About Gentamicin Aminoglycoside antibiotic. Mechanism of Action of Gentamicin Gentamicin exerts its bactericidal action against gram negative organisms & some of gram positive organisms by inhibiting bacterial protein synthesis. The process involves 1. Penetration of bacterial cell membrane & binding directly to the bacterial ribosome, 2. Misleading of m-RNA codon by bacterial ribosome, 3. Formation of peptide chains with wrong amino acid sequence which gets incorporated into bacterial cell membrane and alters its permeability, 4. Bacterial cell lysis. Some bacterial strains resistant to other amino glycosides are sensitive to Gentamicin.