The Prevalence of Onychomycosis in the Zagreb Area – the Role of Sabouraud Agar without Cycloheximide in Diagnosis and Therapy

Abstract

Mycological analysis is considered the gold standard in the diagnosis of very common fungal diseases of nails. The purpose of the article is to present the prevalence of onychomycosis obtained by using direct microscopic examination (DME) and cultivation on Sabouraud media without cycloheximide. The quantitative retrospective research was conducted on 2706 patients of both sexes (mostly middle-aged to elderly) with various toenail lesions, who had undergone mycological analyses in the Mycological Laboratory of our Department of Dermatovenereology in 2013 and 2014. Analysis of the results obtained revealed that there were 35.4% of positive DME results; of these, there were 39.2% of dermatophytes, 59.1% of yeasts and 1.7% of molds. The percentage of dermatophytes (Trichophyton spp.) was twice as high in men as in women. A considerable percentage (12%) of mixed isolates was also observed. Particularly worrisome was the high percentage (one-third) of suppressed and insufficiently developed dermatophytes (a possible indicator of inappropriate preparation of patients for mycological analysis). Cultivation on culture media without cycloheximide requires frequent inspections because of the fast-growing molds while not allowing sporulation for a great number of dermatophytes. However, it has certain advantages, i.e. it offers an insight into the wide range of the present fungi. As part of the biofilm, they can be potentially pathogenic in dystrophic nails under certain circumstances because, according to our results, the percentage of dermatophytes does not change substantially with aging; however, what does change is the percentage of molds, yeasts and mixed isolates.

Keywords

• Mycological examination
• Onychomycosis
• Dermatophytes
• Nails
• Biofilms
• Non-dermatophyte fungi