The RM Test for Determining Methicillin-Resistant Staphylococcus aureus Lineages
Staphylococcus aureus lineages evolve independently and differ in hundreds of genes. Identification of lineages can be useful for epidemiological typing and infection control at the local or global level, and can also be useful when investigating differences in pathogenesis between strains. MLST (multilocus sequence typing) and spa typing (polymorphisms in the protein A gene) are useful methods for identifying lineages but can be time-consuming and expensive. Here, we describe a method for identifying lineages using PCR, which is very easy to perform and can generate results within hours. It can also be adapted to commercial or real-time platforms. The RM (restriction modification) test is based on unique sequences found in each lineage that determine the specificity of an RM system, which detects and digests foreign DNA, thereby controlling the independent evolution of the lineages; thus, it is the ideal single gene to target for a rapid lineage test.
Key wordsMethicillin-resistant Staphylococcus aureus MRSA Restriction modification RM test Lineages Typing PCR
We are indebted to Joshua Cockfield who developed these tests, and trained many colleagues in their use. This project was funded by a joint grant to JAL and Jonathan Edgeworth, from the Guy’s and St Thomas’ Hospital Charitable Foundation.
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