Phenotypic and Genotypic Identification of Yeast Species Isolated from Diabetic Foot Patients in Al-Najaf Province, Iraq

Abstract

Opportunistic yeasts, such as Trichosporon and Candida species (spp.), are reported to cause high rates of morbidity and mortality in immunocompromised and underlying patients. This study was conducted to investigate the phenotypic and genotypic identification of yeast spp. isolated from diabetic patients in Al-Najaf province, Iraq. Samples were collected from the depth of diabetic foot patients’ wounds. They were then cultured on Sabouraud Dextrose Agar (SDA) and incubated at 30°C to 35°C for 5 to 7 days for the growth of yeast spp. The colonies were identified based on their microscopic features. Afterward, these yeast samples were cultured in CHROMagar for the isolation and identification of yeast spp. All collected samples were cultured on the SDA through the use of CHROMagar, which is considered a differential agar since the colonies obtained from Candida intermedia and Trichosporon asahii appear in different colors on this media. The Polymerase Chain Reaction assay was performed to amplify the internal transcribed spacer 1 (ITS1) and Internal transcribed spacer 4 (ITS4) sequences for the identification of the yeast spp. Furthermore, the products were sequenced by the Sanger method and compared to the reference global sequences in the national center for biotechnology information Gene Bank. The results showed different molecular sizes of the ITS regions of yeast spp. The primer pair was used for the same sample (i.e., ITS1-ITS4) and targeted the ITS regions. Yeast spp. can be considered the most common fungal agent of life-threatening invasive infections in patients with severe immunodeficiency or underlying diseases, and the treatment of these infections requires long stays in the intensive care units.

Keywords

• candida intermedia
• diabetic
• its1-its4
• trichosporon asahii