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.

T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers. The determination of the pathogenic potential of Acanthamoeba clinical and environmental isolates using experimental models is extremely important to elucidate the capacity of free-living organisms to establish and cause disease in hosts. The aim of this study was to compare and evaluate the histopathology and culture between two different routes of experimental infection of T4 Acanthamoeba isolated from environmental and clinical source in mice (intracranial and intraperitoneal). Swiss isogenic healthy mice were inoculated with 10(4) trophozoites by intracranial (IC) and intraperitoneal (IP) routes and observed during 21 days. The brains from animals inoculated by the IC route were collected and from the animals of the IP inoculation group, the brains, livers, kidneys, spleens, and lungs were removed. The organs were prepared and appropriately divided to be evaluated with histopathology and culture. There was no significant difference between the inoculation routes in terms of isolates recovery (χ(2) = 0.09; p = 0.76). In the IC group, isolate recovery rate was significantly higher in histopathology than the one achieved by culture (χ(2) = 6.45; p < 0.01). Experimental infection revealed that all isolates inoculated could be considered invasive because it was possible to recover evolutive forms of Acanthamoeba in both routes. This work represents the first in vivo pathogenicity assay of primary isolation source in Central region of Brazil showing in vivo pathogenicity and hematogenous spread capacity of these protozoa, improving the knowledge on free-living amoebae isolates.

Members of the genus Acanthamoeba are of the most common protozoa that has been isolated from a variety of environment and affect immunocompromised individuals, causing granulomatous amoebic encephalitis and skin lesions. Acanthamoeba, in immunocompetent patients, may cause a keratitis related to corneal microtrauma. These free-living amoebas easily adapt to the host environment and wield metabolic pathways such as the energetic and respiratory ones in order to maintain viability for long periods. The energetic metabolism of cysts and trophozoites remains mostly unknown. There are a few reports on the energetic metabolism of these organisms as they are mitochondriate eukaryotes and some studies under aerobic conditions showing that Acanthamoeba hydrolyzes glucose into pyruvate via glycolysis. The aim of this study was to detect the energetic metabolic pathways with emphasis on anaerobic metabolism in trophozoites of three isolates of Acanthamoeba sp belonging to the T4 genotype. Two samples were collected in the environment and one was a clinical sample. The evaluation of these microorganisms proceeded as follows: rupture of trophozoites (7.5 × 10 parasites/ml) and biochemical analysis with high performance liquid chromatography and spectrophotometry. The anaerobic glycolysis was identified through the detection of glucose, pyruvate, and lactate. The protein catabolism was identified through the detection of fumarate, urea, and creatinine. The fatty acid oxidation was identified through the detection of acetate, beta-hydroxybutyrate, and propionate. The detected substances are the result of the consumption of energy reserves such as glycogen and lipids. The anaerobic glycolysis and protein catabolism pathways were observed in all three isolates: one clinical and two environmental. This study represents the first report of energetic pathways used by trophozoites from different isolates of the T4 genotype Acanthamoeba.

ResumoA síndrome do roubo da subclávia refere-se a uma desordem vascular na qual ocorre inversão do fluxo de sangue da artéria vertebral ipsilateral, decorrente de uma estenose proximal à sua origem, geralmente uma oclusão da artéria subclávia ou, mais raramente, do tronco braquiocefálico. É uma doença relativamente rara, relatada em aproximadamente 6% dos pacientes assintomáticos com sopros cervicais. O Doppler pulsado (PW) é útil na análise da artéria vertebral, registrando informações capazes de identificar a presença da Síndrome do Roubo da Subclávia. Com base nas alterações hemodinâmicas da artéria vertebral avaliadas pelo estudo com Doppler espectral, pode ser classificada nos tipos 1 (oculto), 2 (intermitente ou parcial) e 3 (completo). Com o advento da angioplastia transluminal percutânea e, em seguida, dos stents, muitos advogam essa combinação de procedimentos como o tratamento de escolha dos casos sintomático dessa síndrome. IntroduçãoA síndrome do roubo da subclávia refere-se a uma desordem vascular na qual ocorrem inversão do fluxo de sangue da artéria vertebral ipsilateral, distalmente a uma estenose, oclusão da artéria subclávia proximal ou, mais raramente, do tronco braquicefálico. A arterioesclerose é a principal causa de doença oclusiva envolvendo a artéria subclávia.1 O tabagismo está presente em 78% a 100% dos casos e a concomitância de doença arterial coronariana, em 27% a 65% dos casos.2 A localização mais comum das lesões ateroscleróticas que causam inversão de fluxo na vertebral está na porção proximal da artéria subclávia esquerda.

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