This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Buckmire, F. L. A. Articles by Winkelhake, J. L. Search for Related Content PubMed PubMed Citation Articles by Buckmire, F. L. A. Articles by Winkelhake, J. L.

 Previous Article  |  Next Article 

Antimicrob Agents Chemother. 1977 June; 11(6): 1010-1016
Copyright © 1977 American Society for Microbiology. All Rights Reserved.

Bactericidal Activity of Macromomycin, an Antitumor Antibiotic

Department of Microbiology, The Medical College of Wisconsin, Milwaukee, Wisconsin 53233

ABSTRACT

Susceptibility testing by the broth dilution method showed that all the gram-positive but only some of the gram-negative bacteria tested were susceptible to the antitumor antibiotic, macromomycin (MCR; NSC 170105). The minimal inhibitory concentration for the susceptible organisms was less than 3 µg/ml. The action of MCR was bactericidal; however, at very high concentrations (50 µg/ml and above) some organisms occasionally escaped death. None of the escaped organisms was resistant to MCR. In combination with other commonly used antibiotics, MCR displayed partial synergy for Pseudomonas aeruginosa (from a minimal inhibitory concentration of >100 to 12.5 µg/ml with 100 µg of chloramphenicol per ml) and for Bacillus pumilus and Staphylococcus aureus (from 1.6 to 0.4 µg/ml and below) with polymyxin B. As with mammalian cells, ¹²⁵I-labeled MCR was irreversibly bound to both gram-positive and -negative bacteria. Treatment with trypsin of the ¹²⁵I-labeled MCR-exposed cells did not release the bound MCR or reverse its lethal effect. When in solution in a protective buffer at 4°C, MCR was stable for up to 45 days; at 37°C, however, 25% of its bactericidal activity was lost in 72 h. Loss of activity was enhanced 16-fold in the presence of both heated and unheated pooled human sera. Urine had no effect on the activity of MCR.