Azlocillin is primarily used as an antibiotic in the treatment of bacterial infections, particularly those caused by Gram-negative bacteria. It is effective against infections in the respiratory tract, urinary tract, skin, and soft tissues. Due to its broad-spectrum activity, it is often employed in cases where Pseudomonas aeruginosa is the causative agent, such as in patients with cystic fibrosis or severe hospital-acquired infections. Azlocillin is also utilized in combination with other antibiotics to enhance its efficacy and combat resistant bacterial strains. Its application is typically reserved for serious infections where other antibiotics may not be effective.