ERYTHROMYCIN

antibiotic synthesized by a soil organism, Streptomyces erythraeus. Erythromycin, which interferes with the synthesis of certain vital proteins in some microorganisms, may be either bacteriostatic (i.e., it inhibits bacterial reproduction but does not kill bacterial cells) or bactericidal (i.e., it kills bacteria by direct action), depending on its concentration and the type of microorganism against which it is used. Among the disease-causing agents susceptible to erythromycin are Staphylococcus aureus (the pus-producing bacterium) and several species of Streptococcus (bacteria that cause throat infections, pneumonia, sinusitis, and other diseases).