Evaluation of susceptibility of Trichophyton mentagrophytes and Trichophyton rubrum clinical isolates to antifungal drugs using a modified CLSI microdilution method (M38-A)

Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil Correspondence Maria Elisabete da Silva Barros betebarros{at}ef.ufop.br Received 25 January 2006 Accepted 12 December 2006 Onychomycosis is a common adult human mycosis, and dermatophytes of the Trichophyton genera are the most common causative agent. Many antimycotic agents are safe and highly effective for the treatment of dermatophytosis, and are available for clinical practice. Successful treatment depends on the ability of antifungal drugs to eradicate the fungal isolates. The aim of this work was to determine the MICs of four antifungal drugs (fluconazole, itraconazole, terbinafine and griseofulvin) recognized for ungual dermatophytosis treatment caused by Trichophyton species, especially Trichophyton mentagrophytes and Trichophyton rubrum . MICs were determined using a broth microdilution method in accordance with Clinical and Laboratory Standards Institute approved standard M38-A with some modifications, such as an incubation temperature of 28 °C, an incubation time of 7 days and inocula constituted of only microconidia. The results showed that the activities of terbinafine and itraconazole were significantly higher (MICs of