Table 2. Comparison of amino acid substitutions at genes associated with vancomycin intermediate resistance among Staphylococcus aureus 13420 and hVISA, VISA and VSSA isolates previously sequenced.
| Genes | 13420a | hVISA/VISA (n = 101) | VSSA (n=32) | References |
|---|---|---|---|---|
| vraS | S239L | I5Nb,c, G88D, L123H, S167N, S239Ld, F243S, K272I, L315M, I317T, F321L | nd | [6, 50, 51, 53] |
| vraS | nd | E59D, A113V, S164P | S26R, E59D, F85L, I86L, E87K, A113V, R117H, R121S, S164P | [50, 51] |
| graS | nd | R14L, L26F, M29R, I59L, D148Q, A153P, T224I, N289Y, V301E, V304E, N332K | L26F, I59L, D148Q, T224I, S303R, R325K, N332K, V676I | [50, 51] |
| graR | nd | D148Q, F151L, N197Sb | M90N, D147E, D148Q, S197G, V135I, V136I | [50, 51] |
| tcaA | F31L, L218P, Y237H, S448P | M202T, L218P, Y237H, T262S, T279I, R283H, G312D, N371I | K2E, N133I, M202T, L218P, Y237H, Y262S, R283H, G312D, I431V | [50, 51] |
| tcaB | L173M, V360I | A91P, I232L, W308G | H6Y, V145F, F207L, S341N, V360I, K396R | [50, 51] |
a MIC of 4 mg/L for vancomycin; hVISA – S. aureus with heterogeneous intermediate resistance to vancomycin; VISA – S. aureus with intermediate resistance to vancomycin; VSSA – Vancomycin susceptible S. aureus; bMu50 - VISA clinical strain with vraS (I5N), msrR (E146K),graR (N197S),rpoB (H481Y), and fdh2 (A297V) mutations and MIC of 12 mg/L for vancomycin; c Mu3- hVISA clinical strain with vraS (I5N) and msrR (E146K) mutation and MIC of 3 mg/L for vancomycin; d H14 - hVISA strain with vraS (S329L) mutation and MIC of 2 mg/L for vancomycin; A Alanine; D Aspartic acid; E Glutamic acid; F Phenylalanine; G Glycine; H Histidine; I Isoleucine; K Lysine; L Leucine; M Methionine; N Asparagine; P Proline; Q Glutamine; R Arginine; S Serine; T Threonine; V Valine; Y Tyrosine; nd - not detected; n - number of isolates; In bold: mutations found among 13420 and hVISA/VISA and VSSA isolates.