Pulsed-field gel electrophoresis typing of Staphylococcus aureus isolates.

Pulsed-field gel electrophoresis (PFGE) is the most applied and effective genetic typing method for epidemiological studies and investigation of foodborne outbreaks caused by different pathogens, including Staphylococcus aureus. The technique relies on analysis of large DNA fragments generated by the cleavage of intact bacterial chromosomes with a rare cutting restriction enzyme, subsequently resolved by pulsed-field electrophoresis with periodic changes of the orientation of the electrical field across the gel. The high discriminatory power, improved reproducibility due to standardization of experimental protocols and data interpretation guidelines, and establishment of a national PFGE database of S. aureus profiles have made it a valuable means for global tracking of S. aureus infection sources and determination of genetic relatedness of outbreak isolates.