Parasitosis ocular por Acanthamoeba / Acanthamoeba parasitic eye infection

RESUMEN El parasitismo es uno de los fenómenos más sorprendentes de los observados en los animales. El número de organismos conocidos de vida parasitaria es muy elevado. Existe una gran cantidad de especies cuya supervivencia está relacionada con la de otras y dependen, en distinta medida, de ellas. Esta dependencia no implica que los animales parásitos sean organismos degenerados o deficientes; al contrario, a la vida parasitaria se ha llegado tras largo tiempo de evolución, en el que los parásitos han ido superando barreras y adaptándose a vivir en, o sobre sus hospedadores. Las queratitis por Acanthamoeba son infrecuentes; pero se describe un aumento a nivel mundial relacionado con el uso creciente de lentes de contacto. El diagnóstico precoz y el tratamiento adecuado deben realizarse para evitar la pérdida de la visión. Se realizó una búsqueda de artículos publicados, con el objetivo de conocer sobre la Acanthamoeba como parásito y su afectación ocular. Se utilizó la plataforma Infomed, específicamente la Biblioteca Virtual de Salud(AU)

ABSTRACT Parasitism is one of the most surprising phenomena among those occurring in animals. The number of known parasitic organisms is very high. There is a large number of species whose survival is related to that of others and depend on them to a greater or lesser degree. Such dependence does not imply that parasitic animals are either degenerate or deficient. On the contrary, parasitic life has been the result of a long process of evolution along which parasites have gradually overcome hurdles and have adapted to live in or on their hosts. Acanthamoeba keratitis is a rare disease, but a worldwide increase has been reported due to the growing use of contact lenses. Early diagnosis and appropriate treatment are required to prevent sight loss. A search was conducted for published papers with the purpose of learning about Acanthamoeba as a parasite and the related eye conditions. Use was made of the platform Infomed, specifically the Virtual Health Library(AU)

The first Acanthamoeba keratitis case in the Midwest region of Brazil: diagnosis, genotyping of the parasite and disease outcome

Abstract We report an Acanthamoeba keratitis case associated with the use of contact lens in a 28-year-old female from Brasília, Brazil. Samples from corneal scraping and contact lens case were used for culture establishment, PCR amplification, and partial sequencing (fragments of ~400kb) of small subunit rDNA; both culture and PCR were positive. The sequence analyses of the cornea and of isolates from the contact lens case showed similarity with the T4 genotype. To the best of our knowledge, this is the first report of T4 Acanthamoeba keratitis case from the Midwest region of Brazil.

Acanthamoeba spp: ecoepidemiología, biología, ultraestructura, patogénesis y diagnóstico en el hombre / Acanthamoeba: ecoepidemiology, biology, ultrastructure, pathogenesis and diagnosis in humans

En el presente trabajo presentamos nuestros estudios referidos al protozoo Acanthamoeba, desde lo morfológico, diagnóstico de laboratorio, patología en el ser humano, aspectos epidemiológicos y resistencia al cloro. Se aisló Acanthamoeba en el 28.6% de los tanques domiciliarios de agua, en el 71% de piscinas cubiertas, en la totalidad de las muestras del arroyo Napostá, que cruza la ciudad de Bahía Blanca, y no fue detectada en el agua de la red. Con referencia a la acción quisticida del cloro, se logró inhibir el crecimiento recién a las tres horas de exposición en 60 ppm de cloro. Realizamos el primer aislamiento de un paciente con queralitis, en Bahía Blanca. Hasta el momento no aislamos Acanthamoeba de otras muestras biológicas. Con referencia a los aspectos morfológicos, documentamos la ultraestructura de las cepas regionales de Acanthamoeba y realizamos la tipificación molecular de la cepa aislada del paciente con queralitis, una afección que, si bien es de baja prevalencia y su diagnóstico etiológico es de fácil ejecución y bajo costo, no justifica no realizar el estudio oportuna y rápidamente. La sensibilidad de la observación directa por microscopia óptica fue del 11.43%, comparada con los cultivos. Finalmente efectuamos un listado de recomendaciones para usuarios de lentes de contacto.

