The 46.4-kb nucleotide sequence of pSK41, a prototypical multiresistance plasmid from Staphylococcus aureus, has been determined, representing the first completely sequenced conjugative plasmid from a grampositive organism. Analysis of the sequence has enabled the identification of the probable replication, maintenance, and transfer functions of the plasmid and has provided insights into the evolution of a clinically significant group of plasmids. The basis of deletions commonly associated with pSK41 family plasmids has been investigated, as has the observed insertion site specificity of Tn552-like �-lactamase transposons within them. Several of the resistance determinants carried by pSK41-like plasmids were found to be located on up to four smaller cointegrated plasmids. pSK41 and related plasmids appear to represent a consolidation of antimicrobial resistance functions, collected by a preexisting conjugative plasmid via transposon insertion and IS257-mediated cointegrative capture of other plasmids. Staphylococcus aureus and, increasingly, coagulase-negative staphylococci are significant nosocomial pathogens, largely as a consequence of their propensity to develop antimicrobial resistance (37). Resistance determinants can be chromosomally encoded and/or carried by one or more plasmids commonl
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.