Phylogenetic relationship of Fusarium species isolated from keratitis using TEF1 and RPB2 gene sequences

Fusarium species are known to be one of the common causes of keratitis. This study was conducted to identify Fusarium spp. causing keratitis and to investigate their genetic diversity using TEF1 and RPB2 gene sequences.

Twenty-four clinical isolates of Fusarium were isolated from the patient with keratitis. Phylogenetic analysis of two-locus of the 24 clinical isolates and three reference strains was carried out using the maximum parsimony and RAxML methods.

Based on gene sequences of the 24 clinical isolates, 17, 4, and 3 isolates were identified as Fusarium solani species complex (FSSC), Fusarium fujikuroi species complex (FFSC), and Fusarium oxysporum, respectively. FFSC include F. proliferatum (n=1), F. globosum (n=1), F. verticillioides (n=1), and F. brevicatenulatum (n=1), respectively.

Given that sequence of a sole gene can be challenging and on the other hand, due to the high resistance to antifungal drugs, identification of Fusarium species is of substantial significance. In this study, by designing a novel set of primers for the RPB2 area and using TEF1 primer, we were able to differentiate 24 Fusarium spp. isolated from patients with keratitis.