Table 3. Synergy between B1 and PB against Gram-negative bacteria.
| Strains a | MICs of B1 alone | MICs of PB alone | MICs of 4 μg ml–1B1 combined with PB | FICI b |
| Aba-ATCC19606 | >64 | 1 | 0.5 | 0.53 |
| Aba-1 | >64 | 4 | 2 | 0.53 |
| Aba-2 | >64 | 4 | 1 | 0.28 |
| Aba-3 | >64 | 1 | 0.5 | 0.53 |
| Aba-4 | >64 | 1 | 0.5 | 0.53 |
| KPN-2677 | >64 | 16 | 0.5 | 0.06 |
| KPN-2967 | >64 | 4 | 0.5 | 0.16 |
| Eco-ATCC25922 | >64 | 0.5 | 0.25 | 0.53 |
| Eco-2944 | >64 | 0.5 | 0.125 | 0.28 |
| Eco-2945 | >64 | 0.5 | 0.125 | 0.28 |
| Pae-ATCC27853 | >64 | 1 | 1 | 1.03 |
| Pae-1399 | >64 | 2 | 1 | 0.53 |
| Pae-1292 | >64 | 2 | 2 | 1.03 |
aAba, Acinetobacter baumannii; KPN, Klebsiella pneumoniae; Eco, E. coli; Pae Pseudomonas aeruginosa.
bFICI [less-than-or-eq] 0.5 = synergy, 0.5–0.75 = partial synergy, 0.76–1 = an additive effect.