Friday, February 13, 2009
15 Minute MRSA Test
Filed under: Critical Care
, Medicine
TwistDx, a firm out of Cambridge, England, has developed a test to screen for presence of MRSA in nasal mucosa. Requiring only fifteen minutes to provide accurate results, the company's proprietary technology, called recombinase polymerase amplification (RPA), comes in a battery powered device the size of a book.
The Engineer reports:
'We amplify DNA in a fashion that is somewhat similar to PCR,' he said. 'We use these small synthetic pieces of DNA that will target themselves to their matching sequences in the sample if it is present, and lead to DNA synthesis and the doubling of the target DNA from two to four to eight.'The important difference is that we do not use cycles of thermal melting and annealing of the DNA substrates to achieve this amplification cycle.'
Instead, TwistDx uses RPA. Recombinases are enzymes that physically bind to the synthetic pieces of DNA and then search for identical sequences in double-stranded DNA. The process is very similar to those that happen naturally within living cells to match up identical sequences.
When the enzymes find identical sequences, they will then place a synthetic piece opposite its target and allow DNA synthesis.
The system will still require a detector to determine whether a reaction occurred. The TwistDx method includes a biochemical system that releases fluorescent light if DNA amplification and synthesis occurs in a sample. LED-driven sensors that are embedded within the TwistDx device measure the fluorescence.
More at the The Engineer...
TwistDx technology page: RPA (Recombinase Polymerase Amplification)
Image: Clusters of methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Scanning electron micrograph 2008 Collection: Medical Photographic Library Credit: Wellcome Images
(1) examples: <b>Bold</b> <i>Italic</i>
