Subtyping of MRSA isolates belonging to a widely disseminated clonal groupby polymorphism of the dru sequences in mec-associated DNA

During the past 7 years the "Berlin epidemic MRSA" has spread throughout wh ole Germany. SmaI macrorestriction patterns of this clonal group are rather stable as are the length polymorphisms at the 3 ' end of the coagulase gen e and the x-region of spa. However, the dru region (direct repeat units) of mec-associated DNA exhibits a length polymorphism due to deletion of one o r more direct repeat units. Five different subclones could be discriminated by dl M region length polymorphism. Location of deletions and of a few poi nt mutations allow a delineation of these subclones.