Geneticin (G-418) is produced by Micromonospora phodorangea. The antibiotic has brad spectrum antibacterial activity similar to gentamicins and other previously described aminoglycosides but of particular interest because of its high activity against protozoa, amoebae, tapeworm and pinworm infections in mice. G418 blocks polypeptide synthesis by inhibiting the elongation step in both prokaryotic and eukaryotic cells. G418 is commonly used in laboratory research to select genetically engineered cells.