Genomic diversity of oral Candida krusei isolates as revealed by DNA fingerprinting and electrophoretic karyotyping

Abstract

Candida krusei is receiving increasing attention as an important human pathogen, especially in compromised patients, who frequently manifest with multiepisodes of candidosis. As there is scant information on the genetic diversity of this pathogen the present study was undertaken to establish its genetic profiles using three different typing methods: PFGE (pulsed-field gel electrophoresis), RFLP (restriction fragment length polymorphism), RAPD (randomly amplified polymorphic DNA). When 11 oral isolates of C. krusei were molecular typed by PFGE, 3 to 5 chromosomes with sizes ranging from 1000 kb to 3000 kb per isolate were revealed. All isolates produced a single bright band at approximately 1,100 kb and two to three bands between 2,500 kb and 3,000 kb, demonstrating 5 different karyotypes. RFLP with HinfI yielded 9 different genotypes, while DNA fingerprinting by RAPD with 3 primers (RSD6 (5′GCGATCCCCA3′), RSD7 (5′AGTGAATTCG CGGTGAGATGCC3′) and RSD12 (5′GCATATCAATAAGC GCAGGAAAAG 3′)), resulted in 8, 3 and 11 different genotypes, respectively. This study provides evidence hitherto unavailable on the genetic polymorphism of C. krusei isolates colonizing the oral niche under different clinical conditions. Such genotypic polymorphism should help strain delineation in epidemiologic surveillance of either nosocomial or community outbreaks of C. krusei infections.