Figure 1

Synergistic antibacterial effect of AMPs combined with antibiotics in vitro. The synergistic antimicrobial activity of combinations of AMPs (PMAP-36 and PR-39) and antibiotics (tetracycline and gentamicin) against multidrug-resistant ExPEC PCN033 (A) and RS218 (B) is shown. The synergistic antibacterial activity was determined by the fractional bactericidal concentration index (FBCI). In each contour map, different coloured lines, including green, grey, and purple, represent synergy, additivity, and independence, respectively.