The current application of mass spectrometry in microbial testing is time-of-flight mass spectrometry.
The principle is: the laser excites the bacteria and matrix on the target plate so that the bacterial proteins are in the vacuum flight tube. The detector builds a curve pattern by detecting the difference in protein flight time and then compares it with the information in the database to obtain the possible bacterial species.
Interpretation of results: The mass spectrometers currently used in microbiology laboratories are all of this type. The results are generally listed according to the system comparison and the score. Generally, the one with the highest score is the most likely (but the score must be 1.5/1.6) Only the above can be used, and the scoring rules are international standards).
Take the two products currently on the market produced by BD Bruker and Mérieux as examples. :BD recommended rating is 2.0. Mérieux, like most experts in the world, uses 1.8. (The higher the score, the stronger the credibility.)
The quality of the mass spectrometry results is also related to the number of databases and resolution... (Currently, BD completely overwhelms Mérieux’s products in these two aspects)
Advantages and disadvantages of mass spectrometry:
Advantages: simple operation, short experimental time, greatly shortening the time for first-level reports time. (The data given by BD is that the whole process takes 20 minutes, and is consistent with the actual operation results.)
Disadvantages: Mass spectrometry is ultimately the detected protein profile. So things like large intestine and Shiga...these are not easy to identify.
Other aspects: Therefore, the equipment is extremely expensive, and more attention should be paid to the cost of hardware consumables and conventional consumables when the equipment is in use.