Morphology,molecular Identification And Antifungal Susceptibility Testing Of Clinical Trichophyton Mentagrophytes Strains Isolated From Different Part Of The Body

Object: According to epidemiological,clinical and host criteria,it has long been admitted that the Trichophyton mentagrophytes species includes two varieties: a zoophilic variety and an anthropophilic variety that involve the upper and the lower part of the body,respectively.In this study,the Trichophyton mentagrophytes isolated from different parts of the patients were investgated from four aspects: morphology,physiological test,molecular biology and drug sensitivity test,so as to determine whether there were differences between them.Methods: A total of 48 clinical strains of Trichophyton mentagrophytes originally indentified according to their phynotypic characteristics were collected from out-patient department.In this study,the morphological characteristics and the physiological test were analyzed to determine whether there existed some difference among them.In addition,sequencing of their PCR products targeting ITS and D1-D2 regions was underwent,and the phylogenetic trees on these targets were further established according to the maximum likelihood method.Furthermore,the sensitivities of these strains to 8 antifungal drugs including fluconazole,flucytosine,itraconazole,ketoconazole,terbinafine,voriconazole,miconazole and luliconazole were detected according to M38-A2 protocol by CLSI.Results: Trichophyton mentagrophytes isolated from different parts of the body showed consistency in morphology and urease test,but the hair perforation test showed different characteristics.Both the phylogenetic trees mentioned above suggested that all the 48 clinical isolates were clustered in the Trichophyton interdigitale clade;The identifying efficiency of ITS target was superior to 28 S rDNA D1-D2 region.Among the 8 antifungal drugs,luliconazole and terbinafine had the relatively lower MIC values,flucytosine had the highest MIC value for the Trichophyton mentagrophytes strains.The MIC values of terbinafine and miconazole against the strains isolated from the upper body were significantly higher than those of isolated from the lower part of the body.Conclusions: Trichophyton mentagrophytes strains isolated from upper and lower parts of the body were unanimously identified as Trichophyton interdigitale at species level,but there exists discrepancy in hair perforation test and their sensitivities to the above-mentioned antifungal agents.