College of LAS « Illinois


Reversing Resistance


Scientists are winning some skirmishes in the battle against antibiotic resistance. Chemists from the College of Liberal Arts and Sciences recently completed successful proof-of-concept experiments of a drug that diminishes the ability of resistant genes to replicate.

Working with cell cultures of Escherichia coli bacterium, a research team led by Paul Hergenrother has designed and administered a drug that shuts down the bacteria's ability to replicate plasmids—tiny, circular pieces of DNA that bacteria routinely exchange.

Antibiotic resistance is often passed from one generation to the next when plasmids carrying resistance genes are copied during cell division. Hergenrother's drug, called apramycin, prevents these resistance-carrying plasmids from duplicating so that only a single copy is passed along to the daughter cells. In this way, the population of resistant bacteria is halved with each cell division. Eventually, the colony loses its ability to resist antibiotics and the bacteria become targets once again.

As encouraging as the results are, a challenge for Hergenrother's team is to make the process faster. Currently it takes more than a couple hundred generations before the bacteria are susceptible to antibiotics again. It can take several days for this many generations to grow in cell cultures. How long that takes in patients remains to be seen. But Hergenrother is studying ways to boost the compound's ability to bind to plasmids, speeding up the process.

Escherichia coli are common intestinal bacteria that are responsible for many foodborne illnesses. Most infections come from eating undercooked ground beef or drinking sewage-contaminated water. Hergenrother's team is examining other bacteria as well, concentrating on the "superbugs"—those bacteria resistant to many antibiotics.

By Holly Korab
Fall/Winter 2005-06