glycoside hydrolase inhibit cellular damage and MUC5AC degradation, and delay mouse mortality. CONCLUSION: Our findings suggest that secretory products from N. fowleri play an important role in mucus degradation during the invasion process.
Assuntos
Glicosídeo Hidrolases/metabolismo , Mucinas/metabolismo , Naegleria fowleri/enzimologia , Fatores de Virulência/metabolismo , Animais , Western Blotting , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/efeitos dos fármacos , Humanos , Hidroximercuribenzoatos/farmacologia , Camundongos , Microscopia Confocal , Naegleria fowleri/efeitos dos fármacos , Naegleria fowleri/metabolismo , Naegleria fowleri/patogenicidade , Polissacarídeo-Liases/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Naegleria fowleri causes acute and fulminant primary amoebic meningoencephalitis. This microorganism invades its host by penetrating the olfactory mucosa and then traveling up the mesaxonal spaces and crossing the cribriform plate; finally, the trophozoites invade the olfactory bulbs. During its invasion, the protozoan obtains nutrients such as proteins, lipids, carbohydrates, and cationic ions (e.g., iron, calcium, and sodium) from the host. However, the mechanism by which these ions are obtained, particularly iron, is poorly understood. In the present study, we evaluated the ability of N. fowleri to degrade iron-binding proteins, including hololactoferrin, transferrin, ferritin, and hemoglobin. Zymography assays were performed for each substrate under physiological conditions (pH 7 at 37°C) employing conditioned medium (CM) and total crude extracts (TCEs) of N. fowleri. Different degradation patterns with CM were observed for hololactoferrin, transferrin, and hemoglobin; however, CM did not cause ferritin degradation. In contrast, the TCEs degraded only hololactoferrin and transferrin. Inhibition assays revealed that cysteine proteases were involved in this process. Based on these results, we suggest that CM and TCEs of N. fowleri degrade iron-binding proteins by employing cysteine proteases, which enables the parasite to obtain iron to survive while invading the central nervous system.
Assuntos
Infecções Protozoárias do Sistema Nervoso Central/metabolismo , Cisteína Proteases/metabolismo , Interações Hospedeiro-Patógeno , Ferro/metabolismo , Proteólise , Animais , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Infecções Protozoárias do Sistema Nervoso Central/patologia , Proteínas de Ligação ao Ferro/metabolismo , Lactoferrina/metabolismo , Naegleria fowleri/enzimologia , Naegleria fowleri/patogenicidade , Bulbo Olfatório/metabolismo , Bulbo Olfatório/patologia , Transferrina/metabolismo , Trofozoítos/metabolismoRESUMO
In 2008 a fatal case of primary amoebic meningoencephalitis, due to the amoeboflagellate Naegleria fowleri, occurred in Guadeloupe, French West Indies, after a child swam in a bath fed with geothermal water. In order to improve the knowledge on free-living amoebae in this tropical part of France, we investigated on a monthly basis, the presence of Naegleria spp. in the recreational baths, and stream waters which feed them. A total of 73 water samples, 48 sediments and 54 swabs samples were collected from 6 sampling points between June 2011 and July 2012. The water samples were filtered and the filters transferred to non-nutrient agar plates seeded with a heat-killed suspension of Escherichia coli while sediment and swab samples were placed directly on these plates. The plates were incubated at 44°C for the selective isolation of thermophilic Naegleria. To identify the Naegleria isolates the internal transcribed spacers, including the 5.8S rDNA, were amplified by polymerase chain reaction and the sequence of the PCR products was determined. Thermophilic amoebae were present at nearly all collection sites. The pathogenic N. fowleri was the most frequently encountered thermophilic species followed by N. lovaniensis. The concentration of N. fowleri was rather low in most water samples, ranging from 0 to 22 per liter. Sequencing revealed that all N. fowleri isolates belonged to a common Euro-American genotype, the same as detected in the human case in Guadeloupe. These investigations need to be continued in order to counsel the health authorities about prevention measures, because these recreational thermal baths are used daily by local people and tourists.
