Improvement in bacterial strain differentiation by MALDI-TOF MS profiling by using microwave-assisted enzymatic digestion

摘要

MALDI-TOF MS profiling is routinely used in microbiology for identification of bacteria on the basis of their peptide/ protein profiles. However, the discriminatory power of the method is not always sufficient in certain caseswhich require distinguishing of individual strains, as closely related strains can yield very similar MALDI-TOF mass spectra. Strains of Staphylococcus aureus, Staphylococcus haemolyticus, and Bacillus subtilis (two ecotypes) were subjected to standard sample preparation procedure involving formic acid/acetonitrile extraction and intact protein profiling by MALDI-TOF MS. As a novel method variant, the bacterial cells were digested by trypsin under microwave irradiation for 2 min prior to the MALDI-TOF MS profiling. The evaluation of the discriminatory power of the method was carried out on the basis of cluster analysis.