[In vitro antifungal susceptibility of dematiaceous filamentous fungi using the E-test].
The usefulness of the E-test((R) )has been studied to determine the in vitro susceptibility of 52 isolates of 17 species to five antifungal drugs: amphotericin B, 5-flucytosine, ketoconazole, itraconazole and fluconazole. Minimal inhibitory concentrations were determined following the manufacturers' instructions, except in the preparation of the inoculum. In this case a spectrophotometric method was used to obtain 1-5 ' 10(6) CFU/ml. Two different culture media were included: casitone-agar and RPMI 1640 agar. Most isolates showed clear growth in both media after 96 h of incubation at 37 degrees C. The species showed low MIC concentrations to ketoconazole and itraconazole. Only 55.8% of isolates showed MICs </= 2 mg/l to amphotericin B and 98% of strains presented MICs of 32 mg/l for 5-flucytosine. With the exception of one isolate, the remaining were resistant to fluconazole with MIC values 256 mg/l. No differences were found between the MICs for the two media, but values were easier to read in casitone-agar. These results suggest that itraconazole and ketoconazole should be the antifungals of first choice for treating infections due to the evaluated species. This study showed that the E-test((R) )appears to be a suitable method for testing the susceptibility of dematiaceous filamentous fungi to antifungals.
Vivas
J R
JR
Departamento de Parasitología y Microbiología, Escuela de Medicina, Universidad de Oriente, Ciudad Bolívar, Venezuela.
Torres-Rodríguez
J M
JM
D000362:Agar; D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003470:Culture Media; D004058:Diffusion; D025141:Drug Resistance, Fungal; D015725:Fluconazole / Q000494:pharmacology; D005437:Flucytosine / Q000494:pharmacology; D017964:Itraconazole / Q000494:pharmacology; D007654:Ketoconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000295:instrumentation; D003904:Mitosporic Fungi / Q000187:drug effects*
D000935:Antifungal Agents; D003470:Culture Media; D017964:Itraconazole; D000666:Amphotericin B; D015725:Fluconazole; D000362:Agar; D005437:Flucytosine; D007654:Ketoconazole