Improved DNA extraction and purification with magnetic nanoparticles for the detection of methicillin-resistant Staphylococcus aureus.

Molecular methods offer fast, safe and cost-efficient detection of pathogenic bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). These tests depend on a rapid extraction of bacterial DNA. The aim of this study was to compare an optimized DNA extraction and purification protocol for MRSA using magnetic nanoparticles with the original method. The purity of the extracted DNA was assessed by photometric measurements and the amount of DNA was determined by real-time PCR. Three MRSA reference strains (S. aureus ATCC® 70699, S. aureus ATCC® 43300; S. aureus ATCC® 33592) and eleven MRSA field strains, which include SCCmec elements of types I to XI, were used in this study. The optimized protocol can save approximately 20 min time compared to the original method and the DNA yield was higher with the new protocol. Therefore, this new protocol allows a faster DNA extraction from MRSA cultures.