Zosyn Injection 4.5 gm (PIPERACILLIN-4GM + TAZOBACTAM-500MG) belongs to the ‘Antibiotics’ class of drugs, primarily used to treat bacterial infections. It is used to treat various hospital-acquired and ventilator-associated pneumonia, urinary tract infections, intra-abdominal infections, skin and soft tissue infections (like diabetic foot infections) and uterine infections. Bacterial infection occurs when harmful bacteria grow in the body and causes illness. It can infect any part of the body and multiply very quickly.