Multiplex PCR Assay for Differential MAC Detection

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Solution Overview

Problem

Current methods for detecting Mycobacterium avium complex (MAC) organisms, particularly distinguishing between non-MAP and MAP species, face challenges due to inconsistent classification and the presence of false positives, which complicates differential identification and diagnosis in mammalian host species.

Innovation Solution

The development of specific nucleic acid target sequences and oligonucleotide primers and probes that are unique to non-MAP organisms, such as MAA, MAH, and MAS, allowing for differential detection and exclusion of MAP organisms through nucleic acid amplification and hybridization methods, providing a one-step diagnostic approach.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional detection methods are used to identify MAC organisms, then detection coverage is achieved, but false positives occur due to inability to distinguish between non-MAP and MAP species

Engineering Contradiction:
Improvedetection accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection method is segmented into two distinct parts: a first set of primers that amplifies a common MAC region present in all Mycobacterium avium subspecies, and a second set of primers that amplifies a subspecies-specific region unique to non-MAP organisms. This segmentation allows the assay to first confirm MAC presence and then specifically identify non-MAP subspecies, eliminating false positives from MAP organisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by targeting specific genomic regions with different properties: a conserved region for general MAC detection and a variable region for subspecies differentiation. The second primer set is designed to bind only to the specific nucleotide sequence found in non-MAP organisms, providing localized specificity within the broader MAC detection framework.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If subspecies classification is based on infection species rather than nucleic acid sequence, then classification can be performed without genomic data, but classification becomes inconsistent and complicated

Engineering Contradiction:
Improveclassification simplicityVSAvoidclassification consistency
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention replaces the mechanical/biological observation method (identifying subspecies based on which species they infect) with a molecular/nucleic acid-based method. By substituting the classification mechanism from phenotypic observation to genotypic analysis, the method achieves both ease of application (simple PCR-based detection) and precision (consistent nucleic acid sequence-based classification).

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

3Adaptability or versatility

If multiple separate assays are used to detect different MAC subspecies, then comprehensive detection is achieved, but diagnostic complexity and time increase

Engineering Contradiction:
Improvedetection coverageVSAvoidassay complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges the functionality of multiple separate detection assays into a single multiplex PCR assay. By combining the first primer set (detecting all MAC organisms) and the second primer set (detecting only non-MAP organisms) in one reaction, the method achieves comprehensive subspecies differentiation while simplifying the diagnostic process to a single test rather than multiple sequential assays.

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

This solution enables specific and sensitive detection of non-MAP organisms, reducing false positives and improving diagnostic accuracy, facilitating rapid and precise identification in various mammalian host species.

Implementation Method 1

oligonucleotide primers and probes that are unique to non-MAP organisms, allowing for differential detection and exclusion of MAP organisms through nucleic acid amplification and hybridization methods

Methodology Applied
Scientific EffectHybridization:

Implementation Method 2

differential detection and exclusion of MAP organisms through nucleic acid amplification and hybridization methods

Methodology Applied
Scientific EffectNucleic acid amplification:

Data Source

PatentEP2839025B1Compositions and methods for detection of microorganisms of the mycobacterium avium complex excluding mycobacterium avium paratuberculosis
Publication Date: 2017.04.19 LIFE TECHNOLOGIES CORP
  • EP2839025B1 patent drawingFigure 1
  • EP2839025B1 patent drawingFigure 2
  • EP2839025B1 patent drawingFigure 3

AI summary

Disclosed are compositions, assays, methods, diagnostic methods, kits and diagnostic kits for the specific and differential detection of a non-Mycobacterium avium subsp. paratuberculosis (non-MAP) organism, wherein a non-MAP organism is a Mycobacterium avium complex (MAC) organism that does not belong to the Mycobacterium avium subsp. paratuberculosis (MAP) organism, from samples including veterinary samples, clinical samples, food samples, forensic sample, an environmental sample (e.g., soil, dirt, garbage, sewage, air, or water), including food processing and manufacturing surfaces, or a biological sample. Exemplary non-MAP organisms including M. avium subsp. avium (MAA), M. avium subsp. hominissuis (MAH), and M. avium subsp. silvaticum (MAS) can be detected by the present compositions, kits and methods.