Used as an antibiotic to treat serious bacterial infections, particularly those caused by gram-negative bacteria. Effective in cases where other antibiotics fail due to resistance. Commonly used in hospitals for treating infections in the lungs, urinary tract, skin, and bloodstream. Also used in managing infections in immunocompromised patients. Often reserved for severe infections due to risk of side effects like kidney and hearing damage. Can be administered intravenously or intramuscularly.