Identification of subtilisin virulence genes (SUB1-7) in Epidermophyton floccosum isolated from patients with dermatophytosis in Iran

Abstract

BackgroundDermatophytes are a group of frequent cutaneous infectious agents with different clinical forms, which are highly adapted to invade the enriched keratin tissues, through secretion of different enzymatic and non- enzymatic virulence factors. Since the knowledge of the factors mediating invasion of Epidermophyton floccosum to host tissues is little known, we investigated the harborage of SUB genes family in clinical isolates of E. floccosum. Material and methodsA total, 312 clinically suspected cases of dermatophytosis were investigated in Medical Parasitology and Mycology Laboratory, Tehran University of Medical Sciences. All the obtained specimens underwent direct examination and culture on Sabouraud Dextrose Agar with Chloramphenicol and Cycloheximide. Molecular confirmation of dermatophytes was performed using ITS1 and ITS4 primers. Finally, the presence of SUB gene family in clinical isolates and the reference strain of E. floccosum were evaluated using specific primers. ResultsConsidering our results, the presence of SUB2, SUB3, and SUB7 was demonstrated in 10 isolates of E. floccosum derived from different clinical forms of dermatophytosis, including tinea cruris (n = 7), tinea pedis (n = 2), and tinea corporis (n = 1). Also, SUB1 and SUB6 were only detected in 3 (3/10), and 2 (2/10) isolates of E. floccosum, respectively. Nevertheless, the results of the current study showed that there are no isolates to carry SUB4 and SUB5 genes. ConclusionsIn the current study, the presence of SUB2, SUB3, and SUB7 in all of the investigated isolates probably implies their indispensable role in infection elicitation. Further studies are needed to investigate the key role of subtilisin genes and check the conditions that affect the expression of SUB genes in vitro and in vivo.