Ticarcillin is a carboxypenicillin. It is almost always sold and used in combination with clavulanate as ticarcillin/clavulanic acid. Because it is a penicillin, it also falls within the larger class of beta-lactam antibiotics. Its main clinical use is as an injectable antibiotic for the treatment of Gram-negative bacteria, particularly Pseudomonas aeruginosa. It is also one of the few antibiotics capable of treating Stenotrophomonas maltophilia infections. Ticarcillin is a carboxypenicillin. It is almost always sold and used in combination with clavulanate as ticarcillin/clavulanic acid. Because it is a penicillin, it also falls within the larger class of beta-lactam antibiotics. Its main clinical use is as an injectable antibiotic for the treatment of Gram-negative bacteria, particularly Pseudomonas aeruginosa. It is also one of the few antibiotics capable of treating Stenotrophomonas maltophilia infections.