Detection of antifungal drug-resistant and ERG11 gene mutations among clinical isolates of Candida species isolated from Khartoum, Sudan.

Abstract

Background: Candida species are one of the most important opportunistic fungal pathogens that cause both superficial and systemic infections, especially in immunocompromised individuals. Considering the sharp increase in the rate of Candida infections, and resistance to commonly used antifungal agents in the last decades; this study was conducted to determine the rate of resistance among clinical isolates of Candida species, and to characterize some of the resistant genes among resistant isolates collected in Khartoum.  Methods: This is a cross-sectional laboratory-based study included 100 pre-screened Candida species isolates from Khartoum state hospitals. Chromogenic media was used for Candida isolation and/or identification. The standard disc diffusion method was performed to investigate the susceptibility to fluconazole, itraconazole, and amphotericin. Following genomic DNA extraction, the entire ERG11 gene was amplified from some C. albicans resistant isolates, sequenced, and further analyzed. Results: Out of 100 clinical isolates collected, 51% were C. albicans, followed by C. glabrata (31%), C. krusie (8%), C. tropicals (5%), and C. dupliniens (5%). Resistance rate was 23% for fluconazole, 4% for itraconazole, while there were no amphotericin resistant isolates detected. C. albicans ERG11 gene sequence reveals 15 different mutations. Among these, three (D116E, E266D, and V488I) were missense mutations; however, these substitutions do not contribute to fluconazole resistance. Conclusion: C. albicans was found to be the most common species. Resistance against fluconazole was observed most frequently; however, mutations in ERG11 are unlikely to be the reason behind fluconazole resistance among these isolates.