Piperacillin Products | Cleanchem - Piperacillin is a broad-spectrum penicillin antibiotic used to treat a wide variety of bacterial infections, particularly those caused by Gram-negative organisms. It works by inhibiting the bacterial cell wall synthesis, leading to the destruction of the bacteria. It is often used in hospital settings to treat serious infections such as pneumonia, intra-abdominal infections, and urinary tract infections.