TABLE 1.
MICs of β-lactams for isolates S. marcescens MRSN 696556, C. koseri MRSN 755319, and recombinant strains E. coli TOP10 with or without KPC-82 or KPC-2
| β-lactam(s)a | MIC (μg/ml) of: |
||||
|---|---|---|---|---|---|
| S. marcescensb MRSN 696556 (KPC-2) | C. koserib MRSN 755319 (KPC-82) | E. colic TOP10 (KPC-82) | E. colic TOP10 (KPC-2) | E. colic TOP10 (pBCSK) | |
| Ampicillin | >16 | >16 | >16 | >16 | ≤8 |
| Ampicillin-sublactam | >16 | >16 | >16 | >16 | ≤4 |
| Piperacillin-tazobactam | >64 | >128 | 32 | >128 | ≤8 |
| Ceftriaxone | >64 | >32 | 32 | >32 | ≤0.5 |
| Cefepime | >16 | >32 | 16 | 32 | ≤4 |
| Ceftazidime | 16 | >16 | >16 | >16 | 4 |
| Ceftazidime-avibactam | 8 | 128 | 64 | 0.5 | 0.25 |
| Ceftolozane-tazobactam | NDd | >16 | >16 | >16 | ≤1 |
| Aztreonam | ND | >16 | >16 | >16 | ≤1 |
| Ertapenem | >8 | 4 | 0.5 | 4 | ≤0.25 |
| Imipenem | >4 | 4 | 1 | >8 | ≤0.5 |
| Meropenem | >4 | 2 | ≤0.5 | >8 | ≤0.5 |
| Meropenem-vaborbactam | 0.125 | 0.125 | ND | ND | ND |
a
Tazobactam and avibactam were added at a fixed concentration of 4 μg/ml.
b
Performed in duplicate using a Vitek 2 in the MRSN College of American Pathologists (CAP)-accredited laboratory.
c
Performed in two biological duplicates (distinct transformants confirmed by Sanger sequencing) using a Gram-negative GN4F AST plate (Thermo Fisher).
d
ND, not determined.