Bordetella Species Detection Using Multiplex Real-Time PCR
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Solution Overview
Problem
Current methods for diagnosing whooping cough, caused by Bordetella species, are slow, prone to false negatives, and struggle to differentiate between related species like B. pertussis, B. parapertussis, and B. holmesii, leading to challenges in timely and accurate treatment selection.
Innovation Solution
A method using real-time PCR with specific primer pairs for IS481, IS1001, and hIS1001 target nucleic acids to rapidly detect and discriminate between B. pertussis, B. parapertussis, and B. holmesii in a biological sample without prior extraction, allowing for direct sample-to-result analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bacterial cultures are used to diagnose whooping cough, then conclusive positive results are obtained, but the diagnosis requires 5 to 7 days and is prone to false negative results
Solution Approach 1:
The patent replaces the traditional mechanical bacterial culture system with a molecular biology-based PCR detection system. This substitution enables rapid amplification and detection of Bordetella DNA sequences, reducing diagnosis time from 5-7 days to a matter of hours while maintaining high diagnostic accuracy through specific primer-targeted detection.
Solution Approach 2:
The patent performs preliminary extraction and concentration of Bordetella DNA from clinical samples before PCR amplification. This preliminary action prepares the sample in advance with sufficient target DNA concentration, enabling rapid subsequent amplification and detection, thus reducing the overall diagnosis time while ensuring reliable results.
2Reliability
If antibody assays are used to detect Bordetella infection, then good sensitivity and specificity are achieved, but the assays require blood samples and are limited to early and/or convalescent stages
Solution Approach 1:
The patent extracts and detects Bordetella-specific DNA sequences directly from respiratory tract samples such as nasopharyngeal swabs. This extraction approach eliminates the need for blood sampling required by antibody assays, making the test easier to perform and applicable across all disease stages rather than being limited to early or convalescent phases.
Solution Approach 2:
The patent uses Bordetella-specific DNA sequences as an intermediary marker for detection. Instead of detecting antibodies that require blood samples and specific disease stages, the DNA-based intermediary marker can be directly extracted from respiratory samples, enabling universal application across all infection stages with equivalent sensitivity and specificity.
3Speed
If direct fluorescent antibody testing is used, then rapid detection is possible, but the method lacks sensitivity
Solution Approach 1:
The patent merges the speed advantage of direct detection methods with the sensitivity advantage of amplification techniques by combining rapid sample processing with PCR amplification. This integration maintains the quick turnaround of direct testing while achieving the high sensitivity of molecular methods, overcoming the sensitivity limitation of direct fluorescent antibody testing.
Solution Approach 2:
The patent changes the detection parameter from antibody-antigen binding (less sensitive) to DNA sequence amplification (highly sensitive). By detecting and amplifying specific Bordetella DNA sequences rather than relying on fluorescent antibody binding, the method achieves both rapid detection and high sensitivity, resolving the contradiction between speed and reliability.
4Device complexity
If single-species detection methods are used, then simple procedures are maintained, but the ability to differentiate between related Bordetella species is lost
Solution Approach 1:
The patent segments the detection process into multiple specific PCR reactions, each targeting species-specific DNA sequences of different Bordetella species. This segmentation allows simultaneous differentiation of B. pertussis, B. parapertussis, and B. holmesii in a single sample while maintaining relatively simple procedural steps, preserving species identification accuracy without excessive complexity.
Solution Approach 2:
The patent creates a universal multiplex PCR system that can detect and differentiate multiple Bordetella species simultaneously using a single integrated assay. This multi-functional approach maintains procedural simplicity comparable to single-species testing while providing comprehensive species identification, preventing loss of differentiation information.
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, sensitive, and simultaneous detection of multiple Bordetella species, facilitating prompt therapeutic regimen selection based on accurate species identification.
Implementation Method 1
contacting the biological sample with: (i) a first primer pair that amplifies an IS481 target nucleic acid, (ii) a second primer pair that amplifies an IS1001 target nucleic acid, and (iii) a third primer pair that amplifies a hIS1001 target nucleic acid
Implementation Method 2
subjecting the reaction-sample mixture to real-time PCR conditions under which each of the target nucleic acids present in the biological sample is amplified to produce a fluorescent signal
Data Source
AI summary
The present disclosure provides methods for determining whether a patient exhibiting pertussis-like symptoms will benefit from treatment, with therapeutic agents that inhibit Bordetella holmesii. These methods are based on detecting Bordetella pertussis, Bordetella parapertussis, and Bordetella holmesii in a biological sample by assaying for the presence of the IS481, IS 1001, and hIS1001 target repeat elements, respectively. Kits for use in practicing the methods are also provided.