Antibacterial peptides and the outer membranes of gram-negative bacilli.

Major problems are being experienced in human medicine from antibiotic resistant bacteria [ 11. Furthermore, no new chemical class of antibiotics has been introduced into medicine in the past two decades [2]. Although many antibiotic structures have been subjected to intensive chemical manipulation to yield novel derivatives with extended activity spectra, resistance to such antibiotics has usually emerged quickly. An ideal antimicrobial agent, in the antibiotic resistance era, would be one that does not suffer intrinsic or induced resistance problems, or one that directly attacks a common resistance mechanism. Antibacterial peptides that represent a conserved theme in host antimicrobial defences throughout nature are of great interest in this regard and potentially provide the first novel class of antimicrobial agents since the introduction of nalidixic acid in 1970.