Characterization and antifungal drug profile of Dermatophytes from clinical sources in Nairobi, Kenya
Dermatophytes are fungi that invade the keratinized tissue (skin, hair and nail) to produce infections referred to as dermatophysis. The severity of dermatophysis may be as a result of the host reactions to the metabolic products of the fungus, the anatomic location of the infection, the virulence of the infecting species, the immune status of the patient and local environmental factors. The HIV / AIDS and other immunocompromised infections and diseases have led to the steady rise in opportunistic fungal infections including dermatophytes. When incorrect diagnosis, treatment and management of dermatophysis are encountered, it leads to predisposition to secondary bacterial and other microbial infections, scarring and drug resistant strains are created. Data have shown that there has been a steady rise of these infections from patients attending a clinical laboratory. Increasing concerns are evidenced on the genotypic and phenotypic characteristics of these dermatophytes and why the relapse infections. These observations are explained by incorrect diagnosis, excessive use over the counter drugs or mutated and drug resistant dermatophytes. This study aimed at characterizing dermatophytes isolated from clinical sources by conventional and molecular typing methods. The study also determined the antifungal drug patterns of the isolated organisms. The dermatophytes were identified by conventional culture techniques and molecular methods. In vitro activity against triazoles and azoles antifungals drug profile was determined in accordance to Clinical and Laboratory Standards Institute (CLSI) M 38-A document. Results of the study revealed that dermatophytic and non dermatophytic infections were isolated from the study population, with the genera of Trichophyton being the most commonly isolated dermatophyte. Tinea corporis (23%) showed the highest manifestation of dermatomycoses followed by Tinea capitis (14%) respectively. The commonly isolated dermatophytes were Trichophyton rubrum (16%), Trichophyton mentagrophyte (14%), Trichophyton terrestre (12%) and Trichophyton violaceum (10%) respectively. There was a significant variation in the prevalence of the different dermatophytes was at (P = O.Oll).The molecular characterizations of the isolates were more sensitive compared to the conventional methods because it correctly identified Chrysosporium keratinophilum species that had been wrongly identified by the conventional methods. The antifungal assay showed that among the Azoles Fluconazole was resistant to all the isolated tested against. Posiconazole and Isaconazole were the most potent drugs against dermatophysis.