Tn4201, a beta-lactamase transposon in Staphylococcus aureus.

We report the preliminary characterization of a 6.7-kilobase transposon, Tn4201, encoding resistance to penicillin associated with the conjugative plasmid pCRG1600 in Staphylococcus aureus. Tn4201 is capable of inverting in orientation (frequently observed in derivatives of pCRG1600) and is expressed equally well in either orientation. The element is also capable of movement to alternative plasmid and chromosomal sites. Tn4201 exhibits rec-independent transposition in an apparent site-specific manner and may play an important role in the resistance of staphylococci to beta-lactam compounds.