Panton-Valentine Leukocidin–Positive MRSA, Shanghai

We determined the agr type, multilocus sequence type, protein A gene type (spa typing), toxin gene profile, and antimicrobial drug resistance profile of 469 isolates of Panton-Valentine leukocidin-positive community-acquired methicillin-resistant Staphylococcus aureus isolates (PVLpositive CA-MRSA).The isolates had been collected from around the world from 1999 through 2005 by the French National Reference Center for Staphylococci.We found that some continent-specific clones described in 2003, such as clone ST8, have now spread all over the world.Likewise, some PVL-positive CA-MRSA have spread to several countries on various continents.New clones have emerged (e.g., ST377) on new genetic backgrounds.PVLpositive CA-MRSA that were usually susceptible to most antistaphylococcal antimicrobial agents have acquired new resistance determinants (e.g., to gentamicin) in certain countries.The major trait shared by all these clones is a short staphylococcal chromosomal cassette mec element of type IV or V.