Table 1.
MICs, zone diameters and amino acid substitutions in PBPs found in PRGBS isolates AC-13238-1 and AC-13238-2
| Isolate | PEN MIC (mg/L)a |
Disc diffusion (mm) |
Amino acid substitutionsc |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| microdilution | Etestb | WalkAway | VITEK 2 | PEN | OXA | CTB | CTX | PBP2X | PBP1A | PBP2B | |
| AC-13238-1 | 0.5 | 0.5 | 0.12 | UD | 27 | 7 | 0 | 16 | I377V, F395L, V405A, H438Y, V510I | A521V, del719–722, N723S, V726A | V80A |
| AC-13238-2 | 1 | 1 | 0.5 | UD | 23 | 0 | 0 | 15 | I377V, V405A, H438Y, V510I, Q557E | T526I, del719–722, N723S, V726A | V80A |
PEN, penicillin; OXA, oxacillin; CTB, ceftibuten; CTX, cefotaxime; UD, undetermined.
a
Each MIC value was obtained consistently across three independent assays.
b
Same PEN MIC determined by Etest according to EUCAST and CLSI guidelines.
c
The amino acid positions are those of the corresponding genes in strain 2603V/R (GenBank accession number NC_004116). Substitutions strongly associated with PRGBS are shown in bold.