Pharmacology: Gentamicin is a bactericidal antibiotic that acts by inhibiting normal protein synthesis in susceptible micro-organisms. It is active against a wide variety of pathogens including Escherichia coli, Proteus species, Pseudomonas aeruginosa, Klebsiella-Enterobacter-Serratia group, Citrobacter species, Staphylococcus species, Streptococcus pneumoniae, Salmonella and Shigella species.