Antibacterial soap may be breeding superbugs

Modern medicine is wildly successful at stopping infections that breach the body’s defenses. But far more lives have probably been saved by basic hygiene and clean water that prevent them in the first place.

Good hygiene has virtually eliminated once-feared diseases like cholera, typhoid and dysentery in the developed world by breaking the chain of disease transmission. If the rest of the world had greater access to it, the World Health Organization estimates 1.4 million deaths could be prevented each year.

That’s why readers of BMJ, formerly the British Medical Journal, voted the “sanitary revolution” the greatest medical advance since 1840, ahead of antibiotics and anesthesia.

Hygiene not only saves lives. It sells. Since the 1950s, companies have been adding “antimicrobial” compounds to soaps, touting their effectiveness at killing “99.9%” of germs.

These antimicrobial soaps are mostly hygiene theater: Scientists say plain soap and water is just as effective. Worse, these unnecessary compounds may be contributing to a newer problem: resistance to lifesaving antibiotics.

The coronavirus pandemic supercharged the use of antimicrobial products, despite their ineffectiveness against a largely airborne disease. Their active ingredients are now found in hand soap, laundry detergent, cosmetics and more — plus the blood and breast milk of many Americans.

Here’s why plain soap and water remain your best bet against colds and germs — and when disinfecting makes sense.

Antimicrobial overkill

Skim your grocery store’s cleaning aisle and you’ll find antimicrobial soaps claiming to kill “99.9% of bacteria.” Plain soap a few feet away offers a similar promise to “wash away” germs.

Both claims are true, for different reasons.

Soap molecules have two ends: one that loves oil and one that loves water. The oil-loving end breaks up oily grime and, like a little crowbar, pierces the exterior membrane that encloses many germs. The water-loving end then ensures everything goes down the drain with the rinse water.

Soap, in other words, mostly removes rather than kills. Antimicrobial chemicals just focus on the latter: The ingredients — often a quaternary ammonium compound like benzalkonium chloride that are also known as “quats” — kill microbes directly, typically by rupturing their external membrane.

The end result, however, is virtually identical: Both plain soap and antimicrobial products dispatch the offending bacteria or viruses, reducing your chances of getting sick. In fact, decades of studies have found no difference in illness between homes that use antimicrobial products and those that don’t.

A 2007 peer-reviewed analysis of 27 studies in Clinical Infectious Diseases found that triclosan, a powerful antimicrobial, was “no more effective than plain soap” at preventing symptoms of infectious illness or lowering bacterial levels on people’s hands. In laboratory studies, triclosan-resistant bacteria show increased resistance to antibiotics, evidence that antimicrobials in soaps are not just ineffective, but could contribute to the evolution of superbugs.

“There was no independent, peer-reviewed evidence that those soaps removed more pathogenic bacteria than plain soap in a typical hand-washing situation, or reduced illness in households,” said Rebecca Fuoco at the Green Science Policy Institute, a nonprofit group seeking to reduce toxic substances in products and the environment. “It was just marketing.”

In 2016, the Food and Drug Administration considered banning these potent biocides for home use, but decided not to do so. The agency did ban 19 active ingredients, including triclosan, from home antiseptic wash products. It found manufacturers had not proved these antimicrobial ingredients were safe for daily, long-term use or more effective than plain soap.

But the FDA left a crucial loophole: The industry got one year to prove the safety and effectiveness of three other chemicals that could replace triclosan — chloroxylenol and two compounds known as “quats,” benzalkonium chloride and benzethonium chloride. That initial 12 months of regulatory purgatory has long expired, but the “deferrals” have been extended for a decade, despite growing evidence of health risks. More than a third of the U.S. disinfectant market now have this new generation of antimicrobial products.

Fuoco and others warn that these powerful chemical disinfectants are accumulating in our bodies and the environment, where they may potentially contribute to antimicrobial resistance. That’s the process by which microbes become resistant to compounds such as antibiotics, disarming one of the most powerful weapons of modern medicine. Microbes have been seen in lab experiments to evolve defenses against antimicrobials that also confer resistance to antibiotics used to treat infections.

The World Health Organization warns that 1 in 6 common bacterial infections are now resistant to standard antibiotics, a 40% increase between 2018 and 2023. Resistant infections caused about 1 million deaths annually between 1990 and 2021, a figure projected to double by 2050.

The global fight against antimicrobial resistance has largely focused on managing use of antibiotics used in health care and agriculture, the problem’s main drivers. Fuoco argues that household products containing quats and other antimicrobial compounds in hand soaps, disinfecting wipes and sprays, laundry sanitizers, plastics, textiles and personal care products may be doing the same.

While there’s still some scientific uncertainty about whether biocides are driving resistance in human pathogens in homes, evidence from the lab suggests they share similarities to other sources of microbial resistance.

How should we stay clean without potentially breeding superbugs?

Fuoco frames it as a no-regrets decision: “You have the major U.S. and world public health authorities all look at the science and agree that there’s no benefit, only risks of these soaps,” she said.

What you should do instead

We don’t need — and should not have — sterile homes. Bacteria are everywhere and our microbiome, the community of microorganisms that live on and inside our bodies, depends on them being around us. The vast majority are benign or beneficial, and even keep nasty pathogens in check.

Plain soap and water remain the first line of defense to stop the transmission of potential pathogens in their tracks, at home, at school or elsewhere, Theresa Michele of the FDA’s Division of Nonprescription Drug Products previously told STAT News.

“We can’t advise this enough.” Wetting your hands and lathering for about 10 to 20 seconds before drying removes virtually all common bacteria and viruses as effectively as any biocide, or more effectively for some viruses.

Canadian health officer Bonnie Henry gave some sound advice during the pandemic: “Wash your hands like you’ve been chopping jalapeños and you need to change your contacts.”

Disinfection, which is less intense than sterilization, makes the most sense when you need to eliminate something uniquely virulent or risky. That’s typically when a surface is contaminated with bodily fluids, raw meat, when someone in the household is immunocompromised, or when you suspect someone has a stomach bug or diarrhea (often a persistent norovirus).

In those situations, health authorities such as the Centers for Disease Control and Prevention recommend a two-step process: Clean with soap and water to remove dirt and grime first, then use an Environmental Protection Agency-registered disinfecting product or a diluted bleach solution to kill any lingering pathogens. The bleach eventually breaks down into salt, water and oxygen.

For Maya Nadimpalli, an assistant professor at Emory University’s Rollins School of Public Health who studies microbial resistance, disinfection at home is rarely the point. She and her husband, a research immunologist, embrace the hygiene hypothesis, the idea that early exposure to routine microbes supports the development of children’s immune systems and reduces the risk of future allergic and autoimmune conditions. (You should still avoid exposure to severe disease, especially respiratory viruses for very young children).

Pursuing a sterile home can backfire. At home, Nadimpalli’s family typically uses the simplest soaps they can buy without fragrances or biocides. “We are hygienic but we are not into this 99.9 percent bacteria removal in everything we do,” she told me. “Developing a healthy immune system is the goal for our kids.”