Used topically to treat bacterial skin infections due to its broad-spectrum activity against gram-positive and some gram-negative bacteria. Commonly found in creams, ointments, and eye drops for localized infections. Often combined with other agents like polymyxin and hydrocortisone to enhance effectiveness and reduce inflammation. Not used systemically due to high risk of nephrotoxicity and ototoxicity. Also used in cell culture and molecular biology as a selective agent to maintain genetically modified cells.