Assuntos
Amebíase/microbiologia , Infecções Protozoárias do Sistema Nervoso Central/microbiologia , Fontes Termais/microbiologia , Naegleria fowleri/isolamento & purificação , Amebíase/epidemiologia , Infecções Protozoárias do Sistema Nervoso Central/epidemiologia , Criança , DNA Ribossômico/genética , Genótipo , Guadalupe , Humanos , Naegleria fowleri/patogenicidadeRESUMO
Naegleria fowleri is the aetiological agent of primary amoebic meningoencephalitis. This parasite invades its host by penetrating the olfactory mucosa. However, the mechanism of epithelium penetration is not well understood. In the present study, we evaluated the effect of N. fowleri trophozoites and the non-pathogenic Naegleria gruberi on Madin-Darby canine kidney (MDCK) tight junction proteins, including claudin-1, occludin and ZO-1, as well as on the actin cytoskeleton. Trophozoites from each of the free-living amoeba species were co-cultured with MDCK cells in a 1â:â1 ratio for 1, 3, 6 or 10 h. Light microscopy revealed that N. fowleri caused morphological changes as early as 3 h post-infection in an epithelial MDCK monolayer. Confocal microscopy analysis revealed that after 10 h of co-culture, N. fowleri trophozoites induced epithelial cell damage, which was characterized by changes in the actin apical ring and disruption of the ZO-1 and claudin-1 proteins but not occludin. Western blot assays revealed gradual degradation of ZO-1 and claudin-1 as early as 3 h post-infection. Likewise, there was a drop in transepithelial electrical resistance that resulted in increased epithelial permeability and facilitated the invasion of N. fowleri trophozoites by a paracellular route. In contrast, N. gruberi did not induce alterations in MDCK cells even at 10 h post-infection. Based on these results, we suggest that N. fowleri trophozoites disrupt epithelial monolayers, which could enable their penetration of the olfactory epithelium and subsequent invasion of the central nervous system.
Assuntos
Naegleria fowleri/patogenicidade , Proteínas de Junções Íntimas/metabolismo , Junções Íntimas/microbiologia , Actinas/metabolismo , Animais , Western Blotting , Técnicas de Cocultura , Cães , Células Madin Darby de Rim Canino , MicroscopiaRESUMO
A partir de 4 localidades donde se aislaron amebas del género Naegleria fowleri en Santiago de Cuba, se realizaron las técnicas necesarias para su adecuado estudio a través del microscopio electrónico de barrido. Con anterioridad, esas amebas fueron inoculadas en biomodelos experimentales (ratones), lo cual permitió determinar un nivel de patogenicidad diferente; y esto último, como es un aspecto controvertido en diversas teorías sobre sus causas (algunas analizadas aquí), entre las que se incluye la sustentada en la invaginación de su superficie (amebostomas o suctores), la autora de este trabajo se dio a la tarea de valorar la presencia (número y características) de los amebostomas o su ausencia a través del mencionado aparato, de donde se derivó que los ameboflagelados no patógenos apenas se diferenciaban de los que sí lo eran. Tal hallazgo pudo ser reafirmado cuando estos se compararon con 2 cepas reconocidas en el Instituto de Medicina Tropical de Checoslovaquia; por consiguiente, ese resultado descarta la citada causa en la patogenicidad de las amebas.
Taking into account 4 localities where amebas of the genus Naegleria fowleri were isolated in Santiago de Cuba, necessary techniques for their adequate study using the scanning electron microscope were performed. Previously, those amebas were inoculated in experimental biomodels (mice), which allowed to determine a different level of pathogenicity, a controversial issue in several theories about their causes (some discussed here), including that maintained in their surface invagination (amebostomas or suckers). Thus, the author of this work evaluated the presence (number and characteristics) or absence of amebostomas through such device, and it is concluded that pathogenic ameboflagellates were similar to those that were not. This finding could be confirmed when they were compared with 2 strains recognized in the Institute of Tropical Medicine of Czechoslovakia. Consequently, that result rules out the above cause in the pathogenesis of amebas.
