Cobra Probes for tcdC Δ117 Deletion Detection

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Solution Overview

Problem

Current methods for detecting the single-base deletion at nucleotide position 117 in the tcdC gene of Clostridium difficile, particularly in hypervirulent Ribotype 027 strains, face challenges with sensitivity and specificity, leading to potential false positives and false negatives.

Innovation Solution

The use of Cobra probes, which are labeled with a detectable signal and have two domains separated by a linker section, allows for specific detection of the tcdC Δ117 deletion through amplification and hybridization steps, utilizing fluorescently-labeled probes for real-time PCR to identify the presence or absence of the deletion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional detection methods are used for tcdC Δ117, then the detection process is simpler, but the sensitivity and specificity are reduced leading to false positives and false negatives

Engineering Contradiction:
Improvedetection sensitivity and specificityVSAvoiddetection method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection method is segmented into distinct functional components: Cobra probes with specific binding sequences for the deletion site, fluorescent labeling systems, and stepwise detection protocols. This segmentation allows each component to be optimized independently for sensitivity and specificity while maintaining overall method manageability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fluorescently-labeled Cobra probes serve as intermediaries that specifically bind to the tcdC Δ117 deletion sequence, enabling indirect detection through fluorescence signal. This intermediary approach enhances detection precision by providing a measurable signal that directly indicates the presence of the specific genetic marker

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional probes are used, then the detection method is less complex, but false positive and false negative results increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidprobe structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The Cobra probes are designed with local quality enhancement through fluorescent labeling at specific positions and sequences targeted precisely at the deletion site. This localized optimization ensures high reliability by concentrating detection capability exactly where the genetic marker is present, reducing false results

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The detection system uses composite probe structures combining nucleic acid sequences with fluorescent molecules. This composite approach enhances reliability by integrating specific binding capability with detectable signal generation in a single probe molecule

Inventive Principle:
Principle #40Composite materials

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

This approach enhances the sensitivity and specificity of detecting tcdC Δ117, reducing false results and providing a reliable method for diagnosing the presence of epidemic ribotypes of C. difficile, thereby improving clinical diagnostics.

Implementation Method 1

The first domain is a 5' reporter sequence that is designed to be complementary to the region of a target nucleic acid that contains the gene variation or mutation

Methodology Applied
Scientific EffectHybridization:

Implementation Method 2

Cobra probes are labeled with a detectable signal and have two domains separated by a linker section

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3559273B1Cobra probes to detect a marker for epidemic ribotypes of clostridium difficile
Publication Date: 2022.07.13 ROCHE DIAGNOSTICS GMBH
  • EP3559273B1 patent drawingFigure 1
  • EP3559273B1 patent drawingFigure 2
  • EP3559273B1 patent drawingFigure 3

AI summary

Methods for the rapid detection of the presence or absence of a single-base deletion in the tcdC gene of Clostridium difficile in a biological or non-biological sample are described. The methods can include performing an amplifying step, a hybridizing step, and a detecting step. Furthermore, primers, probes, and kits are provided that are designed for the detection of the single-base deletion.