Zavicefta is an antibiotic used in adults to treat the following infections:• complicated (difficult to treat) infections of the tissues and organs within the belly (intra-abdominal infections)-• complicated (difficult to treat) infections of the urinary tract (structures that carry urine), including pyelonephritis (kidney infection)-• infections of the lungs that are caught in hospital (hospital-acquired pneumonia), including ventilator-associated pneumonia (pneumonia caught from a ventilator, which is a machine that helps a patient to breathe)-• infections caused by gram-negative bacteria (types of bacteria) when other treatments might not work.