Análise da sensibilidade para diagnóstico molecular de candidíase

Abstract

Candidiasis is an opportunistic mycosis caused by yeasts of the genus Candida, the species Candida albicans being prevalent in the oral mucosa. However, other yeasts colonize the buccal mucosa and in this case the conventional diagnosis may not be conclusive for the true species causing candidiasis. Thus, the sensitivity threshold for molecular diagnosis of oral candidiasis based on molecular marker analysis using polymerase chain reaction (PCR) was established in this study. For both clinical samples were obtained by scraping the mucosa with swab and inoculated in Sabouraud culture medium. After growth, the genomic DNA of the colonies of C. albicanswas extracted using the organic extraction method with phenol: chloroform. The molecular markers that identify C. albicans were amplified in two rounds in Nested - PCR using the ITS and CALB primers and the results visualized in agarose gel electrophoresis. It has been established that the sensitivity threshold for the primers comprises nanogram concentrations up to 10 pg, the optimum concentrations for visualization on the agarose gel being concentrations between 1ng and 10 pg. In view of the sensitivity presented by the CALB primers, it is suggested later studies that test the sensitivity of these primers in PCR of colony from clinical samples and without the step of DNA extraction.