Fig. 2

Distribution of antibiotic resistance determinants in the archetypal MRSA clone. A maximum likelihood tree of historic MRSA isolates (n = 209) plus the COL reference is displayed on the left, and the panels on the right indicate dates of isolation (coloured according to year; see key below for years), and the presence (purple boxes) and absence (white space) of genetic determinants responsible for antibiotic resistance in the genomes of the isolates. The identity of genetic determinants are listed at the top and divided into acquired genes (red text; left hand side), and core mutations (green text; right hand side). The antibiotics linked to the genetic determinants for the acquired genes are: β-lactams, blaZ and mecA; chloramphenicol, catA1, catA2, and catA3; erythromycin, ermA; clindamycin, linA; aminoglycosides, aacA-aphD, aad9, aadD, aph3A, and str; tetracycline, tetM and tetK; disinfectants, qacA and qacC. And for the core gene mutations are: streptomycin substitution of arginine for a lysine at residue 56 (K56R) of the ribosomal protein rpsL; fusidic acid, substitution of a proline for a leucine at residue 406 (P404L) of the transcription elongation factor fusA; trimethoprim, substitution of an tyrosine for a phenylalanine at residue 99 (F99Y) of the dihydrofolate reductase dfrA. Sixteen isolates lacked complete type I SCCmec elements, 4 of which contained internal deletions in the SCCmec element but retained the mecA gene