Resistance or Decreased Susceptibility to Fluconazole in Candida Species Isolated from Solid Organ Transplant Recipients: An Emerging Challenge

Abstract

Background: Candida infections are the most prevalent type of fungal infections in solid organ transplant (SOT) recipients. Emerging pathogens and resistance to antifungal drugs are concerning issues in organ recipients.

Objective: Regarding universal prophylaxis treatment in SOT recipients, particularly with fluconazole, and emergence the of rare species causing infections, the present study was conducted to species identification and antifungal susceptibility profiles of yeasts isolated from SOT recipients.

Methods: All adult patients undergone solid organ transplantation in Abu-Ali Sina transplant center were included with six six-month follow-up. Isolation of Candida species from clinical samples was performed using culture on Sabouraud Dextrose Agar (SDA) and CHROMagar Candida. Species identification was performed by ITS1-5.8SITS2 gene sequencing. Antifungal susceptibility testing to fluconazole, itraconazole, voriconazole, caspofungin, and amphotericin B was determined according to the micro broth dilution method documented by CLSI.

Results: During the study period, 28 of 383 adult solid organ transplant recipients developed at least one positive culture of yeast species isolated from different clinical specimens. The incidence rate of invasive candidiasis was 2.6%. Candiduria was the most prevalent type of involvement by Candida species. The most frequent isolated species was C. albicans (22/54, 40.7%), followed by C. glabrata (11/54, 20.3%), and C. parapsilosis (9/54, 16.7%). Resistance or decreased susceptibility to fluconazole was found in more than half of isolates, and also 13% of isolates were known cross-resistant to different azole antifungal drugs.

Conclusion: Our finding supports the need to perform antifungal susceptibility testing of yeast isolates in immunocompromised patients to guide proper treatment.