Antibacterial activity of the recombinant antimicrobial peptide Ib-AMP4 from Impatiens balsamina and its synergy with other antimicrobial agents against drug resistant bacteria.

Ib-AMP4 is an antimicrobial peptide of Impatiens balsamina (Balsaminaceae). Ib-AMP4 was produced as a recombinant peptide and in this study its antimicrobial activity against human bacterial pathogens was investigated. Ib-AMP4 was bactericidal against both Gram positive and Gram negative bacteria with MIC values between 0.49 and 3.5 microM in sensitive species. A genuine synergistic effect was achieved when IB-AMP4 was employed in combination with the plant monoterpene thymol against drug-resistant Klebsiella pneumoniae (KPC) ATCC700603, or with the antibiotics vancomycin or oxacillin against Enterococcus faecalis (VRE) ATCC51299.