Why antibiotic resistance matters even if you feel healthy
Antibiotics are often thought of as something people need only when they are sick. But according to Rajeev Misra, a professor in Arizona State University's School of Life Sciences, antibiotic resistance is a problem that affects everyone, including people who feel perfectly healthy.
Misra recently published a comprehensive review examining how bacteria become resistant to antibiotics through genetic mutations. He says most people will need antibiotics at some point in their lives, even if they rarely get sick.
“Most people will take antibiotics at some point in their life,” Misra said.
Antibiotics are commonly prescribed as a precaution during surgeries and some dental procedures, not because a patient is infected, but to prevent bacteria from causing infections while the body is vulnerable. During surgery, bacteria can enter the body through incisions or medical instruments, and antibiotics help reduce that risk.
Doctors often use antibiotics broadly during these situations to prevent infections before they start. While this approach saves lives, it also contributes to the growing global challenge of antibiotic resistance.
In 2021, antibiotic resistance was linked to more than one million deaths worldwide. Misra says that number reflects how widespread and complex the problem has become.
Resistance can develop for many reasons, including overprescription of antibiotics, taking antibiotics for viral infections where they have no effect and frequent antibiotic use in hospital settings. Hospitals, Misra explained, can become environments where resistant bacteria thrive because antibiotics are used so often.
At the heart of Misra’s research is the idea that antibiotic resistance is an evolutionary process. Bacteria constantly change at the genetic level. When antibiotics are used, they kill most bacteria, but those with mutations that help them survive remain and reproduce, gradually making the population more resistant.
“Mutations are means for bacteria to survive and evolve,” Misra said. “Antibiotics are simply one of those stress conditions.”
Once resistance is encoded in the genome, it can be passed down to future generations of bacteria. That evolutionary process is especially accelerated when antibiotics are misused, such as when people stop taking them early because they feel better.
When antibiotics are taken inconsistently, they may kill most of the bacteria but not all of them. The remaining bacteria are then exposed to low levels of antibiotics, which Misra says can actually encourage mutations that allow bacteria to tolerate those drugs in the future.
“That mutation gets fixed in the population,” he said. “And then, the next time you get sick, you won’t get rid of them.”
Completing a full course of antibiotics helps ensure that nearly all bacteria are eliminated, leaving little opportunity for resistant survivors to emerge.
Misra’s paper also highlights strategies scientists are using to slow the spread of resistance. One promising approach is combination therapy, where two or more antibiotics are used at the same time to target different bacterial systems. The odds of a single bacterium developing resistance to multiple drugs simultaneously are extremely low.
Another approach involves pairing antibiotics with compounds called efflux pump inhibitors. These inhibitors block bacterial “pumps” that normally expel antibiotics from the cell, allowing the drugs to remain inside long enough to be effective.
Together, these strategies aim to make antibiotics harder for bacteria to evade.
Despite these advances, Misra is clear that antibiotic resistance cannot be eliminated entirely.
“We know that bacteria will evolve and mutate,” he said. “And we know that antibiotics will continue to be used because they can be lifesaving.”
Because of that, the goal is not to stop resistance completely, but to slow it down. Misra says doing so requires a multipronged approach that includes scientific research, better diagnostics, physician and patient education, improved sanitation and more careful use of antibiotics in medicine and agriculture.
He hopes nonscientists come away from his research with understanding rather than fear.
“The idea is not to scare people,” Misra said. “But to understand that genetic mutation is something that will not go away.”
By understanding how antibiotic resistance develops, Misra says scientists and physicians can design better treatments, and patients can make more informed choices. Without that understanding, infections are treated blindly, increasing the risk that today’s lifesaving drugs will stop working tomorrow.