Is antibiotic resistance irreversible

Answer 1

In my opinion, a simple answer to this would be yes.

By using antibiotics or actively trying to kill bacteria, you are actively putting a selective process on that bacterial culture. When an antibiotic is first in use in a clinical setting, generally most (>99%) of the bacteria are susceptible to the antibiotic and therefore will die - however a very small number will have a slight variation (the range of resistance mechanisms are wide and diverse - from enzymes that can break the antibiotic down - to efflux pumps in the membrane that can actively pump the antibiotic out of the cell) that will allow them to survive.

This surviving "resistant strain" will then continue to grow and spread as the susceptible strain is continually selected against by the continued use of that antibiotic. This eventually leads to the resistant strain dominating the overall community, and so antibiotic resistance has become prevalent.

There are many type of antibiotic that act to kill bacteria in a variety of ways (penicillins break down bacterial cell walls, tetracyclines inhibit protein synthesis), so in the past when bacteria have become resistant to one type of antibiotic, we simply treated them with another type.

The difficulty of this is that it means we have continually selected for bacteria that are resistant to more and more types of antibiotic, leading to MDR (multi-drug resistance).

With a limited number of antibiotics available and the number of new antibiotics being discovered annually having decreased over the last decade, these MDRs are causing infections that are very difficult to treat.

As such, coming back to the question, no antibiotic resistance cannot be reversed because it is a natural for bacteria to adapt and evolve antibiotic resistance when antibiotic use in clinical settings provide a perfect selection process.

However, its not all doom and gloom. Many biotech and pharmaceutical companies have now realised that the future of antibiotics is to intelligently design molecules (drugs) that target antibiotic resistance, making these strains susceptible again, or even to develop drugs that bacteria can't gain resistance to due to their design.

P.S Antibiotic Resistance has also been observed in bacterial cultures that have been grown from soil samples obtained from permafrost thousands of years old (D'Costa et al 2011). Therefore antibiotic resistance has been present in numerous bacterial species well before humans started using antibiotics in a clinical setting.

A link to the D'Costa et al article can be found in related links.