Method For Using Protein Databases To Identify Microorganisms

摘要

A method for identifying microorganisms by MALDI-TOF mass spectrometry includes acquiring a MALDI mass spectrum of a microorganism, detecting peaks in the acquired MALDI spectrum, generating a peak list comprising mass and intensity from the detected peaks in the acquired MALDI spectrum, acquiring a database of protein sequences deduced from DNA sequences for microorganisms, generating a sub-database of ribosomal proteins from the protein sequences and their masses in the database, matching masses of the detected peaks in the acquired MALDI spectrum to masses of the ribosomal proteins in the generated sub-database, scoring the matches obtained above for each represented microorganism, generating a peak list of accurate masses of matched ribosomal proteins, recalibrating the peak list comprising mass and intensity with the peak list of accurate masses of matched ribosomal proteins, identifying a microorganism with the highest score, and repeating until a desired improvement in the recalibrated peak list or a validated identification is achieved.

主权项

1. A method for identifying microorganisms by MALDI-TOF mass spectrometry, the method comprising:
a) acquiring a MALDI mass spectrum of a microorganism; b) detecting peaks in the acquired MALDI spectrum; c) generating a peak list comprising mass and intensity from the detected peaks in the acquired MALDI spectrum; d) acquiring a database of protein sequences deduced from DNA sequences for microorganisms with a computer; e) generating with a computer a sub-database of ribosomal proteins from the protein sequences and their masses in the database; f) matching masses of the detected peaks in the acquired MALDI spectrum to masses of the ribosomal proteins in the generated sub-database with a computer; g) scoring the matches between the masses of the detected peaks in the acquired MALDI spectrum and the ribosomal proteins in the generated sub-database for each represented microorganism according to a percentage of intensity in the peak list that is matched (% I), a percentage of ribosomal proteins that can be accounted for (% R), and an intensity-weighted average mass error (ppm) for the matches to produce a score; h) generating a peak list of accurate masses of matched ribosomal proteins in step g); i) recalibrating the peak list comprising mass and intensity with the peak list of accurate masses of matched ribosomal proteins generated in step h); j) identifying a microorganism with a highest score by sorting the scores using a computer; and k) repeating steps f through j until a desired improvement in the recalibrated peak list or a validated identification is achieved.