Molecular analysis and dimorphism of azole-susceptible and resistant Candida albicans isolates

Abstract

Introduction: Candida albicans is responsible for superficial or systemic infections known as candidiasis, which may be found in infected tissue as unicellular budding yeasts, hyphae, or pseudohyphae. In this study, the effects of both fluconazole and itraconazole antifungal agents on the hyphal formation and genotypic characterization of C. albicans isolates classified as either susceptible or resistant were investigated. Methods: The hyphal production of five C. albicans isolates under the action of antifungal agents was investigated by culturing yeast on growth medium and on hyphal induction medium. The genotypic characterization was carried out for 13 isolates of C. albicans using the random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) method. Results: The dimorphism analysis showed that the hyphal formation was higher in resistant than in the susceptible isolates to both azoles. The RAPD-PCR method identified the formation of two different groups. In group A, four resistant and two susceptible isolates were clustered, and in group B, one resistant and six susceptible isolates were clustered. Conclusions: Considering that hyphal formation was higher in resistant isolates in the presence of azole drugs, we confirmed that the hyphal production is closely related to susceptibility to azoles. These drugs may affect the morphogenesis of C. albicans depending on their susceptibility to these drugs. In relation to RAPD-PCR, most resistant isolates classified in group A and susceptible isolates in group B demonstrated that this method presented a similar standard between the two groups, suggesting that by this technique, a strong correlation between genotypes and fluconazole-resistant samples may be found.

Linking Cellular Morphogenesis with Antifungal Treatment and Susceptibility in Candida Pathogens

“…It has been observed that there is a correlation between resistance to antifungals and the ability to undergo filamentous growth [161,169]. For azoles, when C. albicans clinical isolates with variable levels of resistance to azole antifungals were grown under filament-inducing conditions, and, in the presence of an azole drug, drug-resistant isolates were able to form hyphae more efficiently than susceptible isolates [161,170]. In C. lusitaniae , there is also an association between resistance to the polyene amphotericin B, and pseudohyphal filamentation: phenotypic switching produces a distinct phenotype (dark brown colony pigmentation on copper sulfate media), which is associated with both pseudohyphal growth as well as an slightly elevated MIC relative to the dominant “light brown” phenotype [50].…”

Glutathione levels in and total antioxidant capacity of Candida sp. cells exposed to oxidative stress caused by hydrogen peroxide

“…are more resistant to oxidative stress 10 , and hyphal formation is higher in isolates resistant to azole drugs 11 . Taking into account these data, overcoming the oxidative phagocytic challenge seems to be critical for the establishment of candidemia.…”

Effects of Rosmarinus officinalis essential oil on germ tube formation by Candida albicans isolated from denture wearers

“…Candida albicans is the primary fungal species associated with oral candidiasis, can adhere to and colonize denture resins, and contributes to denture-related stomatitis, during which the yeast may form germ tubes and hyphae 1 . Candida albicans virulence depends on its ability to transform between the yeast and fi lamentous (pseudohyphae or true hyphae) forms 2 ; the latter is induced in human infections 3 .…”