Ampicillin

Ampicillin, semisynthetic antibiotic that is a derivative of penicillin, used to treat a wide range of bacterial infections. Ampicillin can kill some bacteria not effectively killed by other forms of penicillin, and is used to treat severe ear and sinus infections, meningitis in children, and various infections of the urinary, respiratory, and intestinal tracts. Among the microorganisms susceptible to ampicillin are Salmonella, several species of which cause a type of food poisoning, and Salmonella typhosa, the cause of typhoid fever. Although penicillin is still widely prescribed, its effectiveness has decreased somewhat since its introduction in 1961, because certain bacteria have begun to develop resistance to it.

See also: Penicillin.