Mass Spectrometry GAS Emm Typing with Diagnostic m/z Peaks

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Solution Overview

Problem

Existing methods, such as NPTL1, fail to accurately identify the emm type of Group A Streptococcus (GAS) using mass spectrometry, particularly for invasive and noninvasive infections, which is crucial for diagnosing and treating conditions like Streptococcal toxic shock syndrome (STSS).

Innovation Solution

An analysis method utilizing mass spectrometry to identify Group A Streptococcus emm types 1 and 12 by detecting peaks in specific m/z ranges (10930-10945 for emm type 1 and 6908-6918 for emm type 12) in the mass spectrum, using matrix-assisted laser desorption/ionization with sinapic acid or CHCA as the matrix.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If mass spectrometry is used to identify GAS emm types, then identification speed is improved, but identification accuracy deteriorates (cannot distinguish emm types)

Engineering Contradiction:

Improveidentification speedVSAvoidemm type identification accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The mass spectrum is segmented into specific m/z range regions (first range: 10930-10945, second range: 6908-6918) to detect characteristic peaks corresponding to different emm types. By focusing on specific spectral segments rather than analyzing the entire spectrum, the method achieves both rapid identification and accurate emm type distinction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The method assigns different diagnostic weights to different m/z regions: the first range (10930-10945) is associated with emm type 1, while the second range (6908-6918) is associated with emm type 12. This local differentiation of spectral regions enables accurate emm type identification based on the presence or absence of peaks in specific local areas of the mass spectrum.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If PCR-based sequencing is used to identify emm types, then identification accuracy is improved, but analysis time increases

Engineering Contradiction:

Improveemm type identification accuracyVSAvoidanalysis time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/chemical PCR amplification and sequencing process with a direct mass spectrometry-based detection method. Instead of amplifying and sequencing DNA, the method directly detects characteristic mass spectral peaks corresponding to emm types, eliminating the time-consuming PCR steps while maintaining identification accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The method performs preliminary characterization of GAS emm types through mass spectrometry before any further analysis or treatment decisions are needed. By obtaining emm type information directly from the mass spectrum without requiring prior DNA extraction and amplification, the analysis time is significantly reduced while maintaining diagnostic accuracy.

Inventive Principle:

Principle #10Preliminary action

3Loss of time

If mass spectrometry without PCR is used, then analysis time is reduced, but emm type identification capability is lost

Engineering Contradiction:

Improveanalysis timeVSAvoidemm type information

Core Design Contradiction:

Loss of timeVSLoss of information

Solution Approach 1:

The mass spectrum serves as an intermediary carrier that contains encoded information about emm types. By detecting specific peaks in the mass spectrum (first range for emm type 1, second range for emm type 12), the method recovers emm type information without requiring PCR amplification, thus avoiding time loss while preventing information loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The method changes the detection parameter from DNA sequence composition (requiring PCR) to mass-to-charge ratio (m/z) characteristics. By detecting peaks at specific m/z values (10930-10945 for emm type 1, 6908-6918 for emm type 12), the method obtains emm type information directly from mass spectral data without needing to amplify DNA, thus reducing analysis time while maintaining information accuracy.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables rapid and accurate identification of emm types 1 and 12 without PCR, facilitating timely diagnosis and treatment of GAS infections.

Implementation Method 1

in the mass spectrometry, the sample is ionized by matrix-assisted laser desorption/ionization, using sinapic acid or CHCA as a matrix

Methodology Applied

Scientific EffectMatrix-assisted laser desorption/ionization: Laser Ablation

Data Source

PatentUS12379382B2Analysis method, analytical method and microorganism identification method

Publication Date: 2025.08.05 SHIMADZU CORP

AI summary

An analysis method includes: acquiring data corresponding to a mass spectrum obtained by subjecting a sample containing a microorganism to mass spectrometry; and acquiring information on Group A Streptococcus of emm type 1, based on the presence or absence, or magnitude of a peak in a first range of m/z of 10930 or more to 10945 or less in the mass spectrum.