Molecular Identification of Candida albicans and C. dubliniensis Using Small Subunit rRNA Gene Sequence in Kerbala, Iraq

This study was conducted to confirm the phenotypic diagnosis of two Candida species, including Candida albicans (C. albicans) and Candida dubliniensis (C. dubliniensis). They were previously isolated in another study from cases of oral candidiasis using polymerase chain reaction and determining the nitrogenous base sequences of the 18 SrRNA product duplication using the NS1 and NS8 primers. The sequences of the multiple bases were analyzed using the Basic Local Alignment Search Tool program (BLAST), which proved that the two diagnosed Candida strains belong to two species, including C. albicans and C. dubliniensis, respectively. Additionally, the comparison of these sequences to the data available in the National Center for Biotechnology Information (NCBI) database showed that C. albicans strains in this study were 99% similar to the universal strains of C. albicans from Japan, Brazil, the United States, Germany, India, China, Pakistan, and Egypt. The C. dubliniensis strains in this study also had the highest genetic similarity rate of 99% to the C. dubliniensis strains isolated from the United States, Netherlands, France, and Germany. The study strains were recorded in the GenBank database with the sequence codes MZ574137 and MZ574410.1 for C. albicans and C. dubliniensis, respectively. The results of the 18 SrRNA region’s duplication also showed variations between C. albicans and C. dubliniensis, represented by the presence of three mutations of the first type and two mutations in the second type at different sequence sites.