B.C. MILLAR, J. E. MOORE, J. XU, M. J. WALKER, S. HEDDERWICK AND R. MCMULLAN. 2002. Aims: To determine the frequency, distribution and association of genotypes of Candida albicans and C. dubliniensis in invasive and noninvasive clinical isolates. Methods: Twenty-one invasive and 18 noninvasive isolates were examined by PCR amplification of a transposable intron region in the 25S rRNA gene. Isolates were genotyped following analysis of the size of resulting DNA amplicons. The isolates could be subdivided into four genotypes (A-D). Results: There was no significant difference between the frequency and genotype distribution of the invasive and noninvasive Candida isolates. Impact of the Study: Therapeutic prophylaxis against candidal infections remains an area of controversy. Any diagnostic markers that reflect the potential of isolates to become invasive should be fully explored, so that more focused antifungal intervention should be targeted at these patients with these potential invasive markers. This study demonstrated that analysis of the transposable intron region in the 25S rRNA gene may be useful in helping to differentiate C. albicans from C. dubliniensis isolates, without the need for sequence analysis, which may not be readily available at primary diagnostic laboratories. However, employment of this genotypic assay is not a suitable locus to determine invasiveness and other more reliable markers of invasiveness should be sought.