In vitro evaluation of the susceptibility of fungi isolated from clinical materials to Voriconazole

A.B. Macura, B. Pawlik and A. Szul

Author address: 

Microbiology, Mycology, Krakow, Poland

Abstract: 

The objective of the study was in vitro evaluation of the susceptibility of 103 fungal strains to Voriconazole. The fungi were isolated from clinical materials: sputum, bronchial lavage, stool, urine, vaginal smears, skin and nails. A slide-dilution method was applied: the drug tested was incorporated into YNB medium (Yeast Nitrogen Base) at concentrations 0.1, 1, 10 and 100 mg l-1. Fungal cultures on YNB without the drug added served as controls. Sixty-three strains of yeast-like fungi were evaluated after 48 h incubation at 37 C. Eighteen mould strains were evaluated after 72 h incubation at 27 C. The outcome was recorded as either total or partial growth inhibition. Additionally, 22 dermatophyte strains were evaluated after 7 and 14 day incubation at 27 C. The drug at concentration 0.1 mg l-1 inhibited 17.5% of the yeast-like fungal strains; 1 mg l-1 23.8%; 10 mg l-1 33.3%. The remaining 25.4% of the strains were inhibited at 100 mg l-1. Considerably, lower drug concentration was sufficient to partially inhibit fungal growth: 0.1 mg l-1 50.8%; 1 mg l-1 44.4%; 10 mg l-1 4.8%. Low values of fungal growth inhibiting concentration were found with other than C. albicans Candida strains (C. glabrata, C. krusei, C. kefyr, C. guilliermondii). In the 18mould strains, total growth inhibition was achieved at 0.1 mg l-1 in 11.1% of them, at 1 mg l-1 in 66.7%, at 10 and 100 mg l-1 in 11.1% each. Partial growth inhibition, when compared with controls, occurred at 0.1 mg l-1 in 72.2% of the strains, at 1 mg l-1 in 22.2%. Only a single strain (5.5%) was inhibited at 10 mg l-1. Very low inhibiting concentrations were found with Aspergillus fumigatus. Voriconazole turned out to be particularly effective against dermatophytes. No matter whether the culture was evaluated after 7 or 14 days, the growth of 95.5% of the strains was totally inhibited at concentration of 1 mg l-1. The strains of Trichophyton mentagrophytes and Trichophyton rubrum were most susceptible to Voriconazole. It is noticeable that Voriconazole is especially effective against A. fumigatus and other than C. albicans yeast-like fungi which may be beneficial in the mycoses caused by those fungal species.
2005

abstract No: 

P017

Full conference title: 

2nd Trends in Medical Mycology
    • TIMM 2nd (2010)