PIPDEL-T 1.125 injection is used to treat pneumonia and skin, gynecological, and abdominal (stomach area) infections caused by bacteria. Piperacillin is in a class of medications called penicillin antibiotics. It works by killing bacteria that cause infection. Tazobactam is in a class called beta-lactamase inhibitor. It works by preventing bacteria from destroying piperacillin.