Preparation of ElectrocompetentStaphylococcus aureusCells and Plasmid Transformation

This protocol is part of a series of methodologies for the construction of an in-frame gene deletion in Staphylococcus aureus strain RN4220. Having previously described how an allelic-exchange plasmid containing a desired gene deletion (in this case, pIMAY*-Δ tagO ) can be constructed and isolated from Escherichia coli , we now present details of the next steps in this method—the preparation of electrocompetent S. aureus cells and introduction of the tagO mutant plasmid DNA into the S. aureus cells by electroporation. Colonies containing the plasmid can then be selected on chloramphenicol plates at a low temperature permissive for plasmid replication.