WGA and Vancomycin Dual-Fluorescence Gram-Status Detection

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Solution Overview

Problem

Existing methods for distinguishing Gram-positive and Gram-negative bacteria in complex samples, such as human or animal microbiota, are time-consuming and prone to variable results due to the non-specific binding of wheat germ agglutinin (WGA) and lack precision in identifying resistant bacteria, leading to incorrect interpretations.

Innovation Solution

A method using wheat lectin (WGA) coupled with vancomycin, each labeled with different fluorochromes, and optionally potassium chloride, to accurately discriminate and identify Gram-positive and Gram-negative bacteria through flow cytometry by analyzing the relative fluorescence of these markers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional Gram staining techniques are used, then bacterial Gram status can be identified, but the process is time-consuming and results are variable due to non-specific binding and multiple processing steps

Engineering Contradiction:

ImproveGram status identification accuracyVSAvoidAnalysis time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The invention extracts and isolates the specific binding interactions needed for Gram status detection by using fluorescently labeled WGA and vancomycin that directly bind to bacterial cell walls, eliminating the need for multiple staining, rinsing, and processing steps required by conventional Gram staining methods

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical and chemical processing system of conventional Gram staining (fixation, staining, rinsing, drying) with a fluorescent labeling system where specific molecular bindings (WGA to N-acetylglucosamine, vancomycin to peptidoglycan) directly indicate Gram status through fluorescence detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If WGA is used alone for labeling, then Gram-positive bacteria can be targeted, but specificity is reduced due to non-specific binding leading to incorrect interpretations

Engineering Contradiction:

ImproveBacterial targeting capabilityVSAvoidBinding specificity

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention segments the bacterial detection process into two distinct fluorescent channels: WGA fluorescence for Gram-positive bacteria and vancomycin fluorescence for Gram-negative bacteria, allowing independent optimization and verification of each binding interaction's specificity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces vancomycin as an intermediary marker that binds to Gram-negative bacteria, creating a reference population that validates the specificity of WGA binding to Gram-positive bacteria and enables discrimination against non-specific binding events

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If dual-fluorochrome labeling with WGA and vancomycin is used, then discrimination accuracy between Gram-positive and Gram-negative bacteria is improved, but device complexity increases

Engineering Contradiction:

ImproveBacterial discrimination accuracyVSAvoidFlow cytometry setup complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention uses a universal flow cytometry platform that can detect multiple fluorochromes simultaneously, making the dual-labeling system compatible with existing instrumentation and allowing the same device to perform both Gram status determination and bacterial counting functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 precise differentiation of Gram-positive and Gram-negative bacteria, including identification of specific families, genera, and species, within complex samples, regardless of bacterial viability or oxygen requirements, with results obtained in under 40 minutes.

Implementation Method 1

wheat lectin (wheat germ agglutinin (WGA)) coupled to a fluorochrome

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

wheat lectin (wheat germ agglutinin (WGA))

Methodology Applied

Scientific EffectLectin binding: Adsorption

Implementation Method 3

vancomycin coupled to a fluorochrome emitting a fluorescence at a different wavelength

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 4

antibiotic—vancomycin—coupled to a fluorochrome

Methodology Applied

Scientific EffectAntibiotic binding: Adsorption

Implementation Method 5

measuring the fluorescence of the sample

Methodology Applied

Scientific EffectFluorescence detection: Fluorescence

Data Source

PatentUS12455285B2Method for detecting bacteria according to the gram signal thereof in a complex sample

Publication Date: 2025.10.28 MAAT PHARMA

AI summary

The invention relates to a method for detecting the proportion of Gram-positive and Gram-negative bacteria in a complex sample. The bacteria are detected according to the Gram signal thereof. The invention enables distinction between species of Gram-positive bacteria and species of Gram-negative bacteria in a complex sample. The invention also relates to a kit for marking Gram-positive and Gram-negative bacteria, particularly for use in flow cytometry, particularly for complex samples such as human or animal microbiota samples.