As a penicillin group of beta-lactam antibiotics, Ampicillin is the first broad-spectrum penicillin, which has in vitro activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria, commonly used for preventing and treating bacterial infections of respiratory tract, urinary tract, middle ear, sinuses, stomach and intestines, bladder, and kidney, etc. caused by susceptible bacteria. It is also used to treat uncomplicated gonorrhea, meningitis, endocarditis salmonellosis, and other serious infections through administered by mouth, intramuscular injection or by intravenous infusion. Like all antibiotics, it is not effective for the treatment of viral infections.
Ampicillin functions by killing the bacteria or preventing their growth. After penetrating Gram-positive and Gram-negative bacteria, it acts as an irreversible inhibitor of the enzyme transpeptidase needed by bacteria to make the cell wall, which results to the inhibition of cell wall synthesis and eventually leads to cell lysis.