Importance of Potato-Dextrose Agar medium in isolation and identification of fungi of the genus Fusarium obtained from clinical materials.

Introduction: Routine mycological diagnostic for culturing of fungi isolated from the skin changes recommends Sabouraud agar with antibiotics and a selective Sabouraud agar with antibiotics and cycloheximide. Although the introduction of a selective medium with Actidion facilitates isolation of dermatophytes, but also inhibits the growth of other fungi present on the skin - an ecological niche, a especially rich in micro-fungi including molds, which include the genus Fusarium. Aim: The aim of this study was to analyze several cases of hyalohyphomycosis caused by Fusarium solani and F. oxysporum, and note that occasional quotations of fungi of the genus Fusarium can be the result of shortcomings in the standard diagnostics. Material and methods: The research material was represented by swabs and fragments of necrotic tissue from inflammatory focus of surgical wound of the lower leg (1 case), and from toe nail shaft, from which Candida albicans was previously isolated (3 cases). For mycological analysis were used: direct preparations stained with Gram method of biological materials and macrocultures, in isotonic 0.9% NaCl; macrocultures on Sabouraud agar with chloramphenicol and gentamicin, Sabouraud agar with chloramphenicol and Actidion, Czapek-Dox agar and PDA (Potato-Dextrose Agar); microculture on Nickerson agar with the addition of broth with serum in a 1:1 ratio. The course of diagnostic, the method of culturing of fungi and the criteria required for taxonomic evaluation were consistent with the generally accepted recommendations for mycological laboratories. Adequately to the aim of the work, particular attention was focused on the criteria considered in identification of the species of the genus Fusarium. Results: The use of PDA agar has allowed the isolation of two species of Fusarium: F. solani (Mart.) Sacc. from the surgical wound and nail shaft and F. oxysporum Schlecht. from the nail shaft. On media recommended in the routine mycological diagnostic the growth of these species was not characteristic. Conclusions: An occasional isolations of fungi of the genus Fusarium from skin lesions may be caused by Actidion added to the standard Sabouraud media as an inhibitor of mold growth. Medium PDA - optimal for capturing phytopathogens potentially pathogenic for humans - should be introduced into routine diagnostics of fungi isolated from skin lesions and surgical wounds. [ABSTRACT FROM AUTHOR]