Selfish bacteria that can be used to treat infection found

The selfish behaviour of the bugs can be exploited to treat antibiotic-resistant infections.

London: British scientists have identified for the first time some selfish bacteria that act in their own interest and don`t help their infection-causing mates, a finding that could lead to new treatment for infections.

Researchers at the University of Nottingham who discovered these uncooperative bacteria said the selfish behaviour of the bugs can be exploited to treat antibiotic-resistant infections.

Scientists believe that bacteria work together by using a well-studied communication system called Quorum Sensing (QS), through which they coordinate among themselves for releasing toxins during infection.

But, this is the first time the scientists have found a unique behaviour in bacterial cells that can actually reduce the severity of infection.

In Staphylococcus aureus infections, the researchers found that bacteria defective in QS can benefit from "opting out" of toxin production.

By doing so, they can invest more energy in reproducing -- whilst taking advantage of the nutrient-rich infection that is maintained by their neighbours.

By looking after themselves in this way, QS-deficient bacteria are quickly able to outnumber other bacteria that are busy producing toxins. As a result the overall severity of infection is reduced as fewer toxins are produced.

"This opens up the interesting possibility of using these uncooperative bacteria to treat infection," said study author Dr Eric Pollitt who presented their findings at the Society
for General Microbiology`s autumn meeting in Nottingham.

"It`s an interesting concept of `fighting like with like`."

For their study, Dr Pollitt and his team introduced S aureus bacteria into waxworms that subsequently developed infections.

They found that the QS-deficient bacteria could not only outgrow normal bacteria in the same population, they also invaded other cooperating populations to reduce the severity
of infection.

"This means that we could potentially isolate QS-deficient bacteria and use them to treat clinical S. aureus infections," said Dr Pollitt.

Scientists have been looking for new approaches to treat S aureus infections as many strains of the bacterium, such as Meticillin-resistant Staphylococcus aureus (MRSA), are
resistant to antibiotics.

"Importantly, as any treatment involving QS-deficient bacteria would not be based on antibiotics, it could complement current treatments for S aureus infections," said Dr Pollitt.

"This work also highlights that the interactions between bacteria during an infection can be just as important as the interactions between the bacteria and the host."