Identification of microorganisms using MALDI-TOF-MS on-plate extraction

摘要

Rapid methods that identify sepsis-causing bacteria or yeast aid the physician in critical therapeutic decision-making, thus decreasing patient mortality rates. The methods described herein employ plating microorganisms directly on to a MALDI-MS plate, adding concentrated formic acid, and identifying the microorganism by mass spectrometry. Optionally, an organic solvent may be combined with the formic acid, or added to the sample before or after the concentrated formic acid is added thereto. The methods enable direct extraction of proteins from microorganisms without the need for liquid protein extraction methods and yields positive identification results for gram-positive bacteria, gram-negative bacteria and yeast in minutes.

主权项

1. A method for characterizing at least one microorganism in a sample for identification of microorganisms therein, the method comprising:
(a) obtaining a sample containing at least one microorganism, wherein the sample is in a suspension; (b) depositing at least a portion of the obtained sample on a solid surface adapted to be placed in an apparatus configured to determine the identity of microorganisms by mass spectrometry; (c) drying the deposited sample; (d) treating the deposited and dried sample with a volatile acid solution, wherein the volume percent of the volatile acid is at least 70% of the volatile acid solution combined with the sample, and the volatile acid solution is a volatile acid in water or a volatile solution in an organic solvent; (e) drying the treated sample; (f) placing a matrix over the treated and dried sample; and (g) identifying the microorganisms by a mass spectrometry.