Question: There is a new drug called Staphefekt that is said to replace antibiotics for drug-resistant bacteria. How does this work? And won't the bacteria become resistant to this as well?

David Foley answered on 12 Nov 2014:

Hi Elliot. I’ve a very quick look into this quite interesting approach.

It works by using a slightly modified verison of a natural enzyme that is produced by viruses that infect bacteria (yes, bacteria get sick too!). This enzyme damages the cell wall of the bacteria. The viruse uses this to gain access to the bacterium, but higher doses rupture the bacterium’s cell wall completely which kills it.

Becuase the virus has evolved with the bacteria over the millenia, it is thought that the target for the enzyme cannot be easily changed by the bacteria evolving, so the risk of resistance is low. Indeed, to date they have seen no evidence of resistance in the lab whereas most antibiotics will eventually show such resistance. This probably means that, if used properly, resistance in the real world is very unlikely.

The drawbacks of this method are that:

1. Because it uses a very specific viral enzyme it will only kill specific bacteria, in this case Staphyloccous aureus. It is not, therefore a broad spectrum antibiotic as yet, although the company calims they are working on it.

2. Because it is an enzyme, it will be very challenging to formulate it so that it can be administered by mouth and reach all of the body. Enzymes are usually destroyed in the stomach and do not get absorbed intact by the gut. People have been trying for decades to make oral insulin, for example, with very limited success. Again, the comapny say they are working on it, but for now this drug is limited to treating bacterial infections of the skin, mouth etc.

However, the whole concept of using such viral enzymes is fascinating and could well herald a revolution in antibiotic treatment, especially if a solution to the oral delivery problem can be found.

Hope this helps – sorry for typos!