Piscidins: a novel family of peptide antibiotics from fish.

The global emergence of many new infectious diseases, as well as concerns about the antibiotic resistance of an increasing number of microbial pathogens, necessitates that new approaches be sought in combating these serious infections. Peptide antibiotics, host-produced antimicrobial defenses that have been isolated from all types of organisms, from plants to mammals, possess a number of characteristics that make them attractive drug candidates. An example of the diversity and potential for new discoveries in this area is a novel family of peptide antibiotics named "piscidins," which have been recently isolated from fish. Piscidins have potent, broad-spectrum in vitro activity against many pathogens, including multidrug-resistant bacteria. Interestingly, piscidins reside in mast cells, a highly common tissue granulocyte of uncertain function that is ubiquitous in all vertebrate classes. The discovery of peptide antibiotics in mast cells may be a previously unappreciated, yet crucial, function for this highly common yet enigmatic immune cell. (c) 2003 Prous Science. All rights reserved.