Neomycin (NEM)

Neomycin is an aminoglycoside antibiotic found in many topical medications such as creams, ointments, and eyedrops. Neomycin belongs to aminoglycoside class of antibiotics that contain two or more aminosugars connected by glycosidic bonds. Due to the inherent oto- and nephrotoxicity of these substances, systemic use has declined, as safer alternatives have become available. Neomycin resistance is conferred by either one of two aminoglycoside phosphotransferase genes. A neo gene is commonly included in DNA plasmids used by molecular biologists to establish stable mammalian cell lines expressing cloned proteins in culture; many commercially available protein expression plasmids contain neo as a selectable marker. Non-transfected cells will eventually die off when the culture is treated with neomycin or similar antibiotic.