Move on, MRSA

November 29, 2012

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One bacterial strain is causing some very big problems in U.S. hospitals and for wounded soldiers abroad. It’s called MRSA, and it’s a problem because it has figured out how to defend itself against just about every antibiotic weapon that we have. Fortunately, an NC State chemist has developed a new chemical compound that may help stop this threat.

Christian Melander has spent the last half-decade working on a way to neutralize methicillin-resistant Staphylococcus aureus, or MRSA, one of the most common – and most difficult to treat – antibiotic-resistant bacterial strains.

“Like any bacteria, MRSA goes in, sets up shop in the body, and then essentially pollutes the environment around itself – that ‘pollution’ is what makes people sick,” Melander says. “In normal situations, antibiotics go in, disrupt the cell structure of the bacteria and destroy it. Then your body can clean up the mess. But when a bacterial strain becomes resistant to antibiotics, we have to continue upping the dosages or strength of the medications we use against it. Eventually, the treatment can become just as harmful as the bacteria itself.”

Christian Melander

In 2009, Melander developed a compound that, when used with regular antibiotics, “recharged” the antibiotics and made them effective again. In his latest project, he’s increased the compound’s strength so that the antibiotics work at normal dosage levels. If what he’s seen thus far in test tubes turns out to work as well in people, Melander’s compound will provide an effective weapon against MRSA, without the side effects associated with high dosages of super-strong antibiotics.

When antibiotics interact with resistant bacteria, receptors on the surface of the bacteria identify the antibiotic as a threat. The bacteria can then choose what to do to survive. MRSA has two main ways to defend itself against antibiotics. It can shield itself by creating a biofilm – a thin layer that prevents the antibiotic from entering its cell – or it can change its own genetic makeup, so the antibiotic can’t get in and mess with the bacteria’s cell structure.

Melander’s compound, instead of trying to directly combat MRSA’s defense mechanisms, works by disarming them before they can be activated. It interferes with the bacteria’s ability to recognize the antibiotic, so it can’t initiate a defensive response.

“What we’ve done is create a compound that blinds MRSA to the fact that an antibiotic is present,” Melander says. “So the bacteria don’t mount a defense and the antibiotic goes in and destroys them. When you’re dealing with bacteria, it’s always an arms race. Hopefully this compound will help us gain the upper hand.”