Allelic Discrimination Assays for MRSA Strain Identification
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Solution Overview
Problem
Current methods for identifying and differentiating Methicillin-resistant Staphylococcus aureus (MRSA) strains, such as USA100, USA300, and USA600, are limited by their accuracy, reproducibility, technical complexity, and cost, making it difficult to rapidly and effectively identify sources of infection and implement interventions in healthcare settings.
Innovation Solution
The development of specific primer sets and probes, designed to target strain-specific SNPs, allows for the rapid identification and differentiation of MRSA strains through real-time PCR assays, using sequences such as those represented by SEQ ID NOs. 9-24, which are added to a reaction mixture to amplify and label nucleic acid products, enabling accurate allelic identification of MRSA strains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulsed-field gel electrophoresis (PFGE) is used for MRSA strain typing, then strain identification can be performed, but many isolates are indistinguishable and the method lacks accuracy for differentiating specific strains
Solution Approach 1:
The patent segments the MRSA strain identification process by targeting specific genetic loci (spa, nuc, coa, femA, clfA, clfB, smpA, smpB, smpC, smpD, smpE, smpF, smpG, smpH, smpI, smpJ, smpK, smpL, smpM, smpN, smpO, smpP, smpQ, smpR, smpS, smpT, smpU, smpV, smpW, smpX, smpY, smpZ) with strain-specific primers and probes. This segmentation allows differentiation of strains that appear identical through whole-genome methods like PFGE, thereby improving measurement precision and reliability of strain typing.
Solution Approach 2:
The patent applies local quality by designing primers and probes that target specific local regions (genetic loci) within the MRSA genome that exhibit strain-specific variations. Rather than analyzing the entire genome uniformly, the method focuses on specific high-value regions that provide discriminatory power for strain differentiation, improving both accuracy and reproducibility.
2Measurement precision
If standard microbiological identification systems are used, then genus and species identification can be achieved, but strain-level identification lacks speed and accuracy
Solution Approach 1:
The patent employs preliminary action by pre-designing and storing sequences of multiple genetic loci for various MRSA strains before analysis. These pre-characterized sequences are used to create strain-specific primers and probes in advance, allowing rapid real-time PCR-based identification without time-consuming culture and phenotypic testing, thus improving both accuracy and speed of strain typing.
Solution Approach 2:
The patent replaces traditional mechanical and phenotypic identification methods with molecular biology-based real-time PCR technology. This substitution enables direct detection of strain-specific genetic markers from clinical samples, eliminating the need for prolonged culturing and manual typing procedures, thereby significantly improving identification speed and precision.
3Loss of information
If PFGE typing is performed to identify outbreak strains, then clonal relationships can be understood, but the method is technically complex and time-consuming
Solution Approach 1:
The patent extracts and analyzes specific informative genetic loci from the complex MRSA genome, focusing only on the regions that provide outbreak-tracing information. By extracting and amplifying only these relevant segments using strain-specific primers and probes, the method simplifies the analytical process while retaining the ability to identify clonal relationships and outbreak sources, reducing both technical complexity and time requirements.
Solution Approach 2:
The patent changes the parameters of strain identification by shifting from whole-genome analysis (PFGE) to targeted analysis of specific genetic loci with known variability among strains. This parameter change enables the use of real-time PCR with quantitative measurement, simplifying the methodology while improving speed and precision for outbreak investigation.
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 provides a highly sensitive and specific method for typing MRSA strains, improving the ability to rapidly identify infected individuals and implement effective interventions by accurately differentiating between USA100, USA300, and USA600 strains, thereby enhancing infection control measures.
Implementation Method 1
The development of specific primer sets and probes, designed to target strain-specific SNPs, allows for the rapid identification and differentiation of MRSA strains through real-time PCR assays
Implementation Method 2
using sequences such as those represented by SEQ ID NOs. 9-24, which are added to a reaction mixture to amplify and label nucleic acid products, enabling accurate allelic identification of MRSA strains
Data Source
AI summary
The present invention provides assays, methods and kits that may be used to detect and differentiate MRSA isolates, e.g., USA100, USA300 and USA600 strains.