Enhanced Enzymatic Activity of Yeast-like Fungi Responsible for Onychomycosis in Renal Transplant Recipients

BACKGROUND: Renal transplant recipients (RTR) are regarded as a group especially predisposed to onychomycosis. The exact mechanism of increased frequency of onychomycosis in RTR is however not fully understood. OBJECTIVES: This study was undertaken to evaluate activity of hydrolitic enzymes of fungi most commonly causing fungal nail infections in RTR and to compare it with enzymatic activity of the same fungi isolated from lesional nails in immunocompetent patients. MATERIAL AND METHODS: 28 strains of yeast-like fungi cultured from lesional nails in RTR and 25 strains of yeasts isolated from changed nails in immunocompetent patients were included into the study. All fungi were identified on the basis of routine mycological procedures. Activity of 19 hydrolytic enzymes was assessed by API ZYMÒ test (bioMerieux). RESULTS: Fungi cultured from RTR showed activity of 16 out of 19 enzymes, whereas fungi isolated from immunocompetent patients only 11 out of 19 enzymes. Moreover, yeast-like fungi isolated from RTR showed higher generally higher activity of detected enzymes compared to yeast strains obtained from the lesional nails of immunocompetent patients. CONCLUSIONS: This study shows for the first time enhanced enzymatic activity of yeast-like fungi isolated from lesional nails in RTR in comparison to fungi cultured from changed nails in immunocompetent patients. It is hypothesized that this enhanced enzymatic activity may be responsible for higher incidence of onychomycosis in RTR.