Genetic differentiation of Candida krusei based on matrix-assisted laser desorption ionization time-of-flight mass spectrometry

ObjectiveTo identify the genetic differentiation characteristics of Candida krusei at the level of protein and establish different lineage identification methods based on matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

MethodsMALDI-TOF MS coupled to ClinProTools was used to discover MALDI-TOF MS biomarker peaks and establish a classification model based on a genetic algorithm (GA) to differentiate the different lineages of C. krusei. Twenty strains of C. krusei were used to establish an analysis model, and 25 strains of were used for the validation.

ResultsFor the GA typing model using 20 strains of C. krusei, the recognition capability (RC) value, which reflects the model’s ability to correctly identify its component spectra was 100%, and the cross-validation (CV) value, which reflects the ability of the model to handle variability among the test spectra was 97.89% and the classification power value of the validation model for 25 C. krusei strains and 150 mass spectrums was 95.30%. This model contained 13 biomarker peaks (m/z 3 971.40, 3 136.95, 3 427.33, 2 405.28, 2 996.73, 2 913.95, 3 376.97, 6 736.13, 5 819.03, 4 045.16, 5 869.00, 3 618.10 and 3 946.14) and can be used to correctly identify different lineages of C. krusei.

ConclusionThis study demonstrated not only the population genetic differentiation of C. krusei from the peptide level, but also confirmed the existence of this event, and more importantly, a simple and effective rapid lineage typing method was established in this study.