Washington, July 14 (IANS): It may be possible to rein in the spread of antibiotic-resistant superbugs without the need to develop new antibiotics as it has been found that these bacteria possess the natural ability to become vulnerable to existing antibiotics.

A study found that to kill their competitors, these bacteria need to relinquish their ability to defy antibiotics.

"If we can identify ways to force the entire population of drug-resistant bacteria to undergo this change, we stand a better chance of fighting the growing problem of antibiotic resistance," said first author Brent Weber from Washington University School of Medicine in St. Louis.

"Instead of looking for new antibiotics, we could restore bacteria's vulnerability to antibiotics we already have," Weber said in a study that appeared online in the journal PNAS.

The researchers studied samples of A. baumannii isolated from a 2012 outbreak at a Canadian hospital. Four patients were infected, and one died.

The researchers expected the bacteria to readily kill other bacteria by producing and injecting a poison into their bacterial competitors. Killing the competitors should help A. baumannii infections spread widely and quickly.

But instead, the scientists found that the bacteria's poison injection system was disabled in most of the samples from the Canadian outbreak. They identified chunks of bacterial DNA that were shutting down the system.

These pieces of DNA, known as plasmids, also carried genes that enabled the bacteria to resist antibiotics.

In addition, the scientists found that part of the bacterial population regularly deactivated the plasmids, which turned on the poison injection system and transformed the bacteria into killers.

But doing so meant the bacteria also turned off the antibiotic-resistance genes, making the bacteria vulnerable to antibiotics.

"This knowledge could lead to more effective treatments and better strategies for preventing the development of superbugs," Feldman said.