Examen histopatológico a lente de contacto paciente con queratitis por Acanthamoeba: informe preliminar / Histopathologic examination to contact lens in patient with keratitis by Acanthamoeba: preliminary report

Un grupo de amebas de vida libre (AVL) es capaz de producir afecciones graves en la especie humana, tales como Meningoencefalitis Amebiana Primaria; Encefalitis Granulomatosa Amebiana; y Queratitis por colonización del epitelio corneal en individuos inmunocompetentes, especialmente en usuarios permanentes de lentes de contacto. Se procede a efectuar estudio histológico a lente de contacto proveniente de paciente de 45 años, con diagnóstico presuntivo de queratitis por Acanthamoeba sp. Y cuya muestra de raspado de córnea resulto positivo en medio de cultivo ANNE. Las muestras fueron teñidas con PAS y observadas al microscopio con 4x, 10x y 40x, observándose estructuras altamente sugerentes de quistes de este grupo de amebas. Por la importancia que requiere obtener un diagnóstico rápido y certero en esta patología ocular, debido a que los métodos tradicionales demoran alrededor de una semana, consideramos relevante dar a conocer este hallazgo citohistológico.

The role of domestic tap water in Acanthamoeba contamination in contact lens storage cases in Korea

A survey was carried out from August to December 2004 in Pusan, Korea to document the presence of free-living amoeba (FLA), including the genus Acanthamoeba, in both contact lens storage cases and domestic tap water. Acanthamoeba was isolated from 5 (4.2%) in 120 contact lens storage cases. Four house tap water samples from residents, whose contact lens storage cases had been contaminated by Acanthamoeba, were also found to be contaminated with Acanthamoeba. Therefore, the contamination rate of FLA and Acanthamoeba in domestic tap water was investigated in order to examine the role of domestic tap water in Acanthamoeba contamination of contact lens storage cases. FLA and Acanthamoeba were identified in 97 (46.8%) and 16 (7.7%) of the 207 domestic tap water samples, respectively. There were no significant differences between the contamination rates of FLA in tap water according to the filtration plant of origin. No FLA was detected in the tap water directly supplied by the water purification plants. Water storage tanks appear to promote FLA colonization, including Acanthamoeba, in domestic tap water. This increases the risk of Acanthamoeba contamination in contact lens storage cases as well as increasing the risk of Acanthamoeba keratitis.

Genetic analyses of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea

We conducted both the small subunit ribosomal DNA (SSU rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and mitochondrial (mt) DNA RFLP analyses for a genetic characterization of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea. Twenty-three strains of Acanthamoeba from the American Type Culture Collection and twelve clinical isolates from Korean patients were used as reference strains. Thirty-nine isolates from contact lens storage cases were classified into seven types (KA/LS1, KA/LS2, KA/LS4, KA/LS5, KA/LS7, KA/LS18, KA/LS31). Four types (KA/LS1, KA/LS2, KA/LS5, KA/LS18) including 33 isolates were regarded as A. castellanii complex by riboprints. KA/LS1 type was the most predominant (51.3%) in the present survey area, followed by KA/LS2 (20.9%), and KA/LS5 (7.7%) types. Amoebae of KA/LS1 type had the same mtDNA RFLP and riboprint patterns as KA/E2 and KA/E12 strains, clinical isolates from Korean keratitis patients. Amoebae of KA/LS2 type had the identical mtDNA RFLP patterns with A. castellanii Ma strain, a corneal isolate from an American patient as amoebae of KA/LS5 type, with KA/E3 and KA/E8 strains from other Korean keratitis patients. Amoebae of KA/LS18 type had identical patterns with JAC/E1, an ocular isolate from a Japanese patient. Three types, which remain unidentified at species level, were not corresponded with any clinical isolate in their mtDNA RFLP and riboprint patterns. Out of 39 isolates analyzed in this study, mtDNA RFLP and riboprint patterns of 33 isolates (84.6%) were identical to already known clinical isolates, and therefore, they may be regarded as potentially keratopathogenic. These results suggest that contact lens wearers in Seoul should pay more attention to hygienic maintenance of contact lens storage cases for the prevention of Acanthamoeba keratitis.