TABLE 1.
Antimicrobial susceptibility profiles of clinical E. coli isolates and E. coli TG1 strains carrying various blaCTX-M genes
| Strain identification | β-Lactamase | MICs (μg/ml) fora: |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PIP | CAZ | CTX | FEP | CMZ | PIP-TAZ | CFP-SUL | CTX-SUL | CTX-CLA | CAZ-CLA | CTX-AVI | FOS | PE | ||
| EC600 | ≤8 | 0.5 | ≤0.25 | ≤0.5 | 1 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 | |
| ZE36 | CTX-M-199 | >256 | >32 | 1,024 | >32 | >32 | 128/4 | 128/64 | 128/64 | 16/8 | 64/32 | 2/1 | >512 | 2 |
| ZE36-T | CTX-M-199 | 256 | 16 | 1,024 | 32 | 1 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | 1 |
| ZE722 | CTX-M-199 | >256 | 8 | 1,024 | >32 | 2 | 32/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | >512 | 4 |
| ZE722-T | CTX-M-199 | 128 | 16 | 1,024 | 16 | 2 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | 1 |
| EB70 | CTX-M-199 | >256 | 8 | 1,024 | >32 | ≤0.5 | 64/4 | 32/16 | 32/16 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | 8 | 2 |
| EB70-T | CTX-M-199 | 256 | 16 | 1,024 | 32 | 1 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | 2 |
| JH89 | CTX-M-64 | >256 | 32 | 1,024 | >32 | 1 | ≤1/4 | 16/8 | 16/8 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | 2 |
| JH89-T | CTX-M-64 | >256 | >32 | 1,024 | 32 | 1 | ≤1/4 | 16/8 | 16/8 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | 1 |
| VCb | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 | |
| CTX-M-199c | CTX-M-199 | 256 | 16 | 1,024 | >32 | ≤0.5 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | 0.25/0.125 | ≤4 | ≤0.5 |
| M199(T109A) | M199(T109A) | 128 | 16 | 256 | 32 | ≤0.5 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | 0.25/0.125 | ≤4 | ≤0.5 |
| M199(T130S) | M199(T130S) | >256 | >32 | 1,024 | >32 | ≤0.5 | ≤1/4 | 4/2 | 4/2 | ≤1/0.5 | 2/1 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| CTX-M-64d | CTX-M-64 | 256 | 16 | 1,024 | 4 | ≤0.5 | ≤1/4 | 2/1 | 2/1 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(A109T) | M64(A109T) | 128 | 8 | 512 | 32 | ≤0.5 | ≤1/4 | 4/2 | 4/2 | ≤1/0.5 | 2/1 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(S130T) | M64(S130T) | 128 | 8 | 512 | >32 | ≤0.5 | 64/4 | 64/32 | 64/32 | ≤1/0.5 | ≤1/0.5 | 0.25/0.125 | ≤4 | ≤0.5 |
| M64(S130D) | M64(S130D) | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(S130G) | M64(S130G) | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(S130N) | M64(S130N) | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(S130V) | M64(S130V) | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
| M64(S130C) | M64(S130C) | ≤8 | ≤0.25 | ≤0.25 | ≤0.5 | ≤0.5 | ≤1/4 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤1/0.5 | ≤0.15/0.07 | ≤4 | ≤0.5 |
For PIP-TAZ, the tazobactam was tested at a fixed concentration of 4 μg/ml. The CFP-SUL, CTX-SUL, CTX-CLA, CTX-AVI, and CAZ-CLA combinations were tested at a 2:1 ratio (antibiotic/inhibitor). PIP, piperacillin; CAZ, ceftazidime; CTX, cefotaxime; FEP, cefepime; CMZ, cefmetazole; PIP-TAZ, piperacillin-tazobactam; CFP-SUL, cefoperazone-sulbactam; CTX-SUL, cefotaxime-sulbactam; CAZ-CLA, ceftazidime-clavulanic acid; CTX-CLA, cefotaxime-clavulanic acid; CTX-AVI, cefotaxime-avibactam; FOS, fosfomycin; PE, polymyxin.
E. coli TG1 carrying the cloning vector pHSG396.
E. coli TG1 carrying pHSG396-blaCTX-M-199 with different point mutations.
E. coli TG1 carrying pHSG396-blaCTX-M-64 with different point mutations.