TABLE 4.
MICs of passaged strains and their isogenic pbp4 deletion knockout strains
| Strain | MIC (μg ml−1)a |
||||||
|---|---|---|---|---|---|---|---|
| NAF | AMP | CTX | FOX | CFZ | BPR | CPT | |
| SRB | 8 | 4 | 32 | 1 | 16 | >64 | 4 |
| SRB Δpbp4 | 0.25 | 0.25 | 0.25 | 0.5 | 0.25 | 4 | 0.125 |
| SRT | 64 | >256 | >256 | 8 | >256 | 8 | >64 |
| SRT Δpbp4 | 0.25 | 0.25 | 2 | 4 | 0.25 | 0.5 | 0.125 |
| SgapT | >256 | >256 | 256 | 8 | 256 | >64 | 64 |
| SgapT Δpbp4 | 0.25 | 0.25 | 1 | 2 | 0.25 | 0.25 | 0.125 |
| SpT | >256 | >256 | >256 | 8 | >256 | >64 | >64 |
| SpT Δpbp4 | 0.25 | 0.25 | 2 | 4 | 0.25 | 0.5 | 0.125 |
a
NAF, nafcillin; AMP, ampicillin; CTX, ceftriaxone; FOX, cefoxitin; CFZ, cefazolin; BPR, ceftobiprole; and CPT, ceftaroline. The CLSI breakpoint for resistance is ≥4 μg ml−1 (45).