Tobramycin drug molecule. Ball-and-stick molecular model of tobramycin, an aminoglycoside antibiotic. It is used to treat various types of bacterial infections, particularly those caused by Gram-negative bacteria. It is particularly effective against species of Pseudomonas. It works to kill bacteria via inhibiting their ability to synthesise proteins. Its chemical formula is C18H37N5O9. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (black), oxygen (red), and nitrogen (blue).