Compêndio de métodos e de boas práticas em coleção de cultura de leveduras do Instituto de Biologia do Exército / Compendium of methods and good practices in yeast culture collection of the Brazilian Army Biology Institute

Objetivo: O Compêndio de Métodos e de Boas Práticas em Coleção de Cultura de Leveduras do Instituto de Biologia do Exército (IBEx) foi elaborado com o propósito de operacionalizar as atividades de pesquisa, garantindo o desempenho seguro e confiável dos seus objetivos regimentais. Métodos: A Coleção de Cultura de Leveduras do IBEx foi criada a partir de cepas isoladas de quadros de candidíase sistêmica, através da utilização de metodologias manuais e automatizadas para autenticação das mesmas, com o propósito de garantir a pesquisa científica e atividades de ensino. Resultados: O Instituto adequou e modernizou seus laboratórios de pesquisa criando o Centro de Estudos em Biodefesa, com Nível de Biossegurança NB-3. Com base na necessidade de organização para atender às demandas da defesa biológica, o IBEx vem aprimorando sua estrutura para dominar e garantir novas tecnologias de identificação e manejo dos microrganismos envolvidos em Bioterrorismo. Conclusão: A compilação de metodologias na forma de um Compêndio proporcionou a operacionalização da Coleção de Cultura do IBEx.

Objective: The Compendium of Methods and Good Practices in Yeast Culture Collection of the Brazilian Army Biology Institute (IBEx) was elaborated with the purpose of operationalizing the research activities, guaranteeing the safe and reliable performance of its regimental objectives. Methods: The IBEx Yeast Culture Collection was created from isolated strains of systemic candidiasis, through the use of manual and automated methodologies to authenticate them, in order to guarantee scientific research and teaching activities. Results: The Institute adapted and modernized its research laboratories by creating the Center for Biodefense Studies, with Biosafety Level NB-3. Based on the need for organization to meet the demands of biological defense, the IBEx has been improving its structure to dominate and guarantee new technologies of identification and management of the microorganisms involved in Bioterrorism. Conclusion: The compilation of methodologies in the form of a Compendium provided the operationalization of the IBEx Culture Collection

Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth.

We assessed fluconazole susceptibility in 52 Candida tropicalis clinical strains using seven antifungal susceptibility methods, including broth microdilution (BMD) [standard M27 A3 (with neutral and acid pH), ATB Fungus 3, Vitek 2 system and flow cytometric analysis] and agar-based methods (disk diffusion and E-test). Trailing growth, detection of cell-associated secreted aspartic proteases (Saps) and morphological and ultrastructural traits of these clinical strains were also examined. The ranges of fluconazole 24 h-minimum inhibitory concentration (MIC) values were similar among all methods. The essential agreement among the methods used for MIC determinations was excellent and all methods categorised all strains as susceptible, except for one strain that showed a minor error. The presence of the trailing effect was assessed by six methods. Trailing positivity was observed for 86.5-100% of the strains. The exception was the BMD-Ac method where trailing growth was not observed. Morphological and ultrastructural alterations were detected in C. tropicalis trailing cells, including mitochondrial swelling and cell walls with irregular shapes. We tested the production of Saps in 13 C. tropicalis strains expressing trailing growth through flow cytometry. Our results showed that all of the C. tropicalis strains up-regulated surface Sap expression after 24 h or 48 h of exposure to fluconazole, which was not observed in untreated yeast strains. We concluded that C. tropicalis strains expressing trailing growth presented some particular features on both biological and ultrastructural levels.

Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth

We assessed fluconazole susceptibility in 52 Candida tropicalis clinical strains using seven antifungal susceptibility methods, including broth microdilution (BMD) [standard M27 A3 (with neutral and acid pH), ATB Fungus 3, Vitek 2 system and flow cytometric analysis] and agar-based methods (disk diffusion and E-test). Trailing growth, detection of cell-associated secreted aspartic proteases (Saps) and morphological and ultrastructural traits of these clinical strains were also examined. The ranges of fluconazole 24 h-minimum inhibitory concentration (MIC) values were similar among all methods. The essential agreement among the methods used for MIC determinations was excellent and all methods categorised all strains as susceptible, except for one strain that showed a minor error. The presence of the trailing effect was assessed by six methods. Trailing positivity was observed for 86.5-100 percent of the strains. The exception was the BMD-Ac method where trailing growth was not observed. Morphological and ultrastructural alterations were detected in C. tropicalis trailing cells, including mitochondrial swelling and cell walls with irregular shapes. We tested the production of Saps in 13 C. tropicalis strains expressing trailing growth through flow cytometry. Our results showed that all of the C. tropicalis strains up-regulated surface Sap expression after 24 h or 48 h of exposure to fluconazole, which was not observed in untreated yeast strains. We concluded that C. tropicalis strains expressing trailing growth presented some particular features on both biological and ultrastructural levels.