Acta Médica Costarricense
version ISSN 0001-6012
SALAS-CAMPOS, Ingrid and GROSS-MARTINEZ, Norma T. Etiological agents of onychomycosis diagnosed in the medical mycology laboratory of the University of Costa Rica. Acta méd. costarric [online]. 2012, vol.54, n.2, pp. 114-118. ISSN 0001-6012.
Background and aim: Among the onychodistrophies, onychomycosis are the most frequently encountered. This infection not only constitutes an esthetic problem for the patients, but can also affect their daily activities. For dermatologists, it is crucial to make a differential diagnosis; thus, the medical mycology laboratory plays an important role to achieve this purpose. The fungal agents most frequently encountered are the dermatophytes, however, other filamentous non-dermatophyte fungi have been isolated and are known to be less susceptible to antifungals. In the present work, the frequency of onychomycosis among patients attending the medical mycology laboratory, UCR, was studied during four years, according to the age and sex of the patients, as well as the isolated etiological agents identified. Methods: The study included all patients that requested the community service provided by the Department of Medical Mycology, School of Microbiology, UCR, between January 2007 and December 2010 and that showed nail alterations suspicious for onychomycosis. The age and sex of each patient were registered and samples were processed for direct microscopy and culture. Results: A total of 431 nail samples were collected, of which 85.4% were toenails and 14.6% fingernails. The mean age of the patients was 49 years, of which 64% were females and 36% males. Onychomycosis was diagnosed, either by direct microscopy and culture, or only with positive direct microscopy, in 73.4% of the sample population, of which 89.4% were toenails and 10.6% fingernails. Trichophyton rubrum was the etiological agent most frequently isolated from toenails, followed by Fusarium spp. C albicans was the most frequent fungal agent observed in fingernails. Conclusion: The diagnosis of onychomycosis relies upon both the clinical and laboratory diagnosis. Dermatophytes, yeasts and non-dermatophyte filamentous fungi were identified in the population studied. These findings should be considered due to their implications to the choice of the most appropriate treatment.
Keywords : onychodystrophies; onychomycosis; dermatophytes; filamentous non dermatophyte fungi.