Assuntos
Humanos , Amebíase , Microscopia Eletrônica de Varredura , Naegleria fowleri/patogenicidade , Naegleria/patogenicidadeRESUMO
Naegleria fowleri is the aetiological agent of primary amoebic meningoencephalitis (PAM). This parasite invades its host by penetrating the olfactory mucosa. During the initial stages of infection, the host response is initiated by the secretion of mucus that traps the trophozoites. Despite this response, some trophozoites are able to reach, adhere to and penetrate the epithelium. In the present work, we evaluated the effect of mucins on amoebic adherence and cytotoxicity to Madin-Darby canine kidney (MDCK) cells and the MUC5AC-inducing cell line NCI-H292. We showed that mucins inhibited the adhesion of amoebae to both cell lines; however, this inhibition was overcome in a time-dependent manner. N. fowleri re-established the capacity to adhere faster than N. gruberi. Moreover, mucins reduced the cytotoxicity to target cells and the progression of the illness in mice. In addition, we demonstrated mucinolytic activity in both Naegleria strains and identified a 37 kDa protein with mucinolytic activity. The activity of this protein was inhibited by cysteine protease inhibitors. Based on these results, we suggest that mucus, including its major mucin component, may act as an effective protective barrier that prevents most cases of PAM; however, when the number of amoebae is sufficient to overwhelm the innate immune response, the parasites may evade the mucus by degrading mucins via a proteolytic mechanism.
Assuntos
Amebíase/imunologia , Mucinas/farmacologia , Naegleria fowleri/patogenicidade , Polissacarídeo-Liases/metabolismo , Amebíase/parasitologia , Animais , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Cães , Humanos , Rim/citologia , Rim/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mucina-5AC/metabolismo , Mucinas/imunologia , Mucinas/toxicidade , Naegleria fowleri/crescimento & desenvolvimento , Naegleria fowleri/metabolismo , Proteínas de Protozoários/metabolismoRESUMO
Naegleria fowleri is a free-living amoeba and the etiologic agent of primary amoebic meningoencephalitis (PAM). Trophozoites reach the brain by penetrating the olfactory epithelium, and invasion of the olfactory bulbs results in an intense inflammatory reaction. The contribution of the inflammatory response to brain damage in experimental PAM has not been delineated. Using both optical and electron microscopy, we analyzed the morphologic changes in the brain parenchyma due to inflammation during experimental PAM. Several N. fowleri trophozoites were observed in the olfactory bulbs 72 h post-inoculation, and the number of amoebae increased rapidly over the next 24 h. Eosinophils and neutrophils surrounding the amoebae were then noted at later times during infection. Electron microscopic examination of the increased numbers of neutrophils and the interactions with trophozoites indicated an active attempt to eliminate the amoebae. The extent of inflammation increased over time, with a predominant neutrophil response indicating important signs of damage and necrosis of the parenchyma. These data suggest a probable role of inflammation in tissue damage. To test the former hypothesis, we used CD38-/- knockout mice with deficiencies in chemotaxis to compare the rate of mortality with the parental strain, C57BL/6J. The results showed that inflammation and mortality were delayed in the knockout mice. Based on these results, we suggest that the host inflammatory response and polymorphonuclear cell lysis contribute to a great extent to the central nervous system tissue damage.
