A New Discovery About a Wonder Drug

By Jane Farrell

Researchers have discovered a new way in which the wonder drug penicillin fights infections.

Penicillin, discovered in 1928, works by attacking enzymes that build the bacterial wall cell. Once the medicine gets through that wall, the bacteria die.

Over the years, though, resistance to antibiotics has developed and is now a serious health threat. But with the latest discovery, it’s possible that penicillin can be used to thwart resistance in another way.

The new discovery, from investigators at Harvard Medical School: Penicillin and its variants do more than simply block cell-wall assembly. The researchers found that the medicines also set in motion a toxic malfunctioning of the wall-building machinery, which dooms the cell to a futile cycle of building and then immediately destroys it.

“It seems to be a common theme with some of the best antibiotics that we have: They don’t just inhibit the enzyme they are targeting; they actually convert that target so that whatever activity it has left becomes toxic,” said Thomas Bernhardt, associate professor of microbiology and immunobiology at Harvard Medical School.  “I think it’s important in understanding how the drug works, but it also teaches us fundamentally about how bacteria build a wall so we can find new ways we might throw a wrench in that process.”

Their findings were published in the journal Cell.