Abstract

Abstract Objective(s): the current study aims at isolating Cryptococcus neoformans yeast from cancer patients and identifying them genetically, depending on Ribosomal internal transcript spacer DNA, using the specific primer ITS_CN4 and CN5_CN6 in Nested PCR Technique. Methodology: this yeast has been isolated from hospitalized patients in the hospitals of Najaf Governorate from cancer male and female patients in Najaf Governorate, having different ages from (1-45) years old. The yeasts have been phenotypically identified using traditional methods and biochemical tests. The yeasts have been identified as Cryptococcus neformans yeasts using VIEK2 system. Out of 57 samples taken from cancer patients, 21 isolates were isolated from Cryptococcus; 15 isolates from C. neoformans, 5 isolates from C. albidus, and one isolate from C. laurentii. The results of amplification using the (CN4,ITS) showed bands with size of 415 base pairs, but only for 14 C. neoformans isolates. However, the other two types showed no band. The (CN6_CN5) delivered bands with 116 base pairs for 20 isolates common among the three species. The statistical programme spss was used to calculate the final results of the study. Results: Cr.neoformans yeast was the most frequent isolates as compared with the other species. Nested PCR method gave the best of the results concerning the identification and genetic convergence among the species. Results of identification using the VIEK2 system were identical to those gotten via this method, using the (CN5_CN6) more than those gotten using the first pair (CN4, ITS). Conclusion: most of the infections in Cryptococcus neoformans were in city patients; among age category from (16-30) years old, as the most infected age category. Recommendations: Depending on the Nested PCR Technique in identification, as it is an accurate method that can be used for genotype identification and classification of that yeast.