Publication:

Genotyping and antifungal susceptibility profile of Candida albicans isolated from various clinical samples from tertiary care hospital

Background Genotyping Candida albicans helps identify outbreaks, sources, and virulent and drug-resistant strains. PCR can identify Candida albicans isolates as A, B, or C based on transposable group I introns in 25S rDNA. The length of the amplified product divides C. albicans isolates into genotypes A, B, and C.  Objective of this study was to determine Candida albicans genotypes and antifungal susceptibility in candidiasis patients using PCR.

Methods HIV-positive vaginal and oropharyngeal swabs yielded 126 Candida albicans isolates. Germ tube development, chlamydospore formation, CHROM agar color, sugar fermentation, and auxanographic plate technique with sugar discs identified all C. albicans isolates phenotypically. E-test tested antifungal susceptibility. Genotyping was done using PCR. The Phenol: Chloroform method extracted genomic DNA from all C. albicans isolates. The primer pairs and sequence encompassed the 25Sr DNA transposable intron. 5'-ATA AGG GAA GTC GGC AAA GAT CCG TAA-3' and CA-INT-R (reverse): 5'-CCT TGG CTG TGG TTT CGC TAG ATA GTA GAT-3'.

Results Out of all the 126 profiles, PCR examination of the 25S rDNA transposable group I intron indicated 68.3% genotype A, 10.3% genotype B, and 21.4% genotype C isolates. Genotype A had 16.3% fluconazole resistance, genotype B 7.7%, and genotype C 3.7%. Genotype A strains were resistant to caspofungin, amphotericin B, flucytosine, and voriconazole at 3.5%, 5.8%, 8.1%, and 8.2%. While genotype B and C strains were sensitive.

Conclusions C. albicans genotyping advances drug resistance research. C. albicans molecular typing helps design infection control methods by studying its epidemiology and pathophysiology.