You know when your doctor prescribed a course of antibiotics and told you to take the entire prescription? You really should've listened. Thanks to millions of misused antibiotic prescriptions worldwide (how many half-empty bottles are in your medicine cabinet right now?), the bacteria you intend to kill are getting stronger. In fact, some bacteria -- like the MRSA superbug -- are immune to select antibiotics.
This happens through the process of natural selection. People take antibiotics to wipe out the bad bacteria causing an infection. But some bacteria are stronger than others, and if you don't finish the entire regimen of antibiotics, some bacteria will survive and pass on their resistance to antibiotics.
The evolution of drug-resistant bacteria is not just the result of prescription neglect. Antibacterial and antimicrobial soap, and other cleaning products you have in your bathroom and kitchen, are also responsible. Just as antibiotic prescriptions can be misused, so, too, can antibacterial products. When was the last time you washed your hands for the full 20 seconds that the national Centers for Disease Control suggests? Twenty seconds may not sound like much, but that's as long as it takes to belt out a full version of the ABCs.
Antibacterial and antimicrobial agents were created to prevent the spread of infection in hospitals. But companies began marketing these products to everyday consumers, too. As a result, more microbes are exposed to and develop resistances to these agents.
By using more antibacterial products, people may encourage bacteria to evolve and become more virulent than they were before. Overusing antibacterial products is now a major point of study within the field of pharmacoepidemiology -- the study of how people use medicines.
If antibacterial and antimicrobial products may be a threat to public health, why are are they still on store shelves? We'll get to that, but first let's look at how antibacterial products work -- or don't work.
Problems with Antibacterials
Through extensive advertising, manufacturers attempt to convince consumers that the're in battle with tiny invaders and must use specific antimicrobial products to protect their health. Studies suggest that the widespread use of antimicrobial chemicals may be causing these products to lose their effectiveness.
Triclosan is a common active ingredient found in modern antibacterial products. Most other engineered antibacterial agents are designed to attack organic functions of bacteria. Triclosan specifically inhibits the production of a fatty acid vital to life within bacterial cells. The problem is, bacteria that survive the introduction of Triclosan can mutate into a new strain that resists the antimicrobial chemical's effects.
How can bacteria resist the antimicrobial onslaught? Dr. Stuart B. Levy, of the Tufts School of Medicine in Boston, believes the answer lies in residual amounts of the agent that stick around after application. For those bacteria that survive, this residual soup is like one big sink-or-swim training camp. The bacteria mutate and adapt to ward off future attacks by their enemy. Microbiologists call this process selection -- those microbes that live are selected to go on to mutate and reproduce.
What's worse, some antibacterial agents go after the same physiology of bacteria that prescription antibiotics do. This means that if a particular strain of bacteria develops a resistance to an antibacterial agent in a household cleaner, it will also be resistant to similar attacks from prescription antibiotics. Microbiologists call this cross-resistance.
Other scientific studies show that some bacteria get tougher as they adapt. As Levy's report shows, although some antibacterial soaps contain an average of 2,500 micrograms of Triclosan, they still may not be enough to kill even the hardiest mutated bacteria.
In one study, researchers applied soap containing 150 micrograms of triclosan to a strain of wild (unmutated) E. coli -- bacteria commonly found in raw food. The results showed that it took a full two hours for the agent to kill 90 percent of the bacteria. It took two to four times as much triclosan under the same conditions to kill 90 percent of a mutated strain.
And adding antimicrobial chemicals to soap may be particularly ineffective. When researchers in the same study exposed the same strain of E. coli to just six micrograms of triclosan by itself, it killed as much of the bacteria in the same amount of time [source: Levy].
Overuse of antibiotics and antimicrobial cleaners may also be responsible for an increase of allergies. Read the next page to find out more.
A 2005 study found that more than half of the American population has an allergic reaction to at least one of 10 common allergens [source: AAAAI]. Some microbiologists suspect that the emergence of the antibacterial lifestyle may be responsible.
From birth, people are bombarded by unseen microbial life, which biologists call environmental flora. These little organisms are everywhere: in dirt, on countertops, in the air and even in your own body. While some cause infection, the majority are benign. Some are even helpful, like lactobacillus, which aids in our digestion of food and kills other, harmful bacteria.
Since there are a lot more flora than there are people, the human body has developed a way of warding off infection and allergies caused by microbial life. The human body's T-helper cells generate an immunoresponse to invasions by microbes. There are two types of T-helper cells: T-H1 cells help other cells form their own defenses against microbial invaders. T-H2 cells oversee the production of antibodies, which attack and kill foreign microbes that have entered the body.
Put together, these two types of helper cells are the reason you don't die whenever someone sneezes on you or you cut your finger. They are also the reason why you don't suffer constant allergic reactions whenever you breathe.
To work correctly, these helper cells must encounter microbes and allergens. The inoculations you get as a child are actually dead or weakened strains of microbes introduced into your system that your body uses to build its defenses against other, similar strains. In a household that relies heavily on antibacterial agents, a child's immune system may not get a chance to encounter enough allergens to produce the proper antibodies and defenses against them. The antimicrobial agents used in the home will have killed most of the allergens first.
While a parent can control his or her household, he or she can't sanitize the whole world. Once a child leaves an overly santized home, his or her underdeveloped immune system will be exposed to a host of microbes and allergens.
