The study investigates the dissemination of new methicillin-resistant Staphylococcus aureus (MRSA) clones in the community. It identifies multiple MRSA clones carrying type IV staphylococcal cassette chromosome mec (SCCmec) in community-acquired MRSA (C-MRSA) strains from the United States and Australia. These clones grow faster than health-care-associated MRSA (H-MRSA) and are resistant to fewer non-beta-lactam antibiotics. The C-MRSA strains are derived from more diverse S. aureus populations than H-MRSA strains. The study uses multiple locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) to analyze the genetic backgrounds of the C-MRSA/NORSA strains, which show a distinct clonal distribution from H-MRSA. The presence of type IV SCCmec in C-MRSA strains is noted, which lacks antibiotic resistance genes other than mecA, contributing to their non-multiresistant nature. The findings suggest that these new MRSA clones are emerging and expanding in the community, distinct from major H-MRSA clones.The study investigates the dissemination of new methicillin-resistant Staphylococcus aureus (MRSA) clones in the community. It identifies multiple MRSA clones carrying type IV staphylococcal cassette chromosome mec (SCCmec) in community-acquired MRSA (C-MRSA) strains from the United States and Australia. These clones grow faster than health-care-associated MRSA (H-MRSA) and are resistant to fewer non-beta-lactam antibiotics. The C-MRSA strains are derived from more diverse S. aureus populations than H-MRSA strains. The study uses multiple locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) to analyze the genetic backgrounds of the C-MRSA/NORSA strains, which show a distinct clonal distribution from H-MRSA. The presence of type IV SCCmec in C-MRSA strains is noted, which lacks antibiotic resistance genes other than mecA, contributing to their non-multiresistant nature. The findings suggest that these new MRSA clones are emerging and expanding in the community, distinct from major H-MRSA clones.