Antifungal susceptibility of dermatophytes from racehorses in Japan.

BACKGROUND: Luliconazole (LCZ) is an imidazole antifungal medication that exhibits excellent activity against dermatophytes. As a topical cream and lotion (approved for human use), LCZ has demonstrated a broad spectrum of activity against human dermatophytoses. OBJECTIVES: This is the first study to investigate the in vitro susceptibility of clinical isolates from horse dermatophytoses to LCZ. ANIMALS: No animals were used in this study. METHODS AND MATERIALS: In the present study, the in vitro susceptibilities of clinical isolates of dermatophytes to LCZ, clotrimazole (CTZ), miconazole (MCZ) and terbinafine (TRF) were investigated using the Clinical & Laboratory Standards Institute M38-A2 test. RESULTS: The minimum inhibitory concentrations (MICs) for all 16 clinical isolates of Trichophyton equinum, Microsporum equinum/canis and M. gypseum for LCZ were <0.03 mg/L. The MICs of all isolates were <0.03-0.5 mg/L for CTZ, 0.03-16 mg/L for MCZ and <0.03-1 mg/L for TRF. CONCLUSIONS: LCZ demonstrated a broad spectrum of activity against clinical isolates from horse dermatophytoses. We consider that LCZ will become the primary antifungal agent for treating horse dermatophytosis.

The Clonal Population of Trichophyton equinum from Dermatophytoses of Japanese Racehorses.

Trichophyton equinum is a zoophilic dermatophyte that is frequently isolated from horse dermatophytosis and rare infections in humans. In the present study, molecular and physiological testing were performed on T. equinum isolates from dermatophytoses of Japanese racehorses to assess genotype and phenotype patterns of these strains. Comparative nucleotide sequence analysis showed that internal transcribed spacer (ITS) region sequences amplified from all Japanese isolates were 99.5% identical to T. equinum reference strains. ITS sequences amplified among the isolates were 100% (BT2) showed that isolates were 100% identical and harbored a "T" single nucleotide polymorphism at position 18. The sequences of ß-tubulin (BT2) showed that isolates were 100% identical to T. equinum reference strains. The MAT1-2 allele was detected by PCR in all seven isolates, whereas none of the isolates contained the MAT1-1 allele. All isolates grew only on Trichophyton Agar 5 and did not grow on Trichophyton Agar 1 and 4, indicating nicotinic acid requirement. These results suggest that Japanese T. equinum isolates are derived from a clonal population.