Related Experiment Videos
In vitro sensitivity of medically significant Fusarium species to various antimycotics
A S Sekhon1, A A Padhye, A K Garg
1National Centre for Human Mycotic Diseases, University of Alberta Hospitals, Edmonton, Canada.
Abstract:
Sixteen isolates belonging to Fusarium chlamydosporum (n = 4), Fusarium equiseti (n = 1), Fusarium moniliforme (n = 2), Fusarium oxysporum (n = 3), Fusarium proliferatum (n = 1), and Fusarium solani (n = 5) were tested against amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, ketoconazole, JAI-amphotericin B (water-soluble compound), hamycin and amphotericin B combined with 5-fluorocytosine, using antibiotic medium M3, high-resolution broth (pH 7.1), Sabouraud's dextrose, and yeast-nitrogen broth media (1 ml/tube). The minimal inhibitory and minimal fungicidal concentrations of 5-fluorocytosine and fluconazole for all species were > 100 micrograms/ml. All Fusarium isolates, except F. equiseti (3.125 micrograms), gave minimal inhibitory concentrations of 12.5-100 micrograms/ml for hamycin. The values for amphotericin B, itraconazole, ketoconazole, JAI-amphotericin B, and amphotericin B combined with 5-fluorocytosine were 1.56-100, 0.78-50, 3.125-100,50-100, and 1.56 to > 100 micrograms/ml, respectively. Although a wide range of minimal inhibitory concentrations was recorded for most of the isolates studied, it appears that some--F. solani, F. oxysporum, F. chlamydosporum, F. equiseti, and F. moliniforme--were more susceptible to amphotericin B, itraconazole, ketoconazole, hamycin, and amphotericin B in the presence of 5-fluorocytosine. All isolates showed resistance to 5-fluorocytosine and fluconazole. The minimal fungicidal concentrations were either the same or several times higher than the minimal inhibitory concentrations.
Insights
This study evaluated antifungal susceptibility in Fusarium species. Most Fusarium isolates showed susceptibility to amphotericin B and itraconazole, but resistance to fluconazole.
Area of Science:
- Mycology
- Antimicrobial Susceptibility Testing
Background:
- Fusarium species are opportunistic fungal pathogens.
- Antifungal resistance is a growing concern in managing Fusarium infections.
Purpose of the Study:
- To determine the in vitro antifungal susceptibility profiles of various Fusarium species.
- To compare the efficacy of different antifungal agents against Fusarium isolates.
Main Methods:
- Sixteen Fusarium isolates (F. chlamydosporum, F. equiseti, F. moniliforme, F. oxysporum, F. proliferatum, F. solani) were tested.
- Antifungal susceptibility was assessed using minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) assays.
- Tested antifungals included amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, ketoconazole, JAI-amphotericin B, hamycin, and combination therapies.
Main Results:
- All Fusarium isolates exhibited resistance to 5-fluorocytosine and fluconazole (MIC > 100 µg/ml).
- Hamycin showed variable efficacy (MIC 12.5-100 µg/ml), with F. equiseti being more susceptible.
- Amphotericin B, itraconazole, and ketoconazole demonstrated broad activity (MICs ranging from 0.78 to 100 µg/ml).
- Certain isolates (F. solani, F. oxysporum, F. chlamydosporum, F. equiseti, F. moliniforme) were more susceptible to amphotericin B, itraconazole, ketoconazole, hamycin, and amphotericin B with 5-fluorocytosine.
Conclusions:
- Fusarium species display significant resistance to fluconazole and 5-fluorocytosine.
- Amphotericin B and itraconazole are promising agents for treating Fusarium infections.
- Further research into combination therapies may enhance treatment efficacy.