Molecular identification and in-vitro antifungal susceptibility testing of Candida species isolated from patients with onychomycosis

Abstract

Background and Purpose: Candida species are the most opportunistic fungi affecting the nails and resulting in onychomycosis. In this study, we identified and evaluated in-vitro susceptibility of the recovered isolates against fluconazole (FLC), voriconazole (VRC), and clotrimazole (CLT) using the Clinical and Laboratory Standards Institute (CLSI) M27-A3 document.Materials and Methods:From patients with either clinically or mycologically proven onychomycosis, 97 isolates comprising of seven Candida species were isolated, which were identified by both conventional and molecular techniques such as polymerase chain reaction-restriction fragment length polymorphism. In addition, Candida dubliniensis was confirmed by restriction endonuclease analysis. Antifungal susceptibility of each isolate against the three azoles applied in this study was determined using the CLSI microdilution reference method M27-A3. Results: Candida parapsilosis (C. parapsilosis) was the most frequently isolated species (n=44), followed by C. albicans (n=23), C. tropicalis (n=13), C. glabrata (n=7), C. krusei (n=6), C. guilliermondii (n=3), and C. dubliniensis (n=1). All the isolates were susceptible to CLT. VRC had lower minimum inhibitory concentration (MIC) values for the isolates compared to FLC. Geometric mean MIC values of VRC, FLC, and CLT for C. parapsilosis isolates were 0.07 μg/ml, 0.8 μg/ml, and 0.35 μg/ml, respectively. Collectively, all species exhibited greater susceptibility to VRC in comparison to C. albicans (P≤0.001).Conclusion:This study showed that non-albicans Candida species were the most common etiologic agents of non-dermatophyte onychomycosis. The major antifungal agents used in clinics to empirically treat yeast onychomycosis are FLC and CLT. Our data suggested that CLT is a better choice for the treatment of Candida onychomycosis, especially in drug resistant cases.

Mycological Aspects of Onychomycosis in Khuzestan Province, Iran, a New Scenario as Shift from Dermatophytes towards Yeasts

“…Such results were in agreement with reports from Brazil, India, Saudi Arabia, and Iran [ 5 , 9 , 10 , 21 , 23 ]. The frequency of Candida albicans (50%) as the main Candida species causing onychomycosis in this study was lower than 58-68% reported from Qazvin and Isfahan provinces [ 9 , 11 ], but was higher than 23-45% from Shiraz, Tehran, and Kermanshah [ 12 , 13 , 26 ].…”

Relationship between antifungal susceptibility profile and virulence factors in Candida albicans isolated from nail specimens

“…According to the present results, which are supported by previous studies, susceptibility to AMB and VRC was detected in C. albicans isolates 24,25 . In contrast, Pakshir et al reported that 43% of C. albicans isolates from patients with onychomycosis were resistant to VRC in Iran 26 . In addition, our results showed that 11.4% and 8.6% of C. albicans isolates were resistant to FLC and ITC, respectively.…”

An alarming rise of non-albicans Candida species and uncommon yeasts in the clinical samples; a combination of various molecular techniques for identification of etiologic agents

“…In the last two They showed frequencies of (10%) and (11.1%) for C. glabrata, respectively (27,28). Interestingly, Pakshir et al (29) showed C. parapsilosis as the most prevalent Candida species collected from fingernail infections (45.3%), even higher than C. albicans (23.7%). Non-albicans Candida infections may have more incidence among patients with allogeneic hepatocyte transplantation, neutropenia, hematologic malignancies, and severe immune suppression (30,31) however, in our study, there was no difference between neutropenia and malignancies with C. albicans or NAC infections.…”