Even resisting personal overuse of antimicrobial chemicals may not prevent you from coming in contact with them. Antibiotics may be present in the food you eat and in the water you drink.
Modern agribusinesses use antibiotics to keep their livestock healthy. These antibiotics remain in the meat from those animals that makes it to the dinner table. And runoff from livestock yards and processing plants can make its way into groundwater and other sources from which people draw water.
Should antimicrobial agents be banned? That may be a bit premature. Read the next page to find out why the jury's still out.
Testing Antibacterial Soap
In July 2000, the Emerging Infectious Diseases Conference in Atlanta, featured several presentations concerning the relationship between the antibacterial lifestyle and the emergence of resistant bacteria. One of the presenters was Stuart B. Levy, who presented a paper entitled "Antibacterial Household Products: A Cause for Concern."
In his paper, Levy details studies which suggest that people may be at the threshold of a world where bacteria -- due to the use of antibacterial products and misused antibiotics -- may overtake people's ability to kill them.
Five years later, Levy was part of another study with five colleagues in his field where the findings were very different. The scientists divided 224 households into two categories: those that were given antibacterial products and those that were not. The study took place over the course of one year, and looked at families with similar backgrounds.
What the researchers found is that there was no significant difference in the amount of bacteria killed by the use of antibacterial soap over regular soap. They also found that there was no significant increase in the presence of resistant bacteria in the homes that used antibacterial products.
These findings were surprising. First, the study says that antibacterial soap is no better at killing germs than regular soap. It also says that the bacteria didn't mutate into super bacteria in the homes that used antibacterial soap. The study, entitled "Antibacterial Cleaning Products and Drug Resistance," contained one caveat: One year may not have been enough for the study to be conclusive [source: Aiello].
Sure enough, two years later, some of the same researchers from the 2005 study tried another study. Again, the researchers found that antibacterial soap showed no advantage over plain soap in its ability to kill bacteria. But they also collected data that suggested bacteria are indeed becoming increasingly cross-resistant as a result of antibacterial use.
Is it time to panic? The results are inconclusive. Although microbiologists can chart the mutation of some bacteria as a result of their exposure to antibacterial agents, this has only been done in a laboratory setting, and not in the real world. Still, scientists believe that bacterial mutation may be inevitable and continue their studies.
So what's the best way to fight germs? Sometimes the old ways are still the best ways. Read the next page to learn about the wonders of -- soap.
Antibacterial Soap vs Regular Soap
Sometimes plain old soap and other tried-and-true cleaning agents can work just as well as today's antibacterial products. Good, old-fashioned soap may not say "antibacterial" on its label, but it still kills germs. Sometimes it does a better job than antibacterial soap.
In addition, soap isn't the only thing that kills bacteria -- there are many naturally occurring antibacterial agents. Lemon juice, for example, changes the pH level in bacterial cells, creating an acidic environment in which microbes can't survive. Other naturally antibacterial substances dry cells out, killing the bacteria (bacteria most commonly thrive in moist environments). Still others, like bleach and certain alcohols completely obliterate the cells of the bacteria. Unlike the targeted attack of antimicrobial agents, bleach and certain alcohols simply cause the cells to lyse, or rupture.
Why haven't bacteria adapted to the agents found in bleach, alcohol and lemon juice? The reason why bacteria aren't resistant to these agents is because they do not leave a residue. There is no chance for surviving bacteria to adapt within the residual environment, so bacteria are just as susceptible to bleach and alcohol as they were 100 years ago. Skip the antimicrobial smart bomb and go for the big bleach blockbuster.
So what do we do to ward off superbacteria? Fortunately, the same rules to cleanliness still apply. The 2005 study showed that illness decreased among household members who washed their hands more, with or without antibacterial soap [source: Aiello]. Practicing good hygiene habits, like using alcohol-based hand sanitizer and staying away from people who have a cold, are still as valid as ever. And Stuart Levy assures us that if we take our antibiotics properly, the state of environmental flora will return to "what it was before the antibiotic/antibacterial onslaught" [source: Levy].
So stay well, stay warm and dry, and start rehearsing your ABCs while you wash your hands.
For more information on antibiotics and other related topics, visit the next page.
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More Great Links
- Aiello, Allison E., et al. "Antibacterial Cleaning Products and Drug Resistance." Emerging Infectious Diseases. October 2005. http://www.cdc.gov/ncidod/EID/vol11no10/pdfs/04-1276.pdf
- Andremont, A., et al. "Evaluating and Predicting the Ecologic Impact of Antibiotics." Clinical Microbiology and Infection. November, 2001. http://www.blackwell-synergy.com/action/showPdf?submitPDF= Full+Text+PDF+%2898+KB%29&doi=10.1046%2Fj.1469-0691.2001.00065.x &cookieSet=1
- Groch, Judith. "Antibacterial Soap No Better and May Be Worse Than Plain Soap." CMP Medica. August 16, 2007. http://www.consultantlive.com/medicalNews/showArticle.jhtml? articleID=201800663&cid=BreakingNews
- Levy, Stuart B. "Antibacterial Household Products: Cause for Concern." Emerging Infectious Diseases Conference. June 2001. http://www.cdc.gov/ncidod/eid/vol7no3_supp/levy.htm
- "MRSA Infection." Mayo Clinic. http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=3