2 university researchers fighting back against antibiotic resistance

The 1928 discovery of penicillin has been widely touted as one of the greatest scientific achievements in the past century. This first antibiotic went into more frequent use after World War II, but bacteria quickly found a natural way to ward it off; within two to three years of its introduction into health clinics, scientists isolated the first penicillin-resistant bacteria.

Today, pathogens like MRSA (methicillin-resistant Staphylococcus aureus) cause thousands of deaths each year in this country. With experts recognizing that the overuse of all antibiotics is creating a major public health problem, researchers in the lab of Erik Sontheimer at Northwestern University’s Weinberg College of Arts and Sciences have taken a step toward outmaneuvering resistant bacteria.

Sontheimer (pictured on the right in the photo) and post-doctoral fellow Luciano Marraffini (left) became involved in the problem by trying to answer questions about horizontal gene transfer, which is how bacteria can spread antibiotic resistance. In conjugation—one form of horizontal gene transfer—bacteria mate and pass on resistance genes from one cell to the other. This can happen between bacteria that are harmless to humans and those that can be dangerous. Sometimes foreign genes benefit the recipient bacterium, but in other cases (such as when the foreign genes come from viruses) they do not. Therefore many bacteria have evolved mechanisms to limit or control their exposure to horizontal gene transfer. Marraffini and Sontheimer’s findings, which were published in the December 2008 issue of Science, offer insights into a new mechanism used by bacteria to stop horizontal gene transfer.

If their work eventually leads to successful clinical application, patients in hospitals may someday be able avoid infections like MRSA altogether. It could also lead to fighting antibiotic resistance in other harmful bacteria, including those that cause salmonella, tuberculosis, and cholera. “If this could be exploited like RNA interference, it would be a very, very big thing,” Sontheimer says.

Click here to read the full story by Laura Schocker and see more photos.