Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth

Memórias do Instituto Oswaldo Cruz

Marcos Dornelas-ribeiro²  Eliane Olmo Pinheiro¹  Carolina Guerra¹  Lys Adriana Braga-silva¹  Silvia Maia Faria De Carvalho¹  André Luis Souza Dos Santos¹  Sonia Rozental¹  Sergio Eduardo Longo Fracalanzza¹ 

[1] ,Instituto de Biologia do Exército Laboratório de Bacteriologia/Micologia Rio de Janeiro RJ ,Brasil

关键词: Candida tropicalis;    antifungal susceptibility test;    trailing growth;    biological and ultrastructural alterations;    aspartic protease production;   

DOI  :  10.1590/S0074-02762012000100005

来源: SciELO

【 摘 要 】

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.

【 授权许可】

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