Ask the Expert: You are about to enter the post-antibiotic age of medicine
The first commercially available antibiotics revolutionized human health. A severe bacterial infection, which used to be a death sentence, was now curable by taking a few pills. But from where did the compound responsible for killing or disabling the bacteria come? When I first ask my microbiology students this question, many know about Alexander Fleming and his accidental discovery of penicillin.
The original bacteria fighter: microbes
However, the real answer is other microbes, primarily yeasts, molds, and bacteria. Almost all of the commercially available antibiotics were first made by microbes as part of an evolutionary arms race.
Microbes have to compete for limited resources. Imagine a microbe that develops a chemical compound that kills its competitors in the nearby vicinity. That’s a highly desirable microbial weapon for the microbe that wields it. However, co-opting these weapons may be our undoing and cause us to run headfirst into the post-antibiotic age of medicine, where bacteria are unaffected by all commercially available antibiotics.
When what saves us can hurt us
The most pressing problem with using microbe-derived compounds as antibiotics is that the bacteria making the compound (our original microbe warrior killing its nearby neighbors) is, of course, already resistant to its own chemical weapon—which means that antibiotic resistance exists in nature and can spread to other bacteria living in the same ecosystem. New mechanisms of resistance can also appear randomly. Bacterial genomes change frequently, and the right change in the right place can render the antibiotic ineffective, making that bacterium (and all the future bacteria it spawns) resistant.
Because they are more likely to survive when antibiotics are present, bacteria can build an arsenal of resistance mechanisms, which poses a threat to public health if the resistant bacterium causes disease. There are now disease-causing bacteria that are resistant to every commercially available antibiotic.
Antibiotic resistance is not a new problem. The first penicillin-resistant bacterium was discovered before penicillin was commercially available. What makes antibiotic-resistant bacteria a crisis now is the lack of novel (or new) antibiotic treatments.
Can we save ourselves from antibiotic-resistant bacteria?
Research in my laboratory has turned to the ultimate antibiotic: the immune system. It’s the immune system that actively fights the infection. Antibiotics are a weapon to help win the fight. Small proteins called antimicrobial peptides (AMPs) that disable or kill bacteria are an important part of many immune systems. We investigate a specific class of AMPs that poke holes in bacteria, and we want to understand the interaction between these AMPs and the bacterial surface at the molecular level. This information might be used to design new antibiotic compounds, or it might be added to current antibiotics to overcome certain types of resistance, reviving the ability of our current antibiotic arsenal.
In the meantime, we all share a responsibility to be good stewards of antibiotic use, looking to limit antibiotic usage wherever possible in health care, agriculture, and consumer products. These actions might not stop bacteria from becoming resistant, but good stewardship can slow it down, giving scientists and physicians time to prepare a new set of weapons in our fight against antibiotic resistance.
Professor Volle holds a Ph.D. in molecular and cellular biology and biochemistry from Brown University and served as a postdoctoral fellow at the National Cancer Institute. She joined the Cornell College faculty in 2019.
