Determination of binding parameters of macrolides, lincosamides, and streptogramins to Legionella pneumophila.
Parameters of [3H]erythromycin binding to Legionella pneumophila were determined in vitro using both an equilibrium and a kinetic method. Different L. pneumophila serogroups, 1-3, and a virulent strain serogroup, 1, were tested. All strains of bacteria exhibited the same binding pattern, with a dissociation constant of 0.15 microM. Other macrolides, streptogramin B-types, and lincosamides competitively displaced bound erythromycin suggesting that these compounds share common binding sites on the bacteria. Minimum inhibitory concentration (MIC) values for macrolides, streptogramin B-types, and lincosamides were determined with buffered charcoal yeast extract (BCYE) medium. A good correlation (r = 0.994) was found between the corresponding inhibition constants of these antibiotics and their MIC. It was also noted that for lincosamides the microbiological inactivity was associated with a very low bacterium affinity. Thus, it is concluded that binding parameters of these antibiotics reflect their efficacy against L. pneumophila in vitro and may serve as a useful adjunct in developing new compounds.
D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D004917:Erythromycin / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D007875:Legionella / Q000187:drug effects / Q000378:metabolism*; D008826:Microbial Sensitivity Tests
D000900:Anti-Bacterial Agents; D004917:Erythromycin