RESUMO
Cryptococcus neoformans and Cryptococcus gattii are the main pathogenic species of invasive cryptococcosis among the Cryptococcus species. Taxonomic studies have shown that these two taxa have different genotypes or molecular types with biological and ecoepidemiological peculiarities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been proposed as an alternative method for labor-intensive methods for C. neoformans and C. gattii genotype differentiation. However, Vitek MS, one of the commercial MALDI-TOF MS instruments, has not been yet been evaluated for this purpose. Thus, we constructed an in-house database with reference strains belonging to the different C. neoformans (VNI, VNII, VNIII, and VNIV) and C. gattii (VGI, VGII, VGIII, and VGIV) major molecular types by using the software Saramis Premium (bioMérieux, Marcy-l'Etoile, France). Then, this new database was evaluated for discrimination of the different genotypes. Our in-house database provided correct identification for all C. neoformans and C. gattii genotypes; however, due to the intergenotypic mass spectral similarities, a careful postanalytic evaluation is necessary to provide correct genotype identification.
Assuntos
Criptococose/microbiologia , Cryptococcus gattii/genética , Cryptococcus neoformans/genética , Técnicas de Tipagem Micológica/métodos , Técnicas de Tipagem Micológica/normas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/normas , Cryptococcus gattii/química , Cryptococcus gattii/classificação , Cryptococcus gattii/isolamento & purificação , Cryptococcus neoformans/química , Cryptococcus neoformans/classificação , Cryptococcus neoformans/isolamento & purificação , Bases de Dados Genéticas , Genótipo , HumanosRESUMO
The VITEK 2 system was evaluated for the identification of 74 Trichosporon invasive and non-invasive clinical isolates, comparing its results with the IGS1 sequencing. The system correctly identified Trichosporon asahii but not non-T. asahii isolates, which represented nearly 50% of the invasive infections in our nosocomial setting.
Assuntos
Técnicas de Tipagem Micológica/métodos , Técnicas de Tipagem Micológica/normas , Trichosporon/classificação , Trichosporon/genética , Tricosporonose/microbiologia , DNA Fúngico/análise , DNA Fúngico/genética , Genótipo , Humanos , Filogenia , Reprodutibilidade dos Testes , Tricosporonose/diagnósticoRESUMO
Members of the Cryptococcus species complex are encapsulated basidiomycetous yeasts, which can affect the central nervous system (CNS) and if untreated may cause meningitis. Cryptococcus neoformans is an opportunistic pathogen causing infections mainly in immunocompromised individuals. Cryptococcus gattii is a primary pathogen responsible for a high incidence of cryptococcomas in the lung and brain and shows a delayed response to antifungal therapy. The differentiation between the two species is primarily based on their growth on and color change of canavanine - glycine-bromothymol blue agar (CGB). Since this test is not always reliable, a multiplex PCR to identify both Cryptococcus species using more than 130 samples was standardized and the results obtained compared to those with the CGB test, using the Crypto Check serotyping kit as the standard. The multiplex PCR was shown to be more specific than the CGB test, in that results obtained with it were in agreement with those from serotyping all the samples, while the data from the CGB test disagreed with 6 out of 131 samples.
Assuntos
Cryptococcus neoformans/classificação , Reação em Cadeia da Polimerase/métodos , DNA Fúngico/análise , Técnicas de Tipagem Micológica/métodos , Técnicas de Tipagem Micológica/normas , Polimorfismo de Fragmento de Restrição , Sensibilidade e Especificidade , Análise de Sequência de DNARESUMO
Se evaluó la capacidad de los laboratorios participantes del Sub Programa Micología para identificar diferentes cepas de hongos al nivel de género o especie. Tomados los resultados en conjunto, el 66% de los laboratorios identificó en forma correcta las cepas, mientras que otro 25% lo hizo en forma parcial. En el caso de los dermatofitos hubo un mayor porcentaje de respuestas correctas para el reconocimiento de Trichophyton mentagrophytes (76%) respecto de las especies de Microsporum evaluadas: M. canis (66%) y M. gypseum (65%). Los resultados de la identificación de las especies de levaduras mostraron dos grupos diferentes: uno conformado por Candida albicans y Cryptococcus neoformans, con elevados porcentajes de respuestas correctas (87 y 95%, respectivamente) y otro por C. tropicalis y C. glabrata, que ocasionó dificultades para su correcta identificación (sólo 28 y 32% de respuestas correctas). Las especies de Aspergillus evaluadas (A. fumigatus y A. niger) fueron reconocidas en forma correcta por el 63 y 72% de los participantes. Los resultados obtenidos, si bien son considerados como aceptables, evidencian la necesidad de mejorar la capacidad evaluada, teniendo en cuenta su influencia decisiva sobre la calidad del diagnóstico micológico.
The ability to identify different fungal strains at genera or specie level for participant laboratories of the Mycology Sub-Program, was evaluated. Taking into account all results as a whole, 66% of laboratories identified the strains correctly, while another 25% recognized the strains partially. Regarding dermatophytes, a higher percentage of correct responses for Trichophyton mentagrophytes recognition was observed with respect to (76%) those of the evaluated Microsporum species: M. canis (66%) and M. gypseum (65%). The results produced by the identification of yeasts species showed 2 different groups: one constituted by Candida albicans and Cryptococcus neoformans, with higher percentages of correct responses (87 and 95%, respectively) and another one constituted by C. tropicalis and C. glabrata, which presented difficulties for their correct identification (28 and 32% correct responses). The evaluated species of Aspergillus (A. fumigatus and A. niger) were recognized by 63% and 72% of the participants. The results obtained, considered as acceptable, show the need to improve the evaluated capacity, taking into account their decisive influence on mycologic diagnosis quality.
Assuntos
Micologia/normas , Micoses/diagnóstico , Controle de Qualidade , Controle de Qualidade , Técnicas de Tipagem Micológica/instrumentação , Técnicas de Tipagem Micológica/normas , Técnicas de Cultura/normasRESUMO
Two growth stages, conidia (C) and mycelium (M), and two media, minimal medium (MM) and complete medium (MC), were compared in 10 strains of "M. anisopliae", and two strains of "M. anisopliae" var. "majus" were similar in percentages of total lipids. Tukey test for average of lipid content in conidia (C) and mycelia (M) cultured on minimal (MM) and complete (MC) media showed significant differences between means at the 5(per cent) level of mycelia and conidia, indicating variability in total lipid production and storage during growth. Strains 5 and 7, both variety "majus", did not present sizable differences from variety "anisopliae". For fatty acids, C18:1 and C18:2, oleic and linoleic, respectively, the differences were all highly significant (p=1(per cent)) with highest means being obtained for conidia for fatty acid C18:1 and for mycelia for fatty acid C18:2.