Table 3. Minimum inhibitory concentrations (MICs) of PcephPT, PT, cephalothin, and ceftriaxone against E. coli MG1655 copA knockout, LEM8, expressing different β-lactamases.
Bacteria were incubated in LB medium at 37 °C while shaking at 200 rpm for 20 h. Growth was evaluated by OD600. Concentrations tested: 140 μM, 70 μM, 35 μM, 17.5 μM, 8.8 μM, 4.4 μM, 2.2 μM, 1.1 μM. For PcephPT, 2.2 μM = 1 μg/mL (see Table S2 for MIC values in μg/mL). MICs within one dilution factor were not considered significantly different. At least two biological replicates were performed with a minimum of at least four total technical replicates.
| Strain | β-lactamase | PcephPT(μM) | Pyrithione (μM) | Cephalothin (μm) | Ceftriaxone (μm) | ||||
|---|---|---|---|---|---|---|---|---|---|
| compound only | + 10 μM CuCl2 | + 2 mM BCS | compound only | + 10 μM CuCl2 | + 2 mM BCS | compound only | compound only | ||
| MG1655 LEM8 copAΔ | null | 35 | 35 | 70 | 17.5 | 4.4 | >140 | 70 | <1 |
| TEM-1 | 35 | 8.8 | >140 | 17.5 | 4.4 | >140 | >140 | <1 | |
| CTX-M-1 | 8.8 | 2.2 | >140 | 17.5 | 4.4 | >140 | >140 | >140 | |
| CMY-2 | 17.5 | 4.4 | >140 | 17.5 | 4.4 | >140 | >140 | >140 | |
| NDM-1 | 17.5 | 4.4 | >140 | 17.5 | 4.4 | >140 | >140 | 70 | |