Assuntos
Amebíase , Encéfalo , Inflamação , Meningoencefalite , Naegleria fowleri/patogenicidade , ADP-Ribosil Ciclase 1/genética , Amebíase/imunologia , Amebíase/mortalidade , Amebíase/parasitologia , Amebíase/fisiopatologia , Animais , Encéfalo/imunologia , Encéfalo/fisiopatologia , Encéfalo/ultraestrutura , Infecções Protozoárias do Sistema Nervoso Central/imunologia , Infecções Protozoárias do Sistema Nervoso Central/mortalidade , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Infecções Protozoárias do Sistema Nervoso Central/fisiopatologia , Humanos , Inflamação/imunologia , Inflamação/mortalidade , Inflamação/parasitologia , Inflamação/fisiopatologia , Masculino , Meningoencefalite/imunologia , Meningoencefalite/mortalidade , Meningoencefalite/parasitologia , Meningoencefalite/fisiopatologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Eletrônica de TransmissãoRESUMO
The initial stages of Naegleria fowleri meningoencephalitis in mice were immunohistochemically characterized following the first 8 h post-intranasal inoculation. The events found after 8 h were: (1) amebas in contact with the mucous layer of the olfactory epithelium, (2) numerous parasites eliminated by extensive shedding of the mucous layer, and (3) many organisms reaching the nasal epithelium. In contrast to other works, we observed that after 24 h, amebas invaded the epithelium, without evidence of the disruption of the nasal mucosa. In addition some trophozoites invading through the respiratory epithelium were observed, suggesting an additional invasion route. The inflammatory response detected was scarce until 30 h post-inoculation. After 96 h, the inflammatory response was severe in the olfactory bulb and brain, and the tissue damage great. Consequently, an inflammatory reaction may enhance tissue damage but apparently does not destroy amebas which seem to proliferate in the olfactory bulb.
Assuntos
Amebíase/fisiopatologia , Amebíase/parasitologia , Meningoencefalite/fisiopatologia , Meningoencefalite/parasitologia , Naegleria fowleri/patogenicidade , Amebíase/imunologia , Animais , Encéfalo/imunologia , Encéfalo/parasitologia , Encéfalo/patologia , Imuno-Histoquímica , Inflamação/imunologia , Inflamação/parasitologia , Inflamação/fisiopatologia , Masculino , Meningoencefalite/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Naegleria fowleri/crescimento & desenvolvimento , Bulbo Olfatório/imunologia , Bulbo Olfatório/parasitologia , Bulbo Olfatório/patologia , VirulênciaRESUMO
Cry1Ac protoxin has potent mucosal and systemic adjuvant effects on antibody responses to proteins or polysaccharides. In this work, we examined whether Cry1Ac increased protective immunity against fatal Naegleria fowleri infection in mice, which resembles human primary amoebic meningoencephalitis. Higher immunoglobulin G (IgG) than IgA anti-N. fowleri responses were elicited in the serum and tracheopulmonary fluids of mice immunized by the intranasal or intraperitoneal route with N. fowleri lysates either alone or with Cry1Ac or cholera toxin. Superior protection against a lethal challenge with 5 x 10(4) live N. fowleri trophozoites was achieved for immunization by the intranasal route. Intranasal immunization of N. fowleri lysates coadministered with Cry1Ac increased survival to 100%; interestingly, immunization with Cry1Ac alone conferred similar protection to that achieved with amoebal lysates alone (60%). When mice intranasally immunized with Cry1Ac plus lysates were challenged with amoebae, both IgG and IgA mucosal responses were rapidly increased, but only the increased IgG response persisted until day 60 in surviving mice. The brief rise in the level of specific mucosal IgA does not exclude the role that this isotype may play in the early defense against this parasite, since higher IgA responses were detected in nasal fluids of mice intranasally immunized with lysates plus either Cry1Ac or cholera toxin, which, indeed, were the treatments that provided the major protection levels. In contrast, serum antibody responses do not seem to be related to the protection level achieved. Both acquired and innate immune systems seem to play a role in host defense against N. fowleri infection, but further studies are required to elucidate the mechanisms involved in protective effects conferred by Cry1Ac, which may be a valuable tool to improve mucosal vaccines.
