Sterol composition of Cryptococcus neoformans in the presence and absence of fluconazole
| Autor: | B. Currie, J. A. Ritchie, Brad Spellberg, A. Casadevall, J.E. Edwards, Mahmoud A. Ghannoum, Ashraf S. Ibrahim, E. D. Spitzer |
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| Rok vydání: | 1994 |
| Předmět: |
Microbial Sensitivity Tests
Microbiology chemistry.chemical_compound Ergosterol polycyclic compounds medicine Humans Pharmacology (medical) Candida albicans Fluconazole Pharmacology Cryptococcus neoformans biology Cholestadienols Phytosterols Fungi imperfecti biology.organism_classification Sterol In vitro Yeast Sterols Infectious Diseases chemistry lipids (amino acids peptides and proteins) Research Article medicine.drug |
| Zdroj: | Antimicrobial Agents and Chemotherapy. 38:2029-2033 |
| ISSN: | 1098-6596 0066-4804 |
| Popis: | Analysis of the sterol compositions of 13 clinical isolates of the pathogenic yeast Cryptococcus neoformans obtained from five patients with recurring cryptococcal meningitis showed that, unlike Candida albicans, the major sterols synthesized by this yeast were obtusifoliol (range, 21.1 to 68.2%) and ergosterol (range, 0.0 to 46.5%). There was considerable variation in the sterol contents among the 13 isolates, with total sterol contents ranging from 0.31 to 5.9% of dry weight. The isolates from the five patients who had relapses had different total sterol contents and compositions in comparison with those of the pretreatment isolates, indicating either that the sterols had been changed by therapy or that the patients were infected with new isolates with different sterol compositions. Growth of the cryptococcal isolates in the presence of subinhibitory concentrations of fluconazole (0.25x the MIC) significantly altered the sterol content and pattern. The total sterol content decreased in nine isolates and increased in four isolates in response to pretreatment with fluconazole. Fluconazole had no consistent effect on ergosterol levels. In contrast, fluconazole caused a decrease in obtusifoliol levels and an increase in 4,14-dimethylzymosterol levels in all isolates. These results indicate extensive diversity in sterol content, sterol composition, and sterol synthesis in response to subinhibitory concentrations of fluconazole in C. neoformans strains. We propose that fluconazole inhibits the sterol synthesis of C. neoformans by interfering with both 14 alpha-demethylase-dependent and -independent pathways. No correlation between the sterol compositions of C. neoformans isolates and their susceptibilities to fluconazole was found. |
| Databáze: | OpenAIRE |
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