How Superbugs Fight Antibiotics: Scientists Uncover Origin of Resistance

First Posted: Aug 29, 2013 10:57 AM EDT

Antibiotics can be extremely useful when treating bacteria and illnesses. Yet over time, bacteria can become antibiotic-resistant, turning into "superbugs." Now, though, researchers have uncovered a novel mechanism that a particular superbug uses to fend off a key front-line antibiotic. The findings could reveal new ways to treat this type of superbug in patients.

Before antibiotics were used in patients, a cut or a strep throat could lead to serious illness or even death. Yet new medicines gave doctors a way to treat bacterial infections. Unfortunately, bacteria continue to evolve and develop novel ways to overcome antibiotics.

"Antibiotic resistance is one of the major public health threats of the 21st century," said Cesar Arias, one of the researchers, in a news release. "These superbugs can make antibiotics useless, which makes certain bacterial infections virtually untreatable."

In this particular study, the researchers focused on a superbug called vancomycin-resistant enterococci, or VRE. This superbug usually affects patients who have a compromised immune system or who are critically ill. This makes learning how to treat it extremely important for those who are in hospitals. In fact, the frequency of VRE in hospitalized patients has increased eightfold in just the last 15 years. This makes it the second most common hospital-associated bacterium in the United States.

In order to get a closer look at how VRE manages to ward off the antibiotic, daptomycin, the researchers used fluorescent labeled daptomycin and examined the interaction between the superbug and the antibiotic. More specifically, they used advanced microscopy techniques to get a closer look.

So what did they find? It turns out that the VRE cells divert the antibiotic and "trap" it to an area where it is rendered ineffective. This resistance is completed by changing the composition of the bacterial cell membrane.

"The importance of this work is that an understanding of 'how' bacteria become resistant can then lead to a search for new antibiotics that target the resistance pathway itself, thus overcoming and preventing resistance," said Barbara E. Murray, one of the researchers, in a news release.

The findings are crucial for better understanding these superbugs and fighting against them. As more bacteria evolve and become resistant to antibiotics, it's more important than ever to counter them through new methods.

The findings are published in the journal mBio.

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