E-Mycin n 1: an antibiotic (trade name Erythrocin or E-Mycin or Ethril or Ilosone or Pediamycin) obtained from the actinomycete Streptomyces erythreus; effective against many Gram- positive bacteria and some Gram-negative [syn: {erythromycin}, {Erythrocin}, {E-Mycin}, {Ethril}, {Ilosone}, {Pediamycin}]