ARC and infection: The high numbers of SCCmec-associated elements in the primary GWAS (Supplementary Data 3) and among the 61 genes containing phenotypically correlated hits (including ccrB, mecR1, mecA, maoC, arc, arcB-2 and other genes encoding hypothetical proteins, Supplementary Data 1) indicates the importance of relative abundance of SCCmec in infection strains, compared with those from the commensal environment.