Primers and Probes for Toxigenic C. difficile Detection

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Solution Overview

Problem

Current methods for detecting toxigenic strains of Clostridium difficile are time-consuming and lack specificity, particularly in clinical samples, as they rely on tissue culture cytotoxin assays which take at least 24 hours to produce results.

Innovation Solution

Development of primers and probes specifically designed to target the toxin B (TcdB) gene of C. difficile, enabling rapid and specific detection of toxigenic strains through nucleic acid-based amplification methods like PCR, allowing for real-time analysis in clinical samples such as stool or blood.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If tissue culture cytotoxin assays are used to detect toxigenic C. difficile strains, then detection reliability is maintained, but detection time is excessively long (at least 24 hours)

Engineering Contradiction:

Improvedetection timeVSAvoiddetection reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent replaces the mechanical/biological tissue culture system with a nucleic acid amplification system (PCR). Instead of using living cells to detect toxin production, the invention uses primers and probes to amplify and detect specific DNA sequences (tcdA and tcdB genes) that encode the toxins. This substitution of detection methodology reduces time from 24+ hours to a few hours while maintaining reliability through specific genetic targeting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary identification by targeting specific genetic sequences (tcdA and tcdB genes) that are known to be present in toxigenic strains. By detecting the presence of these genes through PCR amplification with specific primers and probes, the method predicts toxin production capability before actual toxin expression occurs in culture, thereby reducing detection time while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If conventional detection methods are used, then broad detection capability is maintained, but measurement precision and specificity are insufficient

Engineering Contradiction:

Improvedetection specificityVSAvoiddetection capability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by designing specific primers and probes that target distinct regions of the tcdA and tcdB genes. Different primer pairs and probes are configured to detect specific toxin types (TcdA, TcdB, or both), allowing precise identification of toxigenic strain characteristics. This localized targeting of specific gene regions enhances detection specificity while maintaining the ability to detect various toxigenic strains.

Inventive Principle:

Principle #3Local quality

3Productivity

If rapid detection methods are implemented, then detection speed increases, but detection accuracy and reliability may deteriorate

Engineering Contradiction:

Improvedetection speedVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces slow biological culture systems with rapid nucleic acid amplification (PCR). The use of thermocycling and enzymatic DNA amplification allows detection within hours rather than days. Specificity is maintained through the use of gene-specific primers and probes that selectively amplify only C. difficile toxin genes, ensuring accurate and rapid identification of toxigenic strains.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces nucleic acid amplification as an intermediary step between sample collection and toxin detection. Instead of directly observing toxin production in culture, the method uses PCR to amplify and detect genetic markers (tcdA and tcdB genes) that serve as reliable intermediaries for predicting toxin production capability, thereby achieving both speed and accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The use of these primers and probes provides a rapid, sensitive, and specific method for detecting toxigenic C. difficile strains, reducing detection time significantly and improving diagnostic accuracy in clinical settings.

Implementation Method 1

primers and probes that bind to the toxin B (TcdB) gene

Methodology Applied

Scientific EffectNucleic acid hybridization:

Implementation Method 2

nucleic acid-based amplification methods using particular primers and probes

Methodology Applied

Scientific EffectNucleic acid amplification:

Data Source

PatentUS9863007B2Detection of toxigenic strains of <i>Clostridium difficile</i>

Publication Date: 2018.01.09 GENEOHM SCI CANADA

AI summary

Primers and probes for detection of toxin-producing (toxigenic) strains of Clostridium difficile, and to methods of detecting toxigenic strains using these primers and probes. Toxigenic strains of C. difficile are detected by nucleic acid-based amplification methods using particular primers and probes that bind to the toxin B (TcdB) gene. These primers and probes are used to amplify C. difficile nucleic acids in clinical samples to determine the presence of these toxigenic strains.