[Dermatophytes transmitted by pets and cattle]. / Dermatophytes transmis par les animaux domestiques.

Most inflammatory skin and hair dermatophytoses are caused by one of four zoophilic dermatophyte species: Microsporum canis (from cats and dogs), Trichophyton verrucosum (from cattle), Arthroderma benhamiae (from Guinea-pigs) and Arthrodermna vanbreuseghemii (generally from cats and dogs). In cases of highly inflammatory tinea corporis, tinea faciae and tinea capitis in humans, it is important to identify with certainty the precise etiologic agent and to examine pets as the possible source of infection. The recurrence of infections or new infections can be prevented by adequately treating incriminated domestic animals and their environments. Cooperation between the medical and veterinary professions is required in this situation.

Dermatophyte identification in skin and hair samples using a simple and reliable nested polymerase chain reaction assay.

BACKGROUND: Dermatophyte identification in tinea capitis is essential for choosing the appropriate treatment and in tinea infections to identify the possible source. The failure of fungi to grow in cultures frequently occurs, especially in cases of previous antifungal therapy. OBJECTIVES: To develop a rapid polymerase chain reaction (PCR) sequencing assay for dermatophyte identification in tinea capitis and tinea corporis. MATERIAL AND METHODS: Fungal DNA was extracted from hair and skin samples that were confirmed to be positive by direct mycological examination. Dermatophytes were identified by the sequence of a 28S ribosomal DNA subunit amplicon generated by nested PCR. RESULTS: Nested PCR was found to be necessary to obtain amplicons in substantial amounts for dermatophyte identification by sequencing. The results agreed with those of classical mycological identification in 14 of 23, 6 of 10, and 20 of 23 cases of tinea capitis, tinea corporis and tinea pedis, respectively, from which a dermatophyte was obtained in culture. In seven of the 56 cases, another dermatophyte was identified, revealing previous misidentification. A dermatophyte was identified in 12 of 18, three of five, and four of nine cases of tinea capitis, tinea corporis and tinea pedis, respectively, in cases in which no dermatophyte grew in culture. CONCLUSIONS: Although the gold standard dermatophyte identification from clinical samples remains fungal cultures, the assay developed in the present study is especially suitable for tinea capitis. Improved sensitivity for the identification of dermatophyte species was obtained as it is possible to identify the dermatophyte when the fungus fails to grow in cultures.