Question: Do you ever think it will be possible to produce an antibiotic which does not cause some bacteria to become resistant?

Robert Hampson answered on 10 Nov 2014:

Great question!!

All things that cause disease in humans or animals are known as pathogens. Some bacteria live and thrive by causing infection in either animals or humans. In fact, they often use the inside of human cells to breed. They are called obligate pathogens (as they are obligated to be pathogens, they cannot survive without causing disease). If we prevent these bacteria from causing infections, then there will always be an evolutionary pressure to overcome whatever we have done to prevent it. At this point, there is a race to eradicate the disease or watch as our drug becomes useless. The only success story I know in this area is Smallpox which was eradicated in the ’50s using a vaccine (it’s also a virus so antibiotics wouldn’t work anyway).

However, there are some bacteria which only infect people when the opportunity arises (they are called opportunistic pathogens). In this case, it may be theoretically possible to produce drugs which cause an evolutionary pressure to not infect human hosts. This may be a path to antibiotics (or antiinfective agents) which prevent disease and remain useful for a very long time.

Also, opportunistic pathogens often live on you perfectly happily without causing a problem so are more likely to come into contact and be able to become resistant to antibiotics, obligate pathogens are only really present when making you ill so they have less opportunity to become resistant but more reason to do so.

As you can probably see, there are many things to consider and still too many unknowns to be able to predict whether an unresistable antibiotic is possible. Even if we though we had made one, it only takes one bacteria for us to be disproved and we would have to go back to the drawing board!