Species-specific fatty acid methyl ester research as a biological indicator in the diagnosis and differential diagnosis of candida albicans and candida dubliniensis with the translational medicine perspective

Introduction and Purpose: Candida species may act as an opportunistic pathogen in case of weakening of the host defense system and cause infections called as candidiasis. Because of the similar phenotypic and genotypic aspects, Candida albicans (C.albicans) and Candida dubliniensis (C.dubliniensis) have difficulties in the diagnosis and differential diagnosis. Since Candida albicans and Candida dubliniensis species differ in their resistance to antifungals, their differential diagnosis is particularly important in immunodeficient patients. Although many isolates of C. dubliniensis are sensitive to antifungals, they can develop resistance by expressing multidrug transporter genes. The MIDI Sherlock Microbial Identification System provides the identification of microorganisms by analyzing species-specific microbial fatty acid methyl esters (FAME) with gas chromatography(GC). Objective: Determination of 'Mininmum Inhibition Concentration' (MIC) values of fluconazole and amphotericin B antifungals of C.albicans ATCC 10231 and C.dubliniensis CD36 standard strains, evaluation of biofilm formation under antifungal effect and determination of fatty acid profiles. Method: Candida albicans ATCC10231 and Candida dubliniensis CD36 standard strains were prepared for analysis of cellular fatty acids. To determine the Minimum Inhibition Concentration (MIC) values of amphotericin B antifungals, European Antimicrobial Susceptibility Test Committee (EUCAST) liquid micro dilution method was used. Biofilm evaluation of strains under antifungal effect was performed by crystal violet staining method. 4 Results: The amphotericin B MIC concentration for C.albicans ATCC 10231 strain was 64 µg / ml. Amphotericin B MIC concentration for C.dubliniensis CD36 strain 64 µg / ml. It was determined that C. albicans ATCC 10231 and C. dubliniensis CD36 strains which were not exposed to antifungal were biofilm. The strains were also found to produce biofilm at amphotericin B MIC concentrations. C.dubliniensis CD36 was found to be more potent to the surface than C.albicans ATCC 10231. MIC and subMIC concentrations of amphotericin B antifungalin lead to inhibition of the biofilm formation of C.dubliniensis CD36 strain, while MIC concentration was determined not to cause a significant inhibition of C.albicans ATCC 10231 strain, and biofilm formation was significantly increased at sub-MIC concentrations It was identified that there were two reference peaks specific for C.albicans ATCC 10231 strain and a specific reference peak for C.dubliniensis CD36 strain. A total of six common fatty acid reference peaks were obtained, one of which had different branching properties. Conclusion:. Although MIC concentrations of C.dubliniensis CD36 and C.albicans ATCC 10231 were the same for amphotericin B antifungal, C.dubliniensis CD36 was found to be more potent to the surface. Although C. dubliniensis CD36 was more strongly adherent to the surface, it was found that the inhibition effect of amphotericin B antifungalin was higher than that of C.albicans ATCC 10231. The results show that species-specific diagnostic markers that can be obtained in the analysis of strains that are morphologically and genotypically similar to each other are extremely important in diagnosing and monitoring the course of the infection. Key Words: Candida albicans, Candida dubliniensis, Minimum Inhibitory Concentration (MIC), Fatty Acid Profiles