Table 1.
Antibiotic susceptibility profile by broth microdilution of C. freundii ISCF142, E. coli DH10β-harboring recombinant β-lactamase blaOXA-900, and E. coli DH10β without the β-lactamase gene insert (negative control).
| MIC in µg/mL (CLSI Breakpoints) | ||||
|---|---|---|---|---|
| Antibiotic Class | Antibiotic | C. freundii Isolate ISCF142 | Transformant DH10β (OXA-900) |
DH10β (Negative Control) |
| Carbapenems | Meropenem | 1 (S) | 1 (S) | <0.12 (S) |
| Imipenem | 1 (S) | 2 (S) | <0.5 (S) | |
| Ertapenem | 1 (I) | 1 (I) | <0.12 (S) | |
| Cephalosporins | Cefotaxime | 8 (R) | <0.5 (S) | <0.5 (S) |
| Ceftazidime | >16 (R) | <0.5 (S) | <0.5 (S) | |
| Cephalosporin combinations | Ceftazidime/ avibactam a |
<0.5 (S) | <0.5 (S) | <0.5 (S) |
| Ceftolozane/ tazobactam a |
>32 (R) | 8 (S) | <0.5 (S) | |
| Monobactams | Aztreonam | >32 (R) | <0.5 (S) | <0.5 (S) |
| Penicillin combinations | Piperacillin/ tazobactam a |
>32 (R) | >32 (R) | 2 (S) |
| Amoxicillin/clavulanic acid b | >64 (R) | >64 (R) | <4 (S) | |
| Fluoroquinolones | Ciprofloxacin | 0.25 (S) | 0.12 (S) | 0.12 (S) |
| Polymixins | Colistin | 1 | 0.25 | 0.5 |
| Aminoglycosides | Tobramycin | 1 (S) | <1 (S) | <1 (S) |
| Tetracyclines | Tigecycline | 0.25 (S) | <0.25 (S) | <0.25 (S) |
| Sulfonamide combinations | Trimethoprim/ sulfamethoxazole c |
1 (S) | <1 (S) | <1 (S) |
a Tazobactam and avibactam at a fixed concentration of 4 µg/mL. b Clavulanic acid at a fixed concentration of 2 µg/mL. c Sulfamethoxazole at a fixed concentration of 19 µg/mL.