Cromoforo fotoactivado con crosslinking como tratamiento para la queratitis por Acanthamoeba / Photoactivated chromophore with crosslinking as treatment for Acanthamoeba keratitis

RESUMEN Se reporta el uso del crosslinking como tratamiento de la queratitis por Acanthamoeba en una serie de 7 pacientes quienes acudieron al Servicio de Córnea por queratitis multitratadas. Se les realizó biopsia corneal, la cual se cultivó en solución de Page. Los pacientes fueron tratados con un protocolo de PACK-CXL durante más de 5 minutos y fueron sometidos a la exposición a la luz UV-A. El edema del nuevo epitelio era de 2 cruces a las 24 horas, y desapareció a las dos semanas del procedimiento en todos los casos. El porcentaje de desepitelización basal al momento del diagnóstico fue de 75,7 por ciento. La agudeza visual mejor corregida fue de entre 20/20 y 20/30. Se concluye que el uso de crosslinking en pacientes con Acanthamoeba en fases inicales pudiera ser una opción terapéutica segura y efectiva(AU)

ABSTRACT A report is presented of the use of crosslinking as treatment for Acanthamoeba keratitis in a series of 7 patients attending the Cornea Service for multitreated keratitis. Corneal biopsy was performed, which was cultured in Page solution. The patients were treated with a PACK-CXL protocol for more than 5 minutes and subjected to UV-A light exposure. Edema of the new epithelium was 2 crosses at 24 hours and disappeared 2 weeks after the procedure in all cases. Basal de-epithelialization percentage at diagnosis was 75.7 percent. Best corrected visual acuity ranged between 20/20 and 20/30. It is concluded that the use of crosslinking in patients with Acanthamoeba keratitis in its initial stages could be a safe and effective therapeutic option(AU)

Isolation and identification of Acanthamoeba spp. from thermal swimming pools and spas in Southern Brazil.

Free-living amoebae (FLA) are widely distributed in soil and water. A few number of them are implicated in human disease: Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris and Sappinia diploidea. Species of Acanthamoeba can cause keratitis and brain infections. In this study, 72 water samples were taken from both hot tubs and thermal swimming pools in the city of Porto Alegre, RS, Brazil, to determine the presence of Acanthamoeba in the water as well as perform the phenotypic and genotypic characterization of the isolates. The identification of the isolates was based on the cysts morphology and PCR amplification using genus-specific oligonucleotides. When the isolates were submitted to PCR reaction only 8 were confirmed as belonging to the genus Acanthamoeba. The sequences analysis when compared to the sequences in the GenBank, showed genotype distribution in group T3 (12,5%), T5 (12,5%), T4 (25%) and T15 (50%). The results of this study confirmed the presence of potentially pathogenic isolates of free living amoebae in hot swimming pool and spas which can present risks to human health.

Acanthamoeba royreba: morphological features and in vitro cytopathic effect.

Observations on cultured Acanthamoeba royreba trophozoites and in vitro cytopathogenicity of this amoeba are described. In culture, amoebae were active, pleomorphic and moved on the substrate by producing endocytic structures and emitting slight cytoplasmic microprojections from the cell surface. These projections were formed by hyaline cytoplasm and they were related to motion structures such as acanthopodia and lamellipodia, in which actin provides a framework that allows rapid changes in morphology. In the cytoplasm abundant vacuoles of different size and content were seen. By means of electron microscopy, it was possible to observe the compact fibrogranular appearance of the cytoplasm, along with the main cellular organelles such as the Golgi complex, the endoplasmic reticulum, digestive vacuoles, mitochondria and contractile vacuoles. Incubation of MDCK epithelial cell monolayers with conditioned medium did not produce a significant structural damage to the monolayer, even after 24h of incubation. When the trophozoites were incubated with the target cells the monolayer exhibited a clear injury created by the amoebae, which produced focal damage. Nevertheless, the rest of the monolayer appeared to remain intact, suggesting that a contact-dependent interaction is necessary to damage the target cells. These observations demonstrate the low invasive capacity of this amoeba.

Prevalence of Acanthamoeba spp. (Sarcomastigophora: Acanthamoebidae) in wild populations of Aedes aegypti (Diptera: Culicidae).

Studies of interrelationship between microorganisms and mosquitoes are of great importance, since it can provide support for better understand related to biology, development and their control. In this way, it is known that mosquito larvae and free-living amoebae (FLA) normally occupy similar aquatic microhabitats. However, few studies have been conducted about such coexistence. For that reason, the objective of the present study was to verify the prevalence of Acanthamoeba spp. in wild populations of Aedes aegypti, as well as to characterize the genotypic lineage, and their possible pathogenicity through thermo- and osmotolerance. Amoebae were investigated in 60 pools, each containing ten larvae of A. aegypti, collected in Porto Alegre (Rio Grande do Sul, Brazil). The Acanthamoeba isolates were morphologically characterized and submitted to the polymerase chain reaction technique to confirm identification of the genus. In addition, genotype analyses as well as tests for presumptive pathogenicity in some samples were performed. Of the 60 pools examined, 54 (90 %) were positive for FLA. Of these isolates, 47 (87 %) belonged to the genus Acanthamoeba. The genotypic groups T4, T3 and T5 were identified, numbering 14 (53.8 %), ten (38.5 %) and two (7.7 %) isolates, respectively. The physiological tests performed with 14 strains showed that 12 (85.7 %) were non-pathogenic, while two (14.3 %) were considered as having low pathogenic potential. These results provide a basis for a better understanding of the interaction between these protozoan and mosquitoes in their natural habitat. This study is the first to report the isolation of Acanthamoeba spp. from wild mosquitoes.

Characterization of acanthamoeba isolates from dust of a public hospital in Curitiba, Paraná, Brazil.

Occurrence of Acanthamoeba in the hospital environment may represent a health risk for patients, since these organisms can cause severe opportunistic illness, such as keratitis, and also can harbor pathogenic agents. We analyzed the dust from some environments of a public hospital in Curitiba, Parana State, Brazil. Two distinct populations of Acanthamoeba were isolated in five locations and morphologically classified as group I and group II according to Pussard and Pons. Isolates were identified as Acanthamoeba by PCR using primers to amplify a region of 18S rDNA, which showed variation in the product length among the isolates. A cloned culture of group II showed greater growth at 37 degrees C and in media with 0.1, 0.5, and 1.0 M mannitol, which are the physiological characteristics of pathogenic Acanthamoeba. Monitoring the presence of Acanthamoeba in hospital units, as well as evaluating the pathogenicity of the isolates, can be an approach to alert the health professionals to improve the disinfection procedures and minimize the risks of treating this problematic disease caused by this protozoan.

[Infections caused by free-living amebas. Historical commentaries, taxonomy and nomenclature, protozoology and clinicopathologic features]. / Infecciones por amebas de vida libre. Comentarios históricos, taxonomía y nomenclatura, protozoología y cuadros anátomo-clínicos.

Infections caused by free-living amebae constitute one of emergent opportunistic infections with greatest medical interest. Although infrequently, they have been described in almost all world, its diagnosis depends on a high index of suspicion, especially in morpho-pathologic and laboratory studies. Exciting historical features of infections due to free-living amebae, its taxonomy and the present nomenclature are briefly reviewed. An analysis of the protozoology of the most frequent agents is done and, based on the author's own experience and the published one, already established anatomo-clinical entities are described: the primary amebic meningoencephalitis, granulomatous amebic encephalitis, Acanthamoeba keratitis, cutaneous acanthamoebiasis, disseminated infection and other rare isolated locations.