Ferrocins, new iron-containing peptide antibiotics produced by bacteria. Taxonomy, fermentation and biological activity.

A Gram-negative bacterium was found to produce new iron-containing peptide antibiotics, ferrocins A, B, C and D, and the producing bacterium was characterized and identified as Pseudomonas fluorescens YK-310. These new antibiotics showed antibacterial activity against Gram-negative bacteria in vitro. Although the ferrocins showed similar antibacterial activity against both Escherichia coli and Pseudomonas aeruginosa on the standard assay media, they showed strong therapeutic effects selectively against P. aeruginosa in experimentally infected mice.