Isolation, characterization, and molecular identification of Candida species from urinary tract infections


1 Student Research Committee, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran

2 Department of Bacteriology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran

3 Department of Pathobiology, School of Veterinary Medicine, University of Tabriz, Tabriz, Iran

4 Statistical Researcher, Faculty of Electronic Unit, Islamic Azad University, Tehran, Iran


Background and Purpose: Candida species are reportedly the most common human fungal pathogens. The incidence of urinary tract infections (UTIs) caused by Candida pathogens has increased in recent decades. However, such infections rarely occur in the absence of any predisposing factors. Regarding this, the aim of the present study was to identify the Candida species causing UTIs and determine the predisposing factors for candiduria.

Materials and Methods: The current study was conducted on 1,450 urine samples obtained from patients suspected of UTI. Out of this number, 19 cases were candidiasis, and 2 cases were mixed infections caused by bacteria and fungi. Candida species were diagnosed differentially using the germ tube test, colony staining on CHROMagar medium, intracellular beta-glucosidase enzyme activity, and glucose absorption pattern. Then, the colonies with the same morphology were confirmed by the DNA sequencing of internal transcribed spacer regions.

Results: According to the results, 38%, 28.6%, 14.3%, and 9.5% of the isolates were identified as C. albicans, C. glabrata, C. tropicalis, and C. kefir/C. krusei, respectively. The presence of one or more predisposing factors was proved in all patients in whom diabetes was the most prevalent predisposing factor (21.1%).

Conclusion: Based on the obtained results, C. albicans species was the most prevalent fungal species. In addition, urinary fungal infections were less prevalent than bacterial urinary infections.