Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014118 (endocarditis)
 15,629 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the development and potential mechanisms of antifungal resistance in relation to antifungal exposure, reversible fluconazole resistance was examined in vitro. Candida albicans ATCC 36082 blastospores were passed in liquid yeast nitrogen base medium containing either 4, 8, 16, or 128 micrograms of fluconazole per ml, and susceptibility testing was performed after each passage. High-level fluconazole resistance (50% inhibitory concentration, > 256 micrograms/ml) developed in the isolates after serial passage in medium containing 8, 16, or 128 micrograms of fluconazole per ml, but not in isolates passed in 4 micrograms of fluconazole per ml. Reduced susceptibility was noted within four to seven passages, which was equivalent to 14 to 19 days of exposure to the drug. However, all isolates returned to the susceptible phenotype after 8 to 15 passages in medium lacking the drug; thus, fluconazole resistance was reversible in vitro. In vivo, organisms retained the resistant phenotype after a single passage in the rabbit model of infective endocarditis. Restriction digest profiles and karyotypic analysis of the parent strain and selected fluconazole-resistant and -susceptible isolates from each group were identical. Investigations into the molecular mechanisms of this reversible resistance failed to reveal increased accumulation of mRNA for 14 alpha-demethylase, the target enzyme for fluconazole, or for the candidal multidrug transporters CDR1 and BENr. This process of continuous in vitro exposure to antifungal drug may be useful as a model for studying the effects of different antifungal agents and dosing regimens on the development of resistance and for defining the mechanism(s) of reversible resistance.
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PMID:Reversible fluconazole resistance in Candida albicans: a potential in vitro model. 905 88

The past two decades have witnessed an increase in serious fungal infections, without corresponding growth in available antifungal agents. Voriconazole (VRC) is a novel triazole antifungal, recently approved in Europe for treatment of serious infections caused by Aspergillus, Fusarium, Scedosporium, and resistant Candida species. Voriconazole has in vitro activity against yeasts and yeast-like fungi similar, or superior to, fluconazole (FLC), itraconazole (ITC) and amphotericin B (AMB). Candida albicans is generally the most susceptible yeast (VRC MIC subset90 of 0.06 microg/ml); C. krusei often has low MICs even in the face of FLU/ITC resistance. Voriconazole has demonstrated comparable, or better, in vitro activity than ITC and AMB against Aspergillus (mean MICs 0.19-0.58 microg/ml), Ascomycetes, Bipolaris, Fusarium, Blastomyces dermatitidis, Coccidioides immitis, dermatophytes, Histoplasma capsulatum, Malassezia, and Scedosporium angiospermum (P. boydii). The drug possesses potent fungicidal activity against moulds including Aspergillus, Scedosporium, and Fusarium. Fungicidal activity is likely due to the high affinity of VRC for fungal 14-alpha-demethylase, a concept supported by ultrastructural and biochemical analysis. Animal studies confirmed the activity of VRC against infections including pulmonary and invasive aspergillosis (IA); A. fumigatus endocarditis; fusariosis; pulmonary cryptococcosis; and invasive candidiasis. Most importantly, well-designed human clinical trials have confirmed the efficacy of VRC in the treatment of candidal esophagitis, IA, and febrile neutropenia. Smaller studies and case reports have shown VRC is useful for salvage therapy of IA, cerebral aspergillosis, Scedosporium, and other fungal infections. Clinical testing has shown VRC is safe and well tolerated; the most common side effect is benign, self-limited visual disturbance.
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PMID:Voriconazole -- better chances for patients with invasive mycoses. 1206 15