Science Interviews

Bacteriophage (phage) Therapy

Professor Nick Mann

Nick - Bacteriophages are viruses that infect bacterial cells and kill them. The word bacteriophage literally means 'bacteria eater.'

Chris - How do they grow?

Nick - Phages attach to bacteria and inject their genetic material into the cell. The genetic material makes more copies of itself, bursts the cell open and goes into the environment. One phage gives rise to, say, 100 new phages, which inject their genetic material into 100 more bacteria and so on. This amplifying process is one of the great benefits to phage therapy. Putting one
phage into an infected wound will lead to a chain reaction that expands until all the bacteria are dead. This is in contrast to antibiotics, which become less concentrated and less effective the longer and further they travel into the body.

Chris - How would you give the phage to the patient?

Nick - More trails are needed before we can start administering phages to patients, but we will probably start by putting them on surface wounds. This could be achieved by impregnating wound dressings with the phages. Once the bacteria have gone, the phages also die out. Another avenue we are exploring with regards to MRSA is trying getting rid of it in the nose. The phages will be delivered through a plastic inhaler. So far, it has been tried out on a couple of student volunteers which remained negative for MRSA for the few days we looked at them. We are going to do longer controlled trails and are
desperately trying to get it into hospitals. If the nasal inhaler is given to visitors, staff, and patients, the levels of MRSA in hospitals will hopefully decrease.

Chris - Will the bacteria become resistant to the phages like they have to some
antibiotics?

Nick - The bacteria will become resistant, but phages are living and can mutate too. Therefore, the bacteria and phages will fall into an evolutionary arms race whereby both bacteria and bacteriophages will evolve methods to outwit the other. As long as phages can keep up, they will always be a threat to the bacteria.

December 2004