Table 2.
Minimum inhibitory concentrations (MICs) (µM) and therapeutic index (TI) of the designed peptides.
| Bacterial Species | IRGG | IRpG | FRGG | FRpG | LRGG | LRpG | LRα | Melittin | |
|---|---|---|---|---|---|---|---|---|---|
| MIC (µM) | |||||||||
| Gram (−) | |||||||||
| Escherichia coli ATCC25922 | 8 | 4 | 8 | 8 | 2 | 2 | 2 | 1 | |
| E. coli K88 | 16 | 16 | 16 | 8 | 4 | 2 | 4 | 2 | |
| Salmonella Pullorum NCTC5776 | 32 | 16 | 16 | 16 | 4 | 4 | 2 | 2 | |
| Klebsiella pneumonia CMCC46117 | 32 | 32 | 16 | 16 | 8 | 4 | 4 | 4 | |
| Pseudomonas aeruginosa ATCC27853 | 32 | 32 | 32 | 32 | 8 | 8 | 4 | 2 | |
| Gram (+) | |||||||||
| Staphylococcus aureus ATCC25923 | >128 | >128 | 32 | 16 | 16 | 16 | 4 | 2 | |
| S. aureus ATCC29213 | >128 | >128 | 16 | 16 | 16 | 16 | 8 | 1 | |
| S. aureus ATCC43300 | >128 | >128 | 32 | 32 | 32 | 16 | 8 | 2 | |
| Enterococcus faecalis ATCC29212 | >128 | >128 | 32 | 32 | 32 | 32 | 16 | 1 | |
| GM 1 (µM) | |||||||||
| Gram (−) | 21.1 | 16 | 16 | 13.9 | 4.6 | 3.5 | 3 | 2 | |
| Gram (+) | 256 | 256 | 26.9 | 22.6 | 22.6 | 19.0 | 8 | 1.4 | |
| MHC10 2 (µM) | 512 | 512 | 128 | 128 | 256 | 256 | 4 | 0.25 | |
| TI 3 | |||||||||
| TI (−) | 24.2 | 32 | 8 | 9.2 | 55.6 | 73.1 | 1.3 | 0.125 | |
| TI (+) | 2 | 2 | 4.8 | 5.7 | 11.2 | 13.5 | 0.5 | 0.178 | |
1 Geometric mean (GM) of MICs for the nine strains was measured. A value of 256 μM was used for the TI when no antimicrobial activity was examined at 128 μM. 2 Minimum hemolysis concentration 10% (MHC10) was characterized as the lowest concentration inducing 10% hemolysis. 3 TI was calculated as MHC10/GM.