Would it be possible to introduce a population of bacteria that are not as resistant to antibiotics in order to increase the competition of resources in the space?
I'm sure I read about something like this years ago, and I have, on occasion, tried to search for a source, but I've never been able to find one. I have a feeling it was a chapter in a book rather than an article or a paper. If anyone knows, please direct it my way. It's an interesting idea, and it wouldn't even require the introduction of a new population as this population already exists.
The hypothesis, very basically, goes along these lines:
You have a wild population of bacteria, say,
Staphylococcus aureus. To this population, you introduce a penicillin based antibiotic. Now, this penicillin antibiotic might wipe out the majority of these bacteria, but there will be a few which are resistant to it due to various random genetic mutations. There are various ways for a bacterium to be resistant to an antibiotic - it can produce an enzyme which breaks down the antibiotic, it can develop a new metabolic pathway to bypass the one affected by the antibiotic, it can actively pump the antibiotic out of itself, it can alter the receptor or protein which the antibiotic binds to, etc. In the case of
S. aureus and penicillins, it is the last of these.
Now, this altered protein, while being more resistant to the effects of the antibiotic, is less effective and efficient than the non-resistant wild type. The evolutionary selection pressure for the the last however many millions of years and trillions of generations has been efficiency, and so the wild type protein is hugely efficient. Now, however, you have changed the selection pressure to be that of penicillin resistance. The less efficient but more resistant protein is now favored. Because it is less efficient, the cell has to spend more energy to produce it, and dedicate more of its resources to using it. Over time, with the ongoing penicillin resistant selection pressure, the protein evolves to become even better at withstanding penicillin, but at further cost to its overall efficiency.
If we removed the selection pressure of the antibiotic, then the wild type once again becomes the favored protein - it is more efficient in the absence of the antibiotic, after all. Over time the wild type bacteria, which is more energy efficient, would out compete the penicillin resistant bacteria for resources, as the penicillin resistant population is spending additional energy and resources on manufacturing a sub-optimal protein. The resistant population would essentially be out-bred to near extinction by the wild type population.
This has been proven in a lab setting - a wild type population will out compete an antibiotic resistant population in the absence of the antibiotic, as the resistant population has to spend additional energy and resources on its now unnecessary resistance. If we could completely ban penicillins from being used in every country around the world for a number of years, the hypothesis is that penicillin resistance would more-or-less disappear, and they would again become the wonder drug that they were back in the 40s and 50s. The problem being that this is essentially unworkable on a global scale. With the ubiquitousness of international travel, a single surviving population of penicillin resistant organisms would rapidly move around the world and recolonise areas where they had previously been eradicated.