[Antibiotic properties of Pseudomonas cepacia]

The antibiotic activity and some of the physicochemical properties of the pigment produced by P. cepacia 4137 were studied. The pigment was isolated from the medium with chloroform. Preparative chromatography on columns with silica gel and thin-layer chromatography on Silufol plates revealed red-orange and straw-yellow fractions in the composition of the antibiotic. The latter fraction showed a significant antimicrobial activity against gram-positive and gram-negative bacteria, fungi and yeasts. The red fraction was inferior to the yellow one with respect to its antimicrobial activity. Both substances could be stained with a butanol solution of FeCl3. The absorption maxima of their methanol solutions were observed at 225, 325 and 455 nm with respect to the red fraction and at 220, 330 and 405 with respect to the yellow fraction. The elemental analysis of a more highly purified red fraction showed the following: C 54.10, H 6.85, N 7.93 and O 31.12. It is suggested that the substances are derivatives of hydroxyphenazine carboxylic acids.