TABLE 3.

FusA (EF-G) alternation sites detected in 41 S. aureus isolates

Amino acid substitution (domaina)Nucleotide substitutionNo. of isolatesFusidic acid MIC (μg/ml)
P404LbCCA→CTA2 (1 MRSA, 1 MSSA)8, 16
P406LbCCA→CTA116
E444Kf GAA→AAA116
G451VbGGT→GTT28, 16
M453IdATG→ATA28
H457QgCAC→CAA18
H457Yb CAC→TAC5128, >128
L461Kb TTA→AAA6>128
L461SbTTA→TCA24, 8
P478Sf CCA→TCA1 (MSSA)8
M651I (domain V)fATG→ATA1 (MSSA)2
M16I (domain I)c, H457YbATG→ATA, CAC→TAC316, 32, 64
A67T (domain I)e, H457Yb GCA→ACA, CAC→TAC3128, >128
A70V (domain I)c, H457YbGCA→GTA, CAC→TAC1>128
A71V (domain I)c, P404LbGCT→GTT, CCA→CTA18
R76C (domain I)f, H457Yb CGT→TGT, CAC→TAC1>128
A376V (domain II)c, L456FbGCT→GTT, CTT→TTT132
E444Vf, L461FbGAA→GTA, TTA→TTT132
H457Qg, L461FbCAC→CAA, TTA→TTT4128
H457Qg, L461KbCAC→CAG, TTA→AAA1>128
L461Kb, C473Sf TTA→AAA, TGT→AGT1>128
  • a No domain specification indicates domain III of EF-G.

  • b Previously reported for S. aureus (4, 24).

  • c The amino acid substitutions have been identified as compensatory mutations in S. aureus (24).

  • d Reported for Salmonella typhimurium (15).

  • e The amino acid substitution has been reported to have no impact on fusidic acid resistance or compensation for fitness in S. aureus (3).

  • f The amino acid substitutions were first identified among S. aureus isolates.

  • g The amino acid substitution H457Q was recently reported by Castanheira et al. (5).