Three kinds of rapid DNA probe-based diagnostic tests for detecting pathogenic fungi in sterile body fluids (blood and urine) will be developed: a general fungal screen, a Candida yeast screen, and several organism-specific tests. Ability to detect viable and inviable organisms in the blood of patients with suspected systemic infection will result in fewer at-risk individuals subjected to unnecessary traumatic antifungal drug therapy and fewer suffering from undiagnosed fungemia. Specific cDNA probes for C. albicans and other Candida species will be synthesized, following reverse- transcription (RT) sequencing of the highly variable V4 regions of the 18S ribosomal RNAs (rRNAs) of certain Candida species. The complete sequences of C. albicans 18S and 25S rRNAs will be determined by DNA sequencing rRNA gene clones and then aligned with complete sequences from other fungi, other eukaryotes, and prokaryotes. Conserved and divergent regions will be used to design """"""""consensus"""""""" and additional organism-specific cDNA probes, respectively. Probe specificity will be refined by RT sequencing of selected regions of individual organisms. Technology for nonradioactive detection of Campylobacter developed by our Phase III partner, GENE-TRAK Systems, will be adapted for use with fungal cDNA probes and clinical samples from systemic candidiasis patients. Large-scale field trials of the test(s) will be initiated.
