Molecular identification of dermatophytes isolated from sheep and goats in Zaria, Nigeria

Abstract

Dermatophytosis is a contagious superficial mycosis caused by a group related fungi in the Genera Trichophyton, Microsporum and Epidermophyton. Early and accurate identification of the causative agent of dermatophytosis is essential for effective treatment and prevention of the disease. Genotypic techniques are more rapid, sensitive and specific than the conventional methods. However, there is a paucity of information on molecular characterization of dermatophytes from domesticated ruminants, particularly in northern Nigeria. The aim of this work was to carry out molecular identification of dermatophytes isolated from sheep and goats in Zaria. Ninety-four goats and 63 sheep skin scrapings were aseptically collected from suspected cases of deramtophytosis. Each specimen was processed for direct microscopic examination and, cultural isolation and phenotypic identification of etiologic agents. The identified dermatophyte isolates were subjected to DNA extraction followed by amplification of the internal transcribed spacer (ITS) regions of their ribosomal DNA. The dermatophytes were identified by comparing the sizes of the amplified ITS regions of each isolate with ITS regions sizes of dermatophytes reported in the literature. Out of the 34 dermatophyte isolates from both sheep and goats, 23 were phenotypically identified as Trichophyton mentagrophytes while 11 were T. verrucosum. The PCR based technique identified 23 of the isolates as T. mentagrophytes while 11 were identified as T. verrucosum in complete agreement with the culture method. The sizes of the ITS regions of all the T. mentagrophytes and T. verrucosum were approximately 600bp except one isolate of T. mentagrophytes which had ITS region size of approximately 550bp. Trichophyton verrucosum and T. mentagrophytes isolated from sheep and goats were successfully identified by PCR method targeting the ITS regions of their ribosomal DNA. As far as we know, this is the first report of molecular identification of dermatophytes isolates from small ruminants in northern Nigeria.