title: Macrolide resistance in Staphylococcus aureus: induction of macrolide-resistant protein synthesis.
abstract: Induction of resistance to macrolide-, lincosamide-, and streptogramin B-type antibiotics in Staphylococcus aureus was studied by monitoring the appearance of erythromycin A (EM)-resistant [(14)C]leucine incorporation. Examination of the induction process revealed saturation kinetics and a time course much like that reported for penicillinase in gram-positive bacteria. Induction kinetics in exponentially growing cells were sigmoidal and appeared to reach a maximum and constant rate when growth reached stationary phase. Since the induction of EM-resistant colony-forming ability was complete within 60 min, ribosome modification cannot be limited to a fraction of the population and must occur in essentially every cell. However, EM-resistant growth was expressed in cells where less than half the [(14)C]leucine-incorporating activity was resistant to EM. This suggests that resistance requires that only a threshold level of ribosome modification be exceeded and that, once exceeded, resistance is dominant to sensitivity.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D004352:Drug Resistance, Microbial; D014176:Protein Biosynthesis / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins