The newly-found corbomycin and the lesser-known complestatin have a never-before-seen way to kill bacteria, which

is achieved by blocking the function of the bacterial cell wall. The discovery comes from a family of antibiotics called 

glycopeptides that are produced by soil bacteria.

The researchers also demonstrated in mice that these new antibiotics can block infections caused by the drug resistant 

Staphylococcus aureus which is a group of bacteria that can cause many serious infections.

  The findings were published in Nature today."Bacteria have a wall around the outside of their cells that gives them 

shape and is a source of strength," said study first author Beth Culp, a PhD candidate in biochemistry and biomedical

sciences at McMaster."Antibiotics like penicillin kill bacteria by preventing building of the wall, but the antibiotics that we found actually

 work by doing the opposite -- they prevent the wall from being broken down. This is critical for cell to divide.

"In order for a cell to grow, it has to divide and expand. If you completely block the breakdown of the wall, it is like it

is trapped in a prison, and can't expand or grow."

Looking at the family tree of known members of the glycopeptides, researchers studied the genes of those lacking 

known resistance mechanisms, with the idea they might be an antibiotic demonstrating a different way to attack 

bacteria.

"We hypothesized that if the genes that made these antibiotics were different, maybe the way they killed the bacteria 

was also different," said Culp.

Culp said: "This approach can be applied to other antibiotics and help us discover new ones with different mechanisms 

of action. We found one completely new antibiotic in this study, but since then, we've found a few others in the same family that have this same new mechanism."