Table 2 Checkerboard assays between penicillin and the cpl-1 endolysin with the penicillin-resistant pneumococcal isolates. The table indicates minimal inhibitory concentrations observed for penicillin, endolysin cpl-1 or the different combinations thereof. FIC is the fractional inhibitory concentration, which indicates synergy if values are ≤ 0.50. The EUCAST breakpoint for penicillin resistance is set at 2.00 µg/mL
AMR 12,116 | AMR 19,000 | AMR 68,715 | |
|---|---|---|---|
Cpl-1 | 5.00 µM | 2.50 µM | 2.50 µM |
Penicillin | 4.00 µg/mL | 4.00 µg/mL | 16.00 µg/mL |
Penicillin + cpl-1 | 0.50 µg/mL | 1.00 µg/mL | 1.00 µg/mL |
Cpl-1 + penicillin | 0.62 µM | 0.62 µM | 0.62 µM |
FIC | 0.25 | 0.50 | 0.31 |