Variant SCC<i>mec</i> elements.

<p><b>a)</b> SCC<i>mec</i> for archetypal type II, MRSA252 (NC_002952), compared to isolates CMFT2 and CMFT492. The cassette of CMFT2 shows the typical features of a type II SCC<i>mec</i>; a class A <i>mec</i> complex and a class 2 <i>ccr</i> complex. However, there is an additional SCC carrying type I <i>ccr</i> genes situated at the 5′ end of the element. CMFT492 is superficially similar and contains the same additional class 1 <i>ccr</i> complex. However, it lacks two of the major features of most type II SCC<i>mec</i> elements; the plasmid vector pUB110 and transposon Tn<i>554</i>. <b>b)</b> SCC<i>mec</i> type IVk: SCC<i>mec</i> for CMFT201 compared to CA05 (AB063172, type IV(2B)) and 45394F (GU122149). The cassette of CMFT201 shows the typical features of a type IV SCC<i>mec</i> (CA05); a class B <i>mec</i> complex and a class 2 <i>ccr</i> complex. However, there are additional SCC elements with an SCC carrying type I <i>ccr</i> genes situated at the 5′ end of the cassette. This is a similar structure to that shown by strain 45394F (unpublished). <b>c)</b> Type IVh variant SCC-SCC<i>mec</i> element for CMFT3119 compared to strains ZH47 (AM292304) and M1 (HM030720). The cassette of CMFT3119 shows the typical features of a type IV SCC<i>mec</i>; a class B <i>mec</i> complex and a class 2 <i>ccr</i> complex. However CMFT3119 contains an additional SCC carrying a <i>ccrC</i> gene upstream of the <i>mec</i> complex, similar to the recombination seen in ZH47. In contrast to ZH47 there is not a Tn<i>4001</i> but instead part of the arginine catabolic mobile element (ACME), seen in <i>S. epidermidis, S. haemolyticus</i> and USA300, has been inserted. This <i>arc</i> gene cluster is very similar to that seen in the recently identified strain M1.