Table 2.

Six genetic elements associated with meticillin and fusidic acid resistance.

Cassette	Sequence type	Patient isolates	Closest published homologues
Composite islands (two adjacent SCCs, encoding either fusC or mecA)
SCC476 and SCCmecIVa	ST1	MRSA2, 6, 14, 22	SCC476[24] and SCCmecIVa [22]
SCCmecIVa and SCC149	ST149 + 2942	MRSA1, 4, 5, 13, 15, 17	SCCmecIVa [22] and SCCfusC[25]
Chimeric cassettes (single cassettes encoding both fusC and mecA)
SCCmec-fus I	ST1	MRSA3	N/A
SCCmec-fus II	ST5	MRSA7	N/A
SCCmec-fus III	ST5	MRSA10	N/A
SCCmec-fus IV	ST45	MRSA8, 9, 11, 12, 16, 19, 20, 21, 23	N/A

SCC, staphylococcal cassette chromosome; N/A, not applicable.