Random Amplified Polymorphic DNA (RAPD) Analysis for Candida parapsilosis Isolates from Blood Cultures

Shin, Jong Hee; Song, Jeong Won; Lim, Woo Hyun; Suh, Soon Pal; Ryang, Dong Wook

Abstract

BACKGROUND
Candida parapsilosis is an important nosocomial pathogen that can form biofilms (slime) on prosthetic material and cause catheter- related bloodstream infections. Genetic heterogeneity has been reported within clinical isolates of C. parapsilosis, but clinical significance of these different genotypes is not clear. We investigated random amplified polymorphic DNA (RAPD) genotypes of bloodstream isolates of C. parapsilosis and their relation to slime production.
METHODS
Twenty-three bloodstream isolates and 20 strains from other sites were analyzed. For RAPD, five random 10-mer primers were used and the results were analyzed by the numerical taxonomy system and multivariate analysis system (NTSYS-pc). Slime production was evaluated by growing the organism in Sabouraud broth with 8% glucose and examining the walls of the tubes for the presence of an adherent slime layer.
RESULTS
RAPD analysis separated 43 isolates of C. parapsilosis into four distinct genotypes. All 23 blood isolates belonged to type I, whereas the isolates from other sites consisted of type I (n=13), II (n=2), III (n=2) and IV (n=3). Eighty-three percent (19/23) of blood isolates were slime positive, whereas 50% (10/20) of isolates from other sites were slime positive. Slime positivity was observed in 81% (29/36) of type I isolates, in contrast to 0% (0/7) in all other types (types II~V).
CONCLUSION
We suggest that C. parapsilosis isolates, which produce slime, are possibly of the same or similar RAPD type.