3 DISTINCT GENOTYPES WITHIN CANDIDA-PARAPSILOSIS FROM CLINICAL SOURCES

Three genetically distinct groups of Candida parapsilosis were detecte d among clinical isolates. These were distinguishable on the basis of isoenzyme profiles and DNA sequences of internally transcribed spacer (ITS) sequences flanking the 5,8S RNA gene, In an investigation of 45 strains, including 32 clinical isolates from Texas, C. parapsilosis gr oup I composed the majority of the common clinical isolates. The type strain of C. parapsilosis was a member of this group. The 10 group II isolates were indistinguishable from group I strains when tested,vith the API 20C kit. The two group III isolates differed from those in gro ups I and II by being D-xylitol positive by the API 20C kit; however, isolates in all groups assimilated D-xylitol from broth. Isoenzyme pro files excluded the close relationship of any of these groups to Lodder omyces elongisporus, which is a teleomorphic yeast that has a physiolo gical profile similar to that of C. parapsilosis, Although there were insignificant differences in the ITS2 rDNA sequences, comparisons of t he ITS1 sequences revealed several differences. A sequence analysis of ITS1 in which missing bases were counted as mismatches showed the fol lowing similarities: group I versus group II, 87.7%; group I versus gr oup III, 82.1%; group II versus group III, 84.5%, Also, the activity o f secreted proteinase showed differences among the three groups, with many group I isolates having moderate to high activity, The degree of susceptibility to antifungal agents, amphotericin B, ketoconazole, and 5-fluorocytosine, could not be used to determine an isolate's group.