SNP-Based Staphylococcus aureus Lineage Typing via Real-Time PCR
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Solution Overview
Problem
Current methods for typing Staphylococcus aureus, particularly within clonal complex 8 (CC8), are imprecise and lack consistency, leading to confusion in strain nomenclature and challenging surveillance and infection control due to the limitations of pulse field gel electrophoresis (PFGE) and spa typing, which fail to distinguish between lineages effectively.
Innovation Solution
A canSNP-based approach using real-time PCR assays with specific probes targeting canonical single nucleotide polymorphisms (SNPs) to accurately detect and differentiate major lineages of Staphylococcus aureus, including USA300, USA500, and ST239, providing a stable and scalable method for strain typing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse field gel electrophoresis (PFGE) is used for strain typing, then strain types can be determined, but the method is laborious and determination is subjective with heterogeneity in banding patterns
Solution Approach 1:
The patent replaces the mechanical PFGE system with a molecular biology-based PCR typing system. Instead of separating DNA fragments by size through electrophoresis, the invention uses specific PCR primers and probes to detect lineage-specific genetic sequences, eliminating the need for complex gel electrophoresis apparatus and subjective band pattern interpretation.
Solution Approach 2:
The patent uses PCR amplification to create copies of specific genomic regions containing lineage-determining sequences. By amplifying these target regions and detecting them with specific probes, the method creates a simplified representative copy of the strain's genetic identity, avoiding the need to analyze entire genomic profiles through complex electrophoresis.
2Measurement precision
If spa gene sequencing is used for typing, then strain identification can be performed, but it is relatively expensive and spa types aren't always consistent with evolutionary lineages
Solution Approach 1:
The patent extracts only the specific lineage-determining genetic sequences needed for typing, rather than sequencing the entire spa gene or genome. By designing PCR primers and probes that target only the critical discriminatory regions, the method reduces sequencing costs while maintaining typing accuracy for epidemiological purposes.
Solution Approach 2:
The patent applies partial sequencing or targeted detection of specific genomic regions rather than complete spa gene sequencing. By focusing only on the essential lineage-defining sequences, the method achieves sufficient typing precision at a lower cost, performing just enough sequencing to distinguish lineages without unnecessary expense.
3Adaptability or versatility
If PFGE and spa typing are used alone, then basic strain classification can be achieved, but they are not able to distinguish among lineages within CC8
Solution Approach 1:
The patent segments the CC8 complex into distinct lineages (USA300, USA500, Archaic, Iberian, ST239) by targeting specific genetic markers unique to each lineage. Instead of treating CC8 as a single group, the method divides it into resolvable sub-lineages using multiple specific PCR assays, each detecting particular lineage-defining sequences.
Solution Approach 2:
The patent applies local quality by using lineage-specific genetic markers distributed throughout the genome. Different PCR primers and probes target specific local regions (e.g., PVL genes, ACME genes, enterotoxin genes, SCCmec variants) that are characteristic of particular lineages, allowing precise differentiation based on local genetic characteristics rather than whole-genome analysis.
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 SNP-based method offers a rapid, robust, and consistent way to identify Staphylococcus aureus lineages, improving epidemiological investigations and clinical diagnosis by eliminating lineage confusion and enhancing the accuracy of strain characterization.
Implementation Method 1
contacting the nucleic acid or the amplicon with a SNP variant polynucleotide probe; and detecting specific hybridization of the SNP variant probe to the nucleic acid or to the amplicon
Data Source
AI summary
The present invention provides a method of detecting Staphylococcus aureus in a subject, by contacting a sample obtained from the subject with at least one detectably labeled probe of the invention or detecting in the sample identity to a sequence of the invention. The invention is also directed to kits, microarrays and detectable Staphylococcus aureus polynucleotide probes useful in detecting the presence of Staphylococcus aureus.