Phenotypic heterogeneity of dermatophytes (trichophyton rubrum complex, trichophyton mentagrophytes complex and microsporum canis) detailed from clinical samples

OBJECTIVE: Conventional and molecular methods are used in the diagnosis of dermatophytes. The aim of this study was to investigate the heterogenity of dermatophytes isolated from clinical specimens by conventional methods. MATERIALS AND METHODS: This study was done in Ege University Medical Faculty Hospital, Medical Microbiology-Mycology Laboratory in August 2015 - March 2017. Dermatophytes examined: A total of 100 dermatophytes were examined. Of these, 70 were T.rubrum, 20 were M. canis and 10 were T.mentagrophytes complex. Conventional diagnostic methods: Direct microscopic examination with 10% KOH and lactophenol cotton blue, mycological cultures were performed using Sabouraud dextrose agar (SDA) and potato dextrose agar (PDA) media. Supplemental tests: Hair perforation test and urease test were done. In addition, radial origin in dermatophytes was measured rapidly. RESULTS: In the study, 73% of the clinical specimens examined in culture were found to have fungal element in direct microscopic examination, while 27% did not have fungal element. Two different micromorphologies were identified in the abstracted T.rubrum complex strains. Micromorphologically; The number of strains seen in microconidium was 28 (40%), microconidium and macroconidium were seen in 42 (60%). According to the colony surface appearance of T.rubrum complex strains; 33 (47%) of the dermatophytes were flat and 37 (53%) of them were fluffy. Colony pattern: Hairy 41 (59%), 29 (41%) was cottony. Colony color: from the top; white 31 (44%), yellow 39 (56%). Colony base color: red 33 (47%), yellow / orange 37 (53%). All 20 strains of M.canis were abstracted with thick,rough-walled macroconidium. According to the colony surface appearance flat 13 (65%), fluffy 7 (35%). Colony pattern: Hairy 4 (20%) and 16 (80%) was velvety. Colony color : 2 (10%) were white from the top, the base is yellow; 18 (80%) were yellow from the top and the bottom was yellow. Microscopic examination of 10 abstracted T.mentagrophyes complex strain revealed spiral hyphae as well as macro / microconidium. The colony surfaces were flat, powdery. When examined in terms of pigmentation, from the top 2 (20%) were yellowish to white and 8 (80%) were yellowish. Base colors were 3 (30%) yellow / cream and 7 (70%) were brown. In hair perforation test; M.canis strains showed ectothrix, eight of the complex origin of T.mentagrophytes showed endothrix involvement. Two of the T.mentagrophytes strains and the T.rubrum complex strains were negative for the hair-perforation test. In the urease experiment; T.rubrum complex strains were evaluated as urease negative. All of M.canis and T.mentagrophytes were positive for urease. In colony radial growth rate examination, it was determined that T.mentagrophytes complex and M.canis strains exhibited relatively faster radial growth than T.rubrum complex. CONCLUSION: In this study, three different types of dermatophytes were examined by conventional methods and additional biochemical and physiological tests and phenotypic diversity was investigated.