Assuntos
Amebíase/prevenção & controle , Proteínas de Bactérias/imunologia , Toxinas Bacterianas/imunologia , Endotoxinas/imunologia , Meningoencefalite/prevenção & controle , Naegleria fowleri/imunologia , Precursores de Proteínas/imunologia , Adjuvantes Imunológicos , Administração Intranasal , Amebíase/mortalidade , Amebíase/parasitologia , Animais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/metabolismo , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/administração & dosagem , Proteínas de Bactérias/genética , Toxinas Bacterianas/administração & dosagem , Toxinas Bacterianas/genética , Líquidos Corporais/imunologia , Endotoxinas/administração & dosagem , Endotoxinas/genética , Proteínas Hemolisinas , Humanos , Imunização , Pulmão/imunologia , Meningoencefalite/mortalidade , Meningoencefalite/parasitologia , Camundongos , Naegleria fowleri/patogenicidade , Mucosa Nasal/imunologia , Precursores de Proteínas/administração & dosagem , Traqueia/imunologiaRESUMO
Introducción. Las amibas de vida libre habitualmente viven como fagótrofas en el agua y suelo donde se alimentan de bacterias; también pueden producir infecciones del sistema nervioso central y otros tejidos en seres humanos y animales. La anemia aplástica es una entidad caracterizada por pancitopenia secundaria a disminución de la producción en médula ósea de todos los elementos formes de la sangre y ausencia de enfermedad primaria que infiltre, reemplace o anule la hematopoyesis activa. Casos clínicos. Se presentan 2 niños con historia de sangrados, pancitopenia y el diagnóstico de anemia aplástica grave por biopsia y aspirado de médula ósea, que finalmente fallecieron. Se muestran los hallazgos de amibas de vida libre en la médula. Conclusión. En estos casos no se encontró agente causal de la anemia aplástica, y se sugiere a las amibas como oportunistas del padecimiento.
Assuntos
Humanos , Masculino , Lactente , Criança , Acanthamoeba/patogenicidade , Amebíase , Anemia Aplástica/imunologia , Naegleria fowleri/patogenicidade , Pancitopenia/complicações , Infecções do Sistema Nervoso Central/microbiologia , Infecções Oportunistas/diagnósticoRESUMO
El objetivo es informar la ocurrencia de siete casos de meningoencefalitis por amiba de vida libre en población derechohabiente del Instituto Mexicano del Seguro Social en Mexicali, Baja California, entre 1990 y 1991. Se efectuó un estudio descriptivo y retrospectivo de los casos; se describen los principales signos y síntomas del padecimiento, así como los datos de laboratorio en líquido cefalorraquídeo y tratamiento. Todos los pacientes fallecieron. Se puede concluir que bañarse o nadar en canales de riego del municipio de mexicali, constituye un riesgo de enfermar y morir por amiba de vida libre. Se enfatiza la necesidad de aplicar medidas de educación para la salud entre la población en riesgo, así como establecer un diagnóstico oportuno y protocolizar el tratamiento curativo
Assuntos
Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Humanos , Masculino , Rifampina/uso terapêutico , Dexametasona/uso terapêutico , Anfotericina B/uso terapêutico , Naegleria fowleri/patogenicidade , Amebíase/prevenção & controle , Cetoconazol/uso terapêutico , Meningite/diagnósticoRESUMO
