Neomycin is an antibiotic that is found in many topical medications such as creams, ointments and eyedrops.
Uses
Neomycin is overwhelmingly used as a topical preparation. It can also be given orally, where it is usually combined with other antibiotics. Neomycin is not absorbed from the gastrointestinal tract, and has been used as a preventative measure for hepatic encephalopathy and hypercholesterolemia. By killing bacteria in the intestinal tract, it keeps ammonia levels low and prevents hepatic encephalopathy, especially prior to GI surgery. It is not given intravenously, as neomycin is extremely nephrotoxic (it causes kidney damage), especially compared to other aminoglycosides.
Spectrum
Neomycin has a broad spectrum of effect, killing both gram-positive and gram negative bacteria. It is relatively toxic to humans, and some people have allergic reactions to it.
Neomycin is used in the laboratory in agar plates when culturing organisims anaerobically. Neomycin stops the growth of gram-negative bacilli and staphylcocci, allowing Streptococcus species to grow more abundantly.
History
Neomycin was discovered in 1949 by the microbiologist Selman Waksman. It is produced naturally by the bacterium Streptomyces fradiae.