RESUMEN
To determine the role and pattern of non-dermatophyte moulds as causative agents of onychomycosis. Case series. Department of Microbiology, Armed Forces Institute of Pathology [AFIP], Rawalpindi, from November 2009 to July 2010. Nail clippings and nail scrapings were obtained from abnormal looking nails with treatment and detection failure for onychomycosis. Microscopic [40% potassium hydroxide mounts] examination and culture on Sabouraud's dextrose agar [SDA], SDA containing chloramphenicol, and SDA containing actidione and chloramphenicol were used for species identification. Non-dermatophyte moulds were isolated from 32 out of the total 47 culture positive cases [68%]. Alternaria alternata was the commonest species [46%]. Dermatophytes were isolated from only 7 patients [15%] belonging to genus Trichophyton. Yeasts were isolated in 8 [17%]. There was no fungal growth in 53% of cases. The non-dermatophytes should be considered important in evaluating the culture negative cases for dermatophytes as well as those cases ending up in treatment failure after empirical treatment for dermatophyte infections