Las pequeñas amebas de vida libre están ampliamente distribuidas en todo el mundo en continuo contacto con el hombre y animales; sus formas quísticas son capaces de sobrevivir en el suelo, aire y agua. Las infecciones causadas por las mismas han tomado en los últimos treinta años notable importancia médica ya que muchos casos fatales no fueron diagnosticados clínicamente ni por el laboratorio, debido al desconocimiento de la potencial capacidad patogénica de estas amebas. Hoy se sabe que la meningoencefalitis amebiana primaria (MAP) causada por Naegleria fowleri y la encefalitits amebiana granulomatosa (EAG) originada por especies de Acanthamoeba spp se han incrementado en el mundo tanto en sujetos sanos como en inmunocomprometidos, incluyendo muchos individuos con SIDA. El grupo más reciente de infecciones causadas por especies del género Acanthamoeba es la queratitis amebiana relacionada principalmente con la falta de cuidado en el mantenimiento de las lentes de contacto. La terapia de la queratitis es problemática debido a la presencia de quistes en los tejidos, y aunque se han informado algunas curas de pacientes, la terapéutica médica aún constituye un capítulo no resuelto
Assuntos
Ceratite por Acanthamoeba/diagnóstico , Amebíase/diagnóstico , Amoeba/classificação , Meningoencefalite/etiologia , Ceratite por Acanthamoeba/etiologia , Ceratite por Acanthamoeba/microbiologia , Acanthamoeba/classificação , Acanthamoeba/crescimento & desenvolvimento , Amebíase/complicações , Amebíase/epidemiologia , Amoeba/isolamento & purificação , Amoeba/patogenicidade , Modelos Animais de Doenças , Meningoencefalite/microbiologia , Naegleria fowleri/crescimento & desenvolvimento , Naegleria fowleri/patogenicidade , Naegleria/classificação , Naegleria/crescimento & desenvolvimento , Naegleria/patogenicidadeRESUMO
Las pequeñas amebas de vida libre están ampliamente distribuidas en todo el mundo en continuo contacto con el hombre y animales; sus formas quísticas son capaces de sobrevivir en el suelo, aire y agua. Las infecciones causadas por las mismas han tomado en los últimos treinta años notable importancia médica ya que muchos casos fatales no fueron diagnosticados clínicamente ni por el laboratorio, debido al desconocimiento de la potencial capacidad patogénica de estas amebas. Hoy se sabe que la meningoencefalitis amebiana primaria (MAP) causada por Naegleria fowleri y la encefalitits amebiana granulomatosa (EAG) originada por especies de Acanthamoeba spp se han incrementado en el mundo tanto en sujetos sanos como en inmunocomprometidos, incluyendo muchos individuos con SIDA. El grupo más reciente de infecciones causadas por especies del género Acanthamoeba es la queratitis amebiana relacionada principalmente con la falta de cuidado en el mantenimiento de las lentes de contacto. La terapia de la queratitis es problemática debido a la presencia de quistes en los tejidos, y aunque se han informado algunas curas de pacientes, la terapéutica médica aún constituye un capítulo no resuelto (AU)
Assuntos
Amoeba/classificação , Amebíase/diagnóstico , Meningoencefalite/etiologia , Ceratite por Acanthamoeba/diagnóstico , Amoeba/isolamento & purificação , Amoeba/patogenicidade , Modelos Animais de Doenças , Ceratite por Acanthamoeba/etiologia , Ceratite por Acanthamoeba/microbiologia , Amebíase/complicações , Amebíase/epidemiologia , Meningoencefalite/microbiologia , Naegleria fowleri/crescimento & desenvolvimento , Naegleria fowleri/patogenicidade , Naegleria/classificação , Naegleria/crescimento & desenvolvimento , Naegleria/patogenicidade , Acanthamoeba/classificação , Acanthamoeba/crescimento & desenvolvimentoRESUMO
Five Naegleria strains isolated from patients with primary amebic meningoencephalitis and one strain isolated from the water of an artificial canal were investigated. All strains were pathogenic for mice when instilled intranasally and showed cytopathic effects in Vero cell cultures. Their growth characteristics (isolation and subculture at 45 degrees C), serological results, and isoenzyme patterns permitted us to identify the six strains as Naegleria fowleri. This is the first time that Naegleria fowleri has been isolated from patients with primary amebic meningoencephalitis in Mexico.