Caution in the modern era requires protecting the antibiotic arsenal
Medicine has long understood that preventing harm is among its highest callings — but researchers at Charles University in Prague now warn that the instinct to protect can itself become a source of danger. By prescribing antibiotics to healthy people as a precaution, clinicians are quietly eroding the very drugs they hope to preserve, accelerating a global resistance crisis that claims hundreds of thousands of lives each year. The paradox is as old as intervention itself: the cure, applied too freely, becomes part of the disease.
- Preventive antibiotic prescribing has expanded far beyond what clinical evidence supports, exposing vast numbers of healthy people to drugs that offer them little benefit and the broader population lasting harm.
- In one striking case, epidemiological data show that roughly 580 healthy people must be treated with critical WHO-flagged antibiotics to prevent a single secondary streptococcal infection — a ratio that lays bare the scale of the imbalance.
- Four common clinical scenarios — viral pneumonia, STI prevention, C. difficile prophylaxis, and Group A Strep household contacts — have become flashpoints where caution-driven prescribing is actively breeding resistant pathogens.
- Researchers are calling for a fundamental reorientation: prophylaxis reserved only for high-risk individuals, narrow-spectrum drugs chosen over broad ones, and treatment durations cut to the minimum safely possible.
- The trajectory is urgent — drug-resistant infections are already rising, and each unnecessary antibiotic course further depletes an arsenal that, once lost, cannot easily be rebuilt.
Doctors face a sharpening paradox: the act of preventing infection can make infections harder to treat. Antibiotic prophylaxis — giving drugs to healthy people before illness strikes — is a legitimate tool, but researchers at Charles University in Prague are warning that it has spread far beyond what evidence justifies. Their commentary, published in Clinical Microbiology and Infection, argues that prescribing antibiotics "just in case" is quietly accelerating the global antimicrobial resistance crisis.
The core problem is one of selective pressure. As infectious disease specialist Dr. Marek Stefan explains, exposing hundreds of healthy individuals to antibiotics in order to prevent a single secondary infection places enormous strain on the human microbiome, creating conditions in which resistant bacteria adapt, survive, and pass on their defenses. The math is unforgiving: every unnecessary course is an opportunity for pathogens to evolve.
The researchers examine four clinical scenarios where this plays out — antibiotic use in viral pneumonia, post-exposure STI prevention with doxycycline, vancomycin for C. difficile prophylaxis, and treatment of household contacts of invasive Group A Streptococcus. That last case is particularly stark: Dutch epidemiological data show roughly 580 healthy contacts must be treated to prevent one secondary infection, often using antibiotics the WHO has designated as critical medicines to be protected.
Co-author Dr. Marcela Krutova is direct about the remedy: indications must be strictly evidence-based, drug selection should favor narrow-spectrum antibiotics from the WHO Access group, and treatment duration should be as short as safely possible. In an era of rising resistance, the researchers argue, true medical caution no longer means prescribing freely — it means withholding medication until the evidence genuinely demands it. The alternative is watching life-saving drugs lose their power precisely when they are needed most.
Doctors face a paradox that grows sharper each year: the very act of preventing infection can make infections harder to treat. Antibiotic prophylaxis—giving antibiotics to healthy people to ward off illness before it starts—is a legitimate medical tool. But researchers at Charles University in Prague are sounding an alarm about how casually the practice has spread, warning that the habit of prescribing antibiotics "just in case" is quietly accelerating the global crisis of antimicrobial resistance.
The concern, laid out in a new commentary published in Clinical Microbiology and Infection, hinges on a troubling imbalance. When antibiotics are used to treat confirmed infections, they face strict oversight. But when they're used preventively, that caution evaporates. The medical community has expanded prophylactic prescribing far beyond what evidence supports, the researchers argue, trading long-term drug effectiveness for short-term peace of mind.
Dr. Marek Stefan, an infectious disease specialist at Charles University and one of the paper's authors, frames the problem in ecological terms. "When we expose hundreds of healthy individuals to these drugs simply to prevent a single secondary infection, we place immense selective pressure on the human microbiome," he explains. "This inevitably accelerates the emergence of resistant pathogens." The math is stark: each unnecessary course of antibiotics given to a well person creates an opportunity for bacteria to adapt, to survive, to pass resistance genes to the next generation.
The commentary examines four specific clinical scenarios where this dynamic plays out. Doctors routinely give antibiotics for viral pneumonia, even though the drugs offer limited benefit and expose large populations to unnecessary pressure. Doxycycline is increasingly prescribed after potential exposure to sexually transmitted infections. Vancomycin is administered to prevent Clostridioides difficile infections. And antibiotics are given to household contacts of people with invasive Group A Streptococcus. In that last case, epidemiological data from the Netherlands reveal the scale of the problem: roughly 580 healthy contacts must be treated to prevent a single secondary infection. Many of those treatments use antibiotics like azithromycin or rifampicin—drugs the World Health Organization has flagged as critical medicines that should be protected, not squandered.
The researchers argue that the medical instinct to err on the side of caution has become counterproductive. In an era of rising drug resistance, true caution means something different: it means withholding medication unless robust clinical evidence justifies it. Dr. Marcela Krutova, a medical microbiologist and co-author, is direct about what needs to change. "Indications should be strictly evidence-based, antibiotic selection should favor narrow-spectrum antibiotics from the WHO Access group, and the duration of administration should be as short as possible." In other words, reserve prophylaxis for the people who truly need it, use the gentlest effective drug, and stop as soon as safely possible.
The stakes are not abstract. Drug-resistant pathogens kill hundreds of thousands of people globally each year, and the toll is rising. Every unnecessary course of antibiotics given to a healthy person chips away at the arsenal available to treat the sick. The researchers from Charles University are offering healthcare systems a blueprint: tighten the criteria for prophylaxis, choose narrow-spectrum drugs over broad ones, and resist the creeping normalization of "just in case" prescribing. The alternative is watching these life-saving drugs lose their power precisely when they're needed most.
Notable Quotes
When we expose hundreds of healthy individuals to these drugs simply to prevent a single secondary infection, we place immense selective pressure on the human microbiome. This inevitably accelerates the emergence of resistant pathogens.— Dr. Marek Stefan, infectious disease specialist, Charles University
Indications should be strictly evidence-based, antibiotic selection should favor narrow-spectrum antibiotics from the WHO Access group, and the duration of administration should be as short as possible.— Dr. Marcela Krutova, medical microbiologist, Charles University
The Hearth Conversation Another angle on the story
Why does it matter if we give antibiotics to healthy people? Isn't prevention always better than cure?
Prevention is better—but only if it actually prevents something. The problem is we're treating hundreds of healthy people to stop one infection that might never happen. Meanwhile, each person's body becomes a training ground for resistant bacteria.
So the bacteria in my gut adapt to the drug?
Exactly. And then those adapted bacteria can spread to others, or persist in you and cause problems later. We're essentially creating the very resistance we're trying to avoid.
The article mentions Group A Strep contacts. Why treat 580 people to prevent one case?
Because we can't predict which of those 580 will actually get sick. But the cost is that all 580 are exposed to the drug. It's a numbers game where the math doesn't work in our favor anymore.
What would change if doctors stopped doing this?
We'd preserve the effectiveness of these drugs for people who actually have infections. We'd also reduce the selective pressure that drives resistance. It's about using antibiotics more deliberately, not less.
Is this a problem with doctors being careless?
Not careless—cautious, actually. Doctors want to prevent harm. But caution in the antibiotic era means something different now. It means accepting some risk to prevent a bigger one.