Humans and bacteria are in a constant process of mutual accommodation. The discovery of antibiotics encouraged the conceit that we had reached the end of history with our microbial adversaries. We won, they lost, end of story.
It wasn’t quite that neat and simple, was it?
We ignored the reality that antibiotics have been around for a lot longer than humans. Bacteria had hundreds of millions of years to develop resistance to them. It took a couple of decades, but they dredged ancient resistance genes out of the soil (with an assist from modern livestock farming practices) and transferred them to human pathogens.
It’s a truism of infectious disease that new pathogens start off highly virulent, but lose their punch over time as we evolve adaptations that blunt their attacks. They still infect us, but no longer kill us quite so readily.
Looked at from the bacterial point of view, antibiotics were a highly virulent plague that destroyed and disrupted their way of life. Resistance is their adaptation, a way of finding accommodation and a new equilibrium.
The human side of the new equilibrium is our realization that antibiotics harm not only pathogens, but our commensal bacteria and thus ourselves. We are just beginning to understand that we rely on these bugs for the proper development and regulation of our immune, metabolic, and nervous systems. Antibiotic use, particularly in infancy, is associated with a host of modern disorders such as diabetes, asthma, obesity, and depression.
From The microbiota-gut-brain axis: neurobehavioral correlates, health and sociality
The transition from war to accommodation is far from complete, but here is what I think the new equilibrium will look like:
- We pay more attention to public health facilities in our cities and to hygiene in our hospitals. Application of these boring but essential tasks has already led to a dramatic reduction in MRSA rates in UK hospitals. No tech fix was involved, just diligence and good management.
- We develop more narrow-spectrum antibiotics and rapid tests to identify infecting bacteria. These antibiotics are far less likely to disrupt the microbiome and to select for resistance genes within it.
- We develop alternative therapy modes, such as antivirulence therapies that disarm, rather than kill bacteria. These therapies will also be less disruptive to our microbiomes and are less prone to inducing resistance.
- We develop rapid tests to distinguish bacterial from viral infections, and stop prescribing antibiotics for the latter.
- We stop feeding subtherapeutic doses of antibiotics to livestock.
In this new arrangement, bacterial infections still happen, but less frequently. Some of them are resistant to one or more antibiotics, but this is less frequent – and less important. We will treat them with appropriate antibiotics and antivirulence therapies that kill and neutralize only the pathogens. Bacterial infections are not eliminated, but they are controlled at an acceptable level. Civilization does not collapse under the onslaught of invading barbarian bacteria.
The future of antibiotics is that we use them not as weapons to crush an adversary but as tools to manage a relationship. We will all be much happier with this arrangement.