Table 6.
The Antibiotic Susceptibilities of BL21 (DE3) E. coli Expressing CME, BlaB, GOB, Putative Efflux Proteins or the pET28a(+) Vector
| BL21 with Recombinant Plasmid | MIC (μg/mL) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AMP | PIP | CFZ | CXM | CAZ | CRO | FEP | AZT | IPM | AK | CIP | TGC | |
| pET28a(+) vector | 0.5 | 0.5 | 1 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.125 | 8 | <0.125 | 4 |
| pET-CME | 32 | 4 | 32 | 32 | 64 | 1 | <0.125 | 8 | 0.25 | 8 | <0.125 | 4 |
| pET-BlaB | 256 | 128 | 2 | 16 | 4 | <0.125 | <0.125 | <0.125 | 4 | 4 | <0.125 | 4 |
| pET-GOB | 4 | 2 | 4 | 8 | 16 | <0.125 | <0.125 | <0.125 | 2 | 4 | <0.125 | 4 |
| pET-ABC | 0.5 | 1 | 1 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.25 | 8 | <0.125 | 4 |
| pET-MFS | 1 | 0.5 | 2 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.25 | 8 | <0.125 | 4 |
| pET-MATE | 0.5 | 0.5 | 2 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.25 | 8 | <0.125 | 4 |
| pET-SMR | 1 | 0.5 | 2 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.25 | 8 | <0.125 | 4 |
| pET-RND | 0.5 | 0.5 | 2 | 1 | 1 | <0.125 | <0.125 | <0.125 | 0.25 | 8 | <0.125 | 4 |
Note: Bold face indicate MIC values that increase at least 4-fold as compared to the pET28a(+) vector.
Abbreviations: MIC, minimum inhibitory concentration; AMP, ampicillin; PIP, piperacillin; CFZ, cefazolin; CXM, cefuroxime; CAZ, ceftazidime; CRO, ceftriaxone; FEP, cefepime; AZT, aztreonam; IPM, imipenem; AK, amikacin; CIP, ciprofloxacin; TGC, tigecycline; CME, extended-spectrum serine-beta-lactamase CME (class A); BlaB, metallo-beta-lactamase BlaB (subclass B1); GOB, metallo-beta-lactamase GOB (subclass B3); ABC, efflux ABC transporter (ATP-binding protein); MFS, MFS-type transporter; MATE, MATE family of MDR efflux pump; SMR, small multidrug resistance family (SMR) protein; RND, CzcABC family efflux RND transporter.