Published in:
01-05-2012 | Article
Validation of a modified algorithm for the identification of yeast isolates using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)
Authors:
B. H. Van Herendael, P. Bruynseels, M. Bensaid, T. Boekhout, T. De Baere, I. Surmont, A. H. Mertens
Published in:
European Journal of Clinical Microbiology & Infectious Diseases
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Issue 5/2012
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Abstract
Optimising antifungal treatment requires the fast and species-specific identification of yeast isolates. We evaluated a modified protocol for the rapid identification of clinical yeast isolates using matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) technology. First, we evaluated a simplified extraction procedure using 54 clinical yeast isolates. Second, we validated a new protocol with this simplified extraction procedure and lower identification threshold by analysing 167 isolates with either MALDI-TOF or conventional identification techniques. MALDI-TOF analysis with both the standard and short extraction procedure yielded identical identification results, although the log-scores were lower with the latter. With the modified protocol, 163/167 (97.6%) isolates showed a correct identification as compared to conventional identification techniques. A total of 135 out of the 163 (82.8%) correct identifications showed log-scores above 1.7, which we considered as the minimum log-score for secure species identification. The rapid identification of clinical yeast isolates is crucial in patient management. The MALDI-TOF technique using a short extraction procedure can be an alternative for the labourious standard procedure, although the log-scores will be lower. The identification of clinical yeast isolates with the modified protocol is a practical and accurate alternative for conventional identification techniques. If the isolate shows a log-score below 1.7, the standard extraction procedure should be used.