Unintended Consequences: Antibacterial soaps, disinfectants, and antiseptics don’t kill bad bacteria. Instead, their use results in more of them
It seems that we humans have this ability to get things not just wrong, but dangerously backwards.
In one of the more popular stories in the New York Times this week, we learn that we cannot sustain weight loss by dieting and, more troubling, that dieting will actually cause you to gain weight and even to become obese. The reason is our internal biology: in response to fewer calories coming in, our brain declares a “state of emergency” and issues orders to our body to: burn less calories, increase the release of hunger-inducing hormones and, make eating more rewarding. Ouch!
And in our homes, yet another counterintuitive and unintended event is taking place too: we are turning our homes into antibiotic-resistant bug-filled tombs, leaving us more vulnerable than ever to harder-to-treat illness. We even work hard at this, daily, through our increased use of antibacterial containing household products: soaps and shampoos, antiseptics, and disinfectants. This practice will not only not kill the bad bugs, it will create the very conditions that allow them to proliferate and spread.
It goes like this. In every population of bugs in our homes and on us, most are susceptible to our killing agents — an antibiotic drug or an antibacterial chemical in a cleaning product. But there are some bugs that aren’t susceptible. These ones we call resistant, i.e. resistant to the killing agent. So after we use our chemical “weapon” and kill off the susceptible population, the surviving resistant ones have all that extra real estate to reproduce and spread. Which they do at a rapid clip: they can produce a new generation in an hour (we take around 20 years), thus producing dozens of new generations overnight, each one resistant to that antibacterial weapon. This diagram nicely illustrates how it works
But not only is this new generation bacteria resistant to the particular drug or cleaning agent used against it, it also develops something called “cross-resistance”: the ability to resist many different kinds of drugs or antibacterial agents. It becomes what in common parlance is referred to as a “superbug.” That’s generally accepted science these days, a conclusion long-ago reached by Dr. Stuart Levy, MD, Director, Center for Adaptation Genetics and Drug Resistance, Tufts University, and explained in his book The Antibiotic Paradox: How the Misuse of Antibiotics Destroys their Curative Powers.
In other words, the more we clean our homes with these products the more we surround ourselves with bugs that our antibiotic drugs having less and less effect on. So if we succumb to infection by them, we guarantee ourselves a longer and more difficult to treat illness, or one that can’t be treated at all. For example, Dr. Levy reports that exposing low-level resistant methicillin-resistant staph aureus (MRSA) bacteria to an antibacterial agent (similar to chemicals used in disinfectants), increased that MRSA’s resistance by 10-fold to antibiotics. So with an aging demographic and an increasing emphasis on home care versus hospital care, it matters how we clean our homes.
The devil is in the detail, warns Dr. Levy. Be on the lookout for the 2 suspects in the household cleaners that drive the proliferation of these resistant bugs: triclosan and triclocarbon. Read the labels, Dr. Levy says, and steer clear of these 2 guys unless your doctor says otherwise and explains how to use them. For instance, you would wash your hands for 2 or 3 minutes, not 3 or 5 seconds, as we typically do. Dr. Levy advises normal soap and water for hand washing; and peroxides, and chlorinated bleaches, for use as antiseptics and disinfectants, respectively. In the case of hand washing, the addition of a cleaning alcohol “produces a significant additive effect,” he says.