Multiplex Real-Time PCR Assay for Legionella Detection

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Solution Overview

Problem

Current methods for detecting Legionella, such as culture, are time-consuming and impractical for timely diagnosis or surveillance, especially in cases of outbreaks, as they require specific media and expertise, and cannot efficiently identify multiple species simultaneously.

Innovation Solution

The use of multiplex real-time PCR assays with specific probes and primers capable of hybridizing to Legionella nucleic acids under high stringency conditions, allowing for rapid, sensitive, and specific detection and discrimination of Legionella species, including Legionella pneumophila and other relevant species, in clinical and environmental samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If culture method is used for Legionella detection, then identification accuracy is improved, but detection time increases significantly and requires specific media and expertise

Engineering Contradiction:
Improveidentification accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical culture-based detection system with a molecular biology-based PCR system. Specifically, it uses real-time PCR with fluorescent probes to detect Legionella nucleic acids, eliminating the need for prolonged culture periods while maintaining identification accuracy. The method achieves detection within hours rather than weeks by directly amplifying and detecting bacterial DNA/RNA.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from phenotypic observation (culture growth) to genotypic detection (nucleic acid amplification). By targeting specific Legionella gene sequences through PCR, the method achieves rapid identification without requiring the bacteria to be cultured, thus resolving the time-accuracy contradiction.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If culture method is used for Legionella detection, then identification capability is improved, but operational complexity and resource requirements increase

Engineering Contradiction:
Improveidentification capabilityVSAvoidoperational complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex culture media preparation and maintenance requirements with a standardized PCR reaction system. The real-time PCR method uses commercially available reagents and automated thermal cyclers, reducing the need for specialized expertise in media preparation and bacterial culture maintenance while maintaining broad identification capability across Legionella species.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent develops a universal PCR assay system that can detect multiple Legionella species and serogroups using a single set of primers and probes. This multi-functional approach eliminates the need for multiple specialized culture media and techniques, simplifying operational complexity while maintaining versatility in identifying different Legionella pathogens.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If traditional detection methods are used, then detection capability for single species is improved, but ability to detect multiple species simultaneously deteriorates

Engineering Contradiction:
Improvedetection capabilityVSAvoidmulti-species detection capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the detection process into multiple independent probe-target interactions, each specific to a particular Legionella species or serogroup. By using a panel of species-specific fluorescent probes in a single PCR reaction, the method can simultaneously detect and differentiate multiple Legionella species while maintaining the detection precision of individual species-specific assays.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple species-specific detection capabilities into a single multiplex real-time PCR assay. By combining multiple probes with different fluorescent labels in one reaction tube, the system achieves simultaneous detection of multiple Legionella species, resolving the contradiction between precise single-species detection and multi-species detection capability.

Inventive Principle:
Principle #5Merging (Combining)

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 simultaneous detection of multiple Legionella species, including non-pneumophila species, in clinical and environmental samples, providing timely diagnosis and surveillance capabilities, even for non-culturable bacteria or those within protozoan hosts.

Implementation Method 1

contacting a sample with one or more probes capable of hybridizing to a Legionella nucleic acid under high or very high stringency conditions, wherein each of the probes are detectably labeled, and detecting hybridization between one or more of the probes and a nucleic acid

Methodology Applied
Scientific EffectHybridization:

Implementation Method 2

utilizing real-time PCR (such as multiplex real-time PCR)

Methodology Applied
Scientific EffectPCR amplification:

Data Source

PatentEP2859117B1Methods and compositions for detection of legionella
Publication Date: 2017.12.06 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES
  • EP2859117B1 patent drawingFigure 1A
  • EP2859117B1 patent drawingFigure 1B
  • EP2859117B1 patent drawingFigure 1C

AI summary

Methods for detecting Legionella (such as Legionella spp., Legionella pneumophila, Legionella pneumophila serogroup 1, Legionella bozemanii, Legionella dumoffii, Legionella feeleii, Legionella longbeachae, and/or Legionella micdadei) are disclosed. A sample suspected of containing one or more Legionella nucleic acids is screened for the presence or absence of that nucleic acid. Determining whether Legionella nucleic acid is present in the sample can be accomplished by detecting hybridization between a Legionella probe and a nucleic acid in a sample. Also disclosed are probes and primers for the detection of Legionella, and kits that contain the disclosed probes and/or primers.