Gentamycin belongs to the group of aminoglycosides and acts bactericidal against mainly Gram-negative bacteria like E. coli, Klebsiella, Pasteurella, and Salmonella spp. The bactericidal action is based on inhibition of bacterial protein synthesis. Moreover, it is active against Campylobacter fetus subsp. jejuni and Treponema hyodysenteriae. Gentamycin may be active against bacteria which are resistant to other amino-glycoside antibiotics (like neomycin, streptomycin, and kanamycin). After intramuscular administration, within 30-60 minutes maximum serum concentrations are obtained. Gentamycin is excreted mainly by the kidneys, resulting in high concentrations of the active compound in the urine. Indications: Gastrointestinal.