Effect of ribosomal protein preservation conditions on identification of aspergillus by matrix assisted laser desorption ionization time-of-flight mass spectrometry

Abstract

Objective To investigate the effect of ribosomal protein preservation conditions on the identification of aspergillus by matrix assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF MS, VITEK MS V 3.0). Methods Aspergilli were isolated from the specimens of patients with clinical invasive aspergillus infection and the ribosomal proteins of the aspergilli were extracted and stored under different conditions. Then the proteins under different storage conditions were identified by MALDI-TOF MS and the identification results were compared. Results The identification accuracies at 4℃, -20℃, and -80℃ were 97.73%, 98.01%, and 97.73%, respectively, with no statistical difference (χ2=0.087, P=0.957). The identification accuracies at 48 h, 72 h, 120 h, and 168 h storage times were 97.73%, 97.44%, 98.01%, and 98.01%, with no statistical difference (χ2=0.827, P=0.843). After being stored at 4℃, -20℃, and -80℃ for different times, there was no significant change in the mass spectrum peaks of the identification results. Conclusions Ribosomal proteins used for the identification of Aspergilli by MALDI-TOF MS can stay stable within 7 days and there is no significant change in the mass spectrum peaks of the identification results. Ribosomal protein preservation conditions have no effect on the identification results by MALDI-TOF MS technology. Key words: Matrix assisted laser desorption ionization time-of-flight mass spectrometry; MALDI-TOF MS; Aspergillus; Ribosomal protein