Conjugative transfer of high-level mupirocin resistance from Staphylococcus haemolyticus to other staphylococci

A conjugative plasmid, pXU10, encoding high-level mupirocin resistance was transferred from a Staphylococcus haemolyticus isolate, CN216, to other coagulase-negative staphylococci and a restriction deficient Staphylococcus aureus strain, XU21, but not to clinical isolates or a restriction-proficient laboratory strain (strain WBG541) of S. aureus. However, from XU21 it was cotransferred with a 3.5-kb chloramphenicol resistance plasmid to WBG541. The results demonstrated the ability of pXU10 to mobilize nonconjugative plasmids.