ORIGINAL RESEARCH article
Front. Fungal Biol.
Sec. Fungal Genomics and Evolution
Fluconazole resistance among Candida species with special emphasis on ERG11 gene mutations among Candida tropicalis
Provisionally accepted
Vidyavathi B Chitharagi1Gowthami S1
Sumana Mahadevaiah1Morubagal Raghavendra Rao1Sowmya G S1
Yogeesh D Maheshwarappa1,2*- 1Department of Microbiology, JSS Medical College and Hospital, JSS Academy of Higher Education and Research, Mysuru, India
- 2JSS Medical College & Hospital, JSS Academy of Higher Education and Research, Mysore, India
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Introduction: Candidiasis, an opportunistic fungal infection, is increasingly caused by non-albicans Candida species that show reduced fluconazole susceptibility, mainly due to ERG11 overexpression. This study aimed to identify Candida species, determine fluconazole resistance using VITEK 2 and disc diffusion methods, and detect ERG11 gene mutations in Candida tropicalis Methodology: A total of 410 clinical samples were included in this laboratory-based prospective experimental study conducted at a tertiary care hospital in Mysuru. Fluconazole-resistant Candida species were identified using the Vitek-2 system and disc diffusion methods. The ERG11 gene of fluconazole-resistant strains of Candida tropicalis was amplified by polymerase chain reaction (PCR) and subjected to high-resolution melt (HRM) analysis to detect ERG11 mutations. Results: A total of 410 Candida species were isolated during the study period, with 61% (250/410) from males and 39% (160/410) from females. Among the 410 isolates tested by Vitek-2, 29 (7.07%) were resistant to fluconazole, with the majority being C. tropicalis (51.7%). Of the 15 C. tropicalis isolates tested, A395T and C461T mutations in the ERG11 gene were detected in 6 isolates. These isolates showed high minimum inhibitory concentrations (MICs) to azoles. Discrepancies between Vitek-2 and PCR findings likely reflect the multifactorial nature of fluconazole resistance and the presence of resistance mechanisms beyond the targeted ERG11 mutations Conclusion: The study concludes that antifungal susceptibility testing (AST) using Vitek-2 is a preferred method in the laboratory for identifying Candida species and performing susceptibility testing due to its ease of use and cost-effectiveness. Disc diffusion can be utilised in resource-limited settings to guide treatment, while PCR and newer molecular methods offer valuable opportunities for researching different mechanisms and mutations responsible for fluconazole resistance, a widely used antifungal for treatment and prevention.
Keywords: Azole resistance, Candida isolates, Candida tropicalis, ERG11 mutation, Fluconazole resistance, Polymerase Chain Reaction
Received: 29 Aug 2025; Accepted: 04 Dec 2025.
Copyright: © 2025 Chitharagi, S, Mahadevaiah, Rao, S and Maheshwarappa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yogeesh D Maheshwarappa
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