Bactroban is a medical cream that is applied topically to treat various skin conditions.It specifically treats infections caused by Staphylococcus aureus (MRSA) which is resistant to methicillin. This medication also comes in an ointment that can be applied inside the nose to help prevent the infection from spreading to other people. This nasal ointment alternative is especially effective because it is meant for patients who bacteria have become resistant to other antibiotics. Bactroban works by blocking the action of the enzyme isoleucyl-tRNA synthetase that can be found within the bacteria. This enzyme is extremely important to the bacteria because it helps in making proteins. Taking away the bacteria's ability to make proteins causes it to die.