TABLE 4.

β-Lactam susceptibilities of clinical isolates and Rd recombinants carrying the corresponding ftsI genes

ClassaNo. of strainsStrainbGeometric mean MIC (μg/ml [range])
CefotaximeCefaclorCefdinirCefpodoximeCefditorenCefcapeneAmpicillinImipenemMeropenem
Rd0.00810.250.0310.0080.0080.120.120.031
I12R0.071 (0.063-0.12)38 (16-64)1.8 (0.5-4)0.22 (0.12-0.25)0.029 (0.016-0.063)0.11 (0.063-0.25)0.56 (0.5-1)2.5 (0.5-8)0.071 (0.031-0.12)
C0.059 (0.031-0.12)16 (1-128)1.3 (0.5-4)0.2 (0.12-0.5)0.037 (0.016-0.12)0.089 (0.063-0.12)0.69 (0.5-4)2.2 (0.25-8)0.12 (0.063-0.25)
II4R0.42 (0.25-0.5)64 (64)4.8 (4-8)0.84 (0.5-1)0.089 (0.063-0.12)0.71 (0.25-1)1.0 (1)0.18 (0.063-0.25)0.063 (0.063)
C0.35 (0.12-0.5)32 (32)6.7 (4-8)0.84 (0.5-2)0.18 (0.063-0.25)0.84 (0.5-1)2.0 (1-4)3.4 (2-8)0.18 (0.12-0.25)
III11R0.50 (0.5)68 (64-128)4.0 (4)1.1 (1-2)0.12 (0.12)1.0 (1)0.78 (0.5-1)0.12 (0.12-0.25)0.04 (0.031-0.063)
C0.57 (0.5-1)110 (8-256)8.5 (4-32)1.8 (0.25-4)0.21 (0.12-0.25)1.8 (1-4)3.8 (0.5-16)4.8 (1-32)0.23 (0.031-1)
IV5R0.041 (0.031-0.12)18 (16-32)1.3 (0.5-4)0.14 (0.12-0.25)0.018 (0.016-0.031)0.041 (0.031-0.12)0.50 (0.5)0.38 (0.12-0.5)0.031 (0.031)
C0.031 (0.031)4.0 (1-16)0.87 (0.5-1)0.12 (0.12)0.021 (0.016-0.031)0.041 (0.031-0.063)0.38 (0.063-0.5)0.29 (0.063-0.5)0.036 (0.016-0.063)
V3R0.16 (0.12-0.25)40 (32-64)4.0 (4)0.31 (0.25-0.5)0.032 (0.016-0.12)0.31 (0.25-0.5)0.5 (0.5)0.12 (0.12)0.031 (0.031)
C0.12 (0.063-0.5)6.3 (2-64)4.0 (4)0.40 (0.25-1)0.040 (0.016-0.12)0.20 (0.12-0.5)1.3 (1-2)0.20 (0.12-0.5)0.049 (0.031-0.12)
VI1R0.256440.50.0630.50.50.120.031
C0.56440.50.063110.120.031
  • a Amino acid mutations used as the basis of a classification, as follows: I, N526K; II, N526K + S385T; III, N526K + S385T + L389F; IV, R517H;V, R517H + S385T; VI, R517H + S385T + L389F.

  • b R, recombinants with the ftsI genes from clinical isolates; C, clinical isolates.