Studying the Subtilisin Virulence Genes (1-7) in Trichophyton Rubrum Isolated from Clinical Samples of Skin and Nail in 2017: A Descriptive Study

The subtilisin genes (SUBs) of Trichophyton rubrum play an important role in destroying the keratin to produce a nutritional source and virulence. This study was carried out to determine the presence of subtilisin genes in T. rubrum isolated from patients with dermatophytosis in Tehran in 2017. This descriptive study was performed on 32 patients with fungal infections referring to Tehran University of Medical Sciences from July to September 2017. Based on microscopic and macroscopic observations, T. rubrum was isolated and identified. Dermatophyte DNA was extracted and SUB1, SUB2, SUB3, SUB4, SUB5, SUB6 and SUB7 genes of T. rubrum were amplified by polymerase chain reaction (PCR) using specific primers. The relative frequency of the seven genomic sequences was also calculated. Seven species of T. rubrum were isolated from the clinical specimen of skin (5 cases) and nail (2 cases). The presence of subtilisin family (SUB1-7) was reported with a frequency of 57%. While SUB5 gene was observed in all isolates (100%), the SUB6 gene with the lowest frequency (4 out of 7 cases) and SUB1-7 genes presence in isolates from nail samples were reported. The presence and absence of subtilisin genes in T. rubrum DNA may indicate the importance of genes in different stages of dermatophyte infection (adherence, invasion and inflammation) and the type of nail and skin structure.