Random Amplified Polymorphic DNA (RAPD) Analysis for Aspergillus Species Isolated from Clinical Specimens

Shin, Jong Hee; Lee, Chang Jae; Lee, Jee Yeon; Song, Jeong Won; Kee, Seong Jung; Suh, Soon Pal; Ryang, Dong Wook

Abstract

BACKGROUND: Aspergillus species are second only to Candida species as the most commonly isolated fungi from clinical specimens. As well as the identification of the Aspergillus species, it has been necessary for epidemiological studies to differentiate between strains of the same species. We performed genotypic identification and characterization of species and strains within the genus Aspergillus by using RAPD.
METHODS
A total of 63 clinical strains of Aspergillus species (including 21 A. fumigatus, 12 A. flavus, 12 A. niger, 12 A. terreus, 3 A. nidulans, and 3 A. sydowii) from 63 patients was analyzed. For RAPD alanysis, M13 primer (5'GAGGGTGGCGGTTCT3') and five random 10-mer primers (OPC-6, 7, 10, 18 and 20; Operon Technologies, USA) were used.
RESULTS
The RAPD patterns by M13 primer appeared to be identical when the isolates of the same Aspergillus species were compared. Distinctive and reproducible sets of amplification products by primer M13 were observed for different Aspergillus species: 60 of 63 (95%) isolates were correctly identified by the RAPD analysis using primer M13. RAPD patterns obtained from different strains of the same Aspergillus species by five OPC primers were far more similar than those derived from different Aspergillus species, but the RAPD profiles with some OPC primers showed polymorphism among isolates of the same Aspergillus species. The application of some OPC primers made it possible to cluster the isolates of the same Aspergillus species into several groups.
CONCLUSION
These results indicate that RAPD can be useful for the rapid identification of Aspergillus species and for strain typing in the epidemiological investigations.