TABLE 1.
Antibiotic susceptibilities of representative S. typhimurium isolates and E. coli transconjugant clones
| Strain | MIC of β-lactam(s) (μg/ml)
|
Resistance to other antibioticsb | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Ampicillin | Piperacillin | Amoxicillin-clavulanate (2:1) | Ticarcillin-clavulanatea | Piperacillin-tazobactama | Cefotaxime | Ceftriaxone | Ceftazidime | Aztreonam | Cefepime | ||
| S. typhimurium R-893 | >256 | >256 | 32 | 32 | 4 | >128 | >128 | 8 | 64 | 32 | Su, Tm, Te, C, Gm, Tb |
| E. coli (type 1) | >256 | >256 | 32 | 16 | 2 | >128 | >128 | 2 | 32 | 16 | Su, Tm, Te, C, Gm, Tb |
| E. coli (type 2) | >256 | >256 | 16 | 16 | 2 | >128 | >128 | 2 | 64 | 16 | None |
| S. typhimurium H-140 | >256 | >256 | 32 | 64 | 8 | >128 | >128 | 16 | 128 | 64 | Su, Tm, Te, C, Gm, Tb |
| E. coli (type 1) | >256 | >256 | 32 | 64 | 4 | >128 | >128 | 4 | 64 | 32 | Su, Tm, Te, C, Gm, Tb |
| E. coli (type 2) | >256 | >256 | 32 | 64 | 4 | >128 | >128 | 4 | 64 | 32 | None |
| E. coli 26R793 | 2 | 1 | 2 | 2 | 1 | 0.12 | 0.12 | 0.24 | 0.06 | 0.06 | |
a
Inhibitor fixed at 4 μg/ml.
b
Su, sulfonamide; Tm, trimethoprim; Te, tetracycline; C, chloramphenicol; Gm, gentamicin; Tb, tobramycin.