Antibacterial Soaps Encourage MRSA Bacteria to Colonize Your Nose

Although Olympic athletes may seem invincible, even a prime example of Olympian fitness like swimmer Ian "the Thorpedo" Thorpe is at the mercy of tiny microbes. After undergoing shoulder surgery, Thorpe reportedly contracted an infection of potentially deadly methicillin-resistant Staphylococcus aureus (MRSA) that will keep him from swimming competitively in the future. 

MRSA is an antibiotic-resistant strain of Staphylococcus aureus (S. aureus), a bacteria that can cause skin and soft tissue infections. Untreated, MRSA could lead to severe infection, coma, and even death.

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What makes Thorpe’s MRSA infection more frightening is that he contracted it at a hospital. These bacteria can prove resilient even in places that should be safe havens from serious infections. S. aureus infections are so wily that even seemingly hygienic habits like using antibacterial hand sanitizer may not protect you. In a recent study, researchers reported that certain antibacterial products containing the antimicrobial chemical triclosan may actually increase the risk of S. aureus—or staph—infection.

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How Common Are Hospital-Acquired Infections?

While hospitals are places you go to get treated for disease, consider that many different bacteria and viruses pass through hospitals each day on the skin and in the bodies of other patients. 

One in 25 hospital patients have at least one healthcare-associated infection (HAI), and in 2011, more than 700,000 people fell prey to HAIs, according to the Centers for Disease Control and Prevention.

Three in 10 Americans naturally carry staph bacteria in their noses, where the organisms lie dormant unless they have the chance to enter the blood stream through an opening—a surgical wound, for example. Up to 85 percent of staph infections are caused by a patient's own bacteria.

Can Your Antibacterial Soap Put You at Risk?

The safety of different antimicrobial chemicals in soaps and toothpastes has a long and convoluted history, particularly regarding the chemicals triclocarban and triclosan. 

The problem with these antimicrobials is that in doing their job—killing microbes—they may disrupt certain systems in the human body such as the endocrine—or hormone—system, potentially causing development problems. It’s possible that these antimicrobials are also contributing to the spread of antibiotic-resistant strains of bacteria by killing off their competition.

In a study published earlier this week in mBioresearchers from the University of Michigan found triclosan in human nasal secretions (snot), which could put people at an increased risk of S. aureus infection. The researchers found that rats exposed to triclosan are more susceptible to S. aureus nasal colonization than those who were not exposed.

Researchers weren’t surprised to find triclosan in human nasal secretions because other studies had already found the chemical in human urine, blood plasma, and breast milk. “However what was surprising was our data suggesting triclosan may be influencing the microbes that live in the nose, specifically S. aureus,” said study co-author Blaise Boles, Ph.D., an assistant professor at the University of Michigan.

Boles and his team found that triclosan can promote the binding of S. aureus to host proteins found in the nose—such as collagen, fibronectin, and keratin—essentially offering a home for the infection.

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“Nasal colonization with S. aureus is important because those [who are] nasal colonized are at increased risk for infection,” Boles said.

These findings, combined with past research, suggest that use of triclosan in consumer products should be re-evaluated, Boles said. “I personally avoid using products that contain triclosan, such as hand soaps, as there is no evidence they do a better job than regular soap and water,” he said. “Some hygiene products may contain compounds that have unintended consequences.”