A screening method to identify antibiotics of the aminoglycoside family

A simple and selective screening method was developed for detecting new aminoglycoside (AMG) antibiotics from actinomycetes strains propagated on solid culture media. The first phase of the screening program is designed to isolate AMG-type activities using: 1) two Serratia marcescens strains, one susceptible and one resistant to AMGs, 2) the high tolerance of AMGs to heat in acidic solutions and 3) the specific resistance of a streptothricin producing strain of Streptomyces lavendulae to streptothricin antibiotics. The second phase of the screening program identifies already known AMG antibiotics through the characteristic spectrum of action which each AMG shows toward a group of bacterial strains synthesizing various AMG-inactivating enzymes.