Determinación de características asociadas al potencial patogénico de aislamientos de Acanthamoeba, obtenidos a partir de muestras de equipos de la Universidad de Costa Rica

Tesis (licenciatura en microbiología y química clínica)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí

Potentially pathogenic Acanthamoeba genotype T4 isolated from dental units and emergency combination showers

Background: Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. Objective: The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. Methods: Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. Findings: All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. Main conclusion: The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebaeUniversidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí

Potentially pathogenic Acanthamoeba genotype T4 isolated from dental units and emergency combination showers

BACKGROUND Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. OBJECTIVE The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. METHODS Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. FINDINGS All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. MAIN CONCLUSION The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae

Potentially pathogenic Acanthamoeba genotype T4 isolated from dental units and emergency combination showers

<div><p> BACKGROUND Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. OBJECTIVE The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. METHODS Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. FINDINGS All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. MAIN CONCLUSION The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae.</p></div

Isolation and Molecular Characterization of Acanthamoeba Strains from Dental Units in Costa Rica

Free-living amoebae are protozoa widely distributed in nature, which can be found in a variety of environments. Four genera are recognized as causal agents of infections in humans and animals: Acanthamoeba, Naegleria, Balam uthia, and Sappinia. In this study, the presence of Acanthamoeba in dental units was determined and the isolates obtained were molecularly character ized; osmotolerance and thermotolerance assays were also performed to evaluate multiplication under these conditions, frequently associated with pathogenicity. The morphological analysis and partial sequencing of the 18S rDNA gene revealed the presence of Acanthamoeba genotype T4 in 14% of the units sampled. Osmotolerance and thermotolerance tests were positive for more than 80% of the isolates. Up to date, this is the first study that reports the detection, identification, and genotyping of Acanthamoeba isolated from dental units in Costa Rica and even in Latin-America. Further assays to determine the potential pathogenicity of these Acanthamoeba isolates are underway.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí

Juvenile Chronic Myelogenous Leukemia. A Case Report

La leucemia Mieloide Crónica (LMC) es una neoplasia mieloproliferativa crónica, caracterizada por un gen de fusión t(9,22). El curso normal de la enfermedad consta de 3 fases: crónica, acelerada y blástica. En su gran mayoría los pacientes son diagnosticados en fase crónica y por un hallazgo incidental. Es común en pacientes mayores de 60 años, y poco frecuentes en niños y adolescentes, de ahí la importancia del reporte de este caso. Caso clínico: Paciente diagnosticado con LMC que progresó a fase acelerada, debido a falla terapéutica a primera línea de tratamiento con imatibinib y segunda línea con nilotinib. Dicha falla se justifica por poca adherencia al tratamiento. La importancia de este reporte recae en la baja incidencia de casos de LMC juvenil y las diferencias reportadas en la literatura en cuanto a una progresión clínica más agresiva.Chronic myeloid leukemia (CML) is a chronic myeloproliferative neoplasm, characterized by a fusion gene t(9,22). The normal course of the disease consists in 3 phases: chronic, accelerated and blastic. The vast majority of patients are diagnosed in the chronic phase by an incidental finding. It is common in patients older than 60 years, and infrequent in children and adolescents, hence the importance of this case report. Clinical case: Patient with a diagnosis of CML that progresses to an accelerated phase, due to therapeutic failure in the first line of treatment with imatibinib and second line with nilotinib. This failure is justified by poor adherence to treatment. This report is important due to the low incidence of cases of juvenile CML and the differences reported in the literature, since it has a more aggressive clinical progression than in adults.Caja Costarricense del Seguro Social/[]/CCSS/Costa RicaUniversidad de Costa Rica/[]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Hematología y Trastornos Afines (CIHATA