PHENOTYPIC AND MOLECULAR IDENTIFICATION OF SOME SPECIES OF CANDIDA SPP.

The correct diagnosis of Candida species is of great importance, because it provides a therapeutic and predictive importance, as it allows for appropriate and early treatment when people are infected. The aim of this study is to confirm the diagnosis of some pathogenic Candida species. The material for this research were 46 isolates collected from the fungi unit in the Department of Biology, College of Science at University of Mosul. Diagnostic tests were conducted, including the phenotypic characteristics of colonies where the external appearance of the colonies was examined growing on the Sabouraud Dextrose Agar was examined and the color of the colony, the whole, its size, its diameter, its height, and its odor were observed, and several biochemical tests were performed, including the growth test on chrom agar candida (CAC) and the chlamydospores formation test using the Tween 80 medium (corn meal agar - CMA), while the germ tube forming test (GTT) was performed according to the Ellis et al., (2007) a pure colony of growing yeast was suspended on SDA solid medium in a sterile test tube containing 0.5 mL of human serum. The mixture was incubated at a temperature of 37 0C for 3 hours, then a drop of the suspension was taken. It was placed on a sterile glass slide and examined under a light microscope to see the germination tube. A polymerase chain reaction (PCR) molecular diagnostics test was also performed, as well as DNA electrophoresis test using agarose gel. The results showed that the diagnosed losses belong to the following species: 41 isolates of Candida albicans with a rate of 89.13%, and 3 isolates belonging to the type Candida glabrata with 6.52%, or one isolate for each of the two species Candida tropicalis, Candida lusitaniae 2.17% for each type. Five types of Candida spp. were identified by PCR technique. The PCR results of the purified DNA samples isolated from the five yeasts and using Internal Transcribed Spacer (ITS) primers showed that 5 bundles of DNA were obtained. Sequencing was performed for the five isolates and then entered into the Basic Local Alignment Search Tool (BLAST) for National Center for Biotechnology Information (NCBI) program to determine the similarity between the isolates and the results in the global gene bank. The sequence results showed that the five isolates matched, in high proportions, with the sequences recorded in the GenBank. We conclude from the study that C. albicans is characterized by its ability to form germination tubes and chlamydia spores, which is a characteristic and diagnostic characteristic of this species. Diagnosis using polymerase chain reaction (PCR) technology is also more accurate compared to the typical and cultured diagnostic methods used in this study. [ABSTRACT FROM AUTHOR]