Recently Malassezia (M.) furfur fungemia has been increasingly recognized in premature infants and adults receiving parenteral nutrition. Accordingly, analysis of nucleic acids in M. furfur serovars and strain typing methods based on genetic differences and similarities are required for epidemiological studies.

This study was done to analyze nucleic acids in M. furfur serovars A, B and C and to adapt the method of restriction fragment length polymorphism (RFLP) analysis of DNA to differentiate the strains of M. furfur serovars for use in epidemiological studies.

Cellular nucleic acids were extracted from the strains of M. furfur serovars and electrophoresed, followed by digestion of DNA and electrophoresis of the resultant DNA fragmegments.

Each of the six strains, grown both on solid medium and liquid medium, revealed a genomic DNA. Interestingly, unique extra bands of RNA were observed in four of the six strains which had grown on solid medium. These bands were also seen in three of them grown in broth. The size of these bands were from 0.5 to 5.0 kbp by comparison with a ‘1 kb DNA ladder’. The restriction patterns generated by EcoR I, Hae III, Hind III, and Hinf I were not unsuccessful. The DNA from serovar B was insensitive to the above restriction enzymes.

Although DNA was extracted from the strains, the amounts were not thought to be enough for RFLP analysis and the DNA from the serovar B was insensitive to the above restriction enzymes. Thus, further development of an extraction method of DNA is required for obtaining enough DNA from M. furfur serovars, and other restriction enzymes would have to be investigated for their ability to differentiate strains of M. furfur in epidemiological studies. Also, further investigation of RNA bands might be able to adapt them for a typing method.