DNA Fingerprinting of Candida albicans Strains Isolated from Candidemic Patients by Polymerase Chain Reaction and Southern Hybridization Methods

Park, Ju Yeoul; Shin, Jong Hee; Yang, Sung Jin; Oh, Bong Joon; Cho, Duck; Kee, Seong Jung; Shin, Myung Gun; Suh, Soon Pal; Ryang, Dong Wook

Abstract

BACKGROUND: Although several molecular typing methods have been used to investigate C. albicans infections, there remains no "gold standard" method by which relatedness of C. albicans strains is determined. In this study, two DNA fingerprinting methods were compared for genotyping of clinical strains of C. albicans isolated from candidemic patients.
MATERIALS AND METHODS
Twenty-nine strains of C. albicans isolated from various clinical specimens (14 from blood, 7 from catheter, 4 from respiratory tract secretion, and 4 from urine) of 14 candidemic patients were analyzed. Primer 1245 and 1246 were employed for IR PCR and Southern blot hybridization method was used for C2 fingerprinting, with Ca3 and C1 as primers, after the fragmentation of DNA with EcoR1
RESULTS
IR PCR method separated 29 isolates into 9 (1245 primer), 7 (1246 primer) and 14 (combination of two primers) types, whereas C1 fingerprinting identified 16 different types. By combining the IR PCR and C1 fingerprinting methods, total of 16 different genotypes were identified among 29 isolates from 14 patients, which is the same result obtained by the C1 fingerprinting only. Using both methods, blood and non-blood isolates from each patient produced identical genotypes for 10 patients and different genotypes for 1 patient. In three patients, isolates from blood and other site of each patient showed identical patterns by IR PCR fingerprinting, but appeared different (n=1) or similar (n=2) by C1 fingerprinting. Overall, for 87% (13/15) of patients, isolates collected from catheter (6 of 7 patients), urine (4 of 4 patients), or respiratory (3 of 4 patients) were identical or similar to the corresponding blood isolates.
CONCLUSION
Our study shows that C1 fingerprinting method is more discriminatory than IR PCR for the molecular typing of C. albicans isolates. For the majority of patients, blood and other site isolates had identical or similar genotypes.