Fourier transform infrared spectral evaluation for the differentiation of clinically relevant Trichophyton species

Routine mold identification methods have been established to provide actual data to facilitate reliable diagnoses in clinical laboratories, as well as the management of infection and health practice planning, particularly for dermatophytes. Some species of the Trichophyton genera, particularly T. rubrum and T. mentagrophytes complexes, exhibit more complexity in species recognition. In this study, the intriguing technique of Fourier-transform infrared (FT-IR) spectroscopy is evaluated for species recognition of Trichophyton spp. A total of 32 reference isolates, belonging to T. mentagrophytes (n=7), T. rubrum (n=21) complexes and Arthroderma spp. (n=4), were included in the study. Numerous spectral window FTIR spectroscopy data were analyzed by principal component analysis and hierarchical clustering was performed. There were not any spectral ranges presenting clusters at the main Trichophyton species (e.g. T. rubrum, T. mentagrophytes and Arthroderma spp.). Notably, only T. violaceum (including T. yaoundei and T. soudanense) was clustered in several ranges. In intra-species evaluation, T. erinacei, belonging to the T. mentagrophytes complex, was distinguishable by FT-IR spectroscopy with different spectral range calculations. We suggested that further research with several reference and clinical isolates of Trichophyton species will be crucial to accurately identify intra-species of T. rubrum and T. mentagrophytes complexes.