Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth
Mem. Inst. Oswaldo Cruz
;
107(1): 31-38, Feb. 2012. ilus, tab
Article
in English
| LILACS
| ID: lil-612803
ABSTRACT
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.
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Index:
LILACS (Americas)
Main subject:
Fluconazole
/
Candida tropicalis
/
Antifungal Agents
Limits:
Humans
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
2012
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Hospital Adventista Silvestre/BR
/
Instituto Estadual de Hematologia/BR
/
Instituto de Biologia do Exército/BR
/
Universidade Federal do Rio de Janeiro/BR
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