Utility of a pre-optimized kit for random amplified polymorphic DNA in typing Candida albicans

The utility of a pre-optimized kit for random amplified polymorphic DNA (RAPD) was assessed in typing diverse strains of Candida albicans from epidemiologically unrelated inpatients (interpatient analysis) and in detecting clonal variations that maybe present within individual patient isolates (intrapatient analysis). Stool samples from inpatients were cultured on Inhibitory Mold agar. Nine individual colonies from all patients with > or =9 colonies of C. albicans (n = 18) were selected, frozen, and karyotyped using CHEF genomic DNA plug kits and CHEF-DRIII. Each of the selected colonies was then analyzed by RAPD, utilizing the selected kit, with 6 primers. Interpatient analysis revealed 9 karyotypes and 17 RAPD composites. RAPD discrimination was significantly better (p < 0.001). Intrapatient analysis revealed 34 (21%) and 33 (20.4%) variants among 162 colonies tested by RAPD and karyotyping, respectively. The results were discordant in 25 variants, all with differences of 1-3 bands. These results illustrate that this pre-optimized kit for RAPD provides excellent discrimination of genetically unrelated strains. Its performance in delineating subtle clonal differences was comparable with karyotyping; both methods failed to detect all minor genetic variations. The ease of use and quick turnaround time of this kit offer a practical and reliable method for typing diverse strains of C. albicans, but may be inadequate for assessing microevolution.