Used primarily as an antibiotic to treat infections caused by susceptible Gram-negative bacteria, particularly Pseudomonas aeruginosa. It is effective in respiratory, urinary tract, and systemic infections, especially in immunocompromised patients or those with severe hospital-acquired infections. Due to its beta-lactam structure, it works by inhibiting bacterial cell wall synthesis. Often reserved for cases where other antibiotics are ineffective, it may be administered intravenously in clinical settings.