Antibiotic GP, a new aminoglycoside antibiotic complex produced by Micromonospora echinospora mutant 129-P1, which can tolerate higher concentrations of phosphate

Antibiotic GP, a new aminoglycoside antibiotic complex produced by Micromonospora echinospora mutant 129-p1, which can tolerate higher concentrations of phosphate was studied. This complex can be separated into two components, antibiotic GPA and antibiotic GPB. The results of the physico-chemical and biological properties showed that antibiotic GPB was identical to antibiotic JI-20B produced by Micromonora purpurea JI-20, and antibiotic GPA was identical to antibiotic TPJ-B which produced by means of microbial transformation of antibiotic JI-20B resulted from Micromonospora sagamiensis NRRL-10060/31. The antibacterial activities of antibiotic GPA and GPB appear to be similar to that of Gentamicin except for against Pseudomonas aeruginosa. The toxicity tests in mice showed that the toxicity of antibiotic GPA and GPB were lower than that of Gentamicin and the protection tests in vivo in mice indicated that the activities of antibiotic GPA and GPB in vivo were more potent than that of Gentamicin. The synergism between antibiotic GPA and GPB against bacteria can be seen in vitro and in vivo.