|Von Oy, Sabina|
Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2002
Publication Date: 6/1/2002
Citation: RIGBY, S., PROCOP, G.W., HAASE, G., WILSON, D., HALL, G., KURTZMAN, C.P., OLIVEIRA, K., VON OY, S., HYLDIG-NIELSEN, J.J., COULL, J. RAPID IDENTIFICATION OF CANDIDA ALBICANS DIRECTLY FROM YEAST POSITIVE BLOODCULTURE BOTTLES BY FLUORESCENCE IN SITU HYBRIDIZATION USING PNA PROBES. JOURNAL OF CLINICAL MICROBIOLOGY. 2002. V. 40. P. 2182-2186. Interpretive Summary: Rapid detection and identification of yeasts and other fungi in blood supplies is a major problem in medicine because infusing contaminated blood can lead to patient death. This paper reports on a rapid method for detecting the pathogenic yeast Candida albicans in human blood through use of a molecular probe based on an extensive gene sequence database developed at NCAUR. The probe uses protein nucleic acid (PNA) technology developed by Boston Probes, Inc. and has an attached fluorescein label for detection under a fluorescence microscope. The method provides definitive identification of C. albicans in blood samples in the very short time of 2.5 hours.
Technical Abstract: A new fluorescence in situ hybridization (FISH) method using peptide nucleic acid (PNA) probes for identification of Candida albicans directly from yeast-positive blood culture bottles is described. The test (C. albicans PNA FISH) is based on a fluorescein-labeled PNA probe targeting C. albicans 26S rRNA. The PNA probe is added to smears made directly from the blood culture bottle and hybridized for 90 min at 55 C. Unhybridized PNA probe is removed by washing (30 min) and the smears are examined by fluorescence microscopy. The specificity was confirmed using 23 reference strains representing phylogenetically related yeast species and 148 clinical isolates covering the clinically most significant yeast species, including C. dubliniensis, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis. The performance of C. albicans PNA FISH as a diagnostic test was evaluated using 33 routine and 25 simulated yeast-positive blood culture bottles and showed 100% sensitivity and 100% specificity. It is concluded that this 2.5-hour method for definitive identification of C. albicans directly from yeast-positive blood culture bottles provides important information for optimal antifungal therapy and patient management.