Scientists identify new resistance genes in superbugs resistant to a common disinfectant (Update)

November 28, 2013
Credit: Flickr/Backdoor Survival

Researchers have identified a resistance protein that allows bacteria to survive chlorhexidine, a disinfectant commonly used in wipes, cleansers and mouthwashes in hospitals.

A study led jointly by the University of Leeds and Macquarie University in Australia showed how the superbug Acinetobacter baumannii—prevalent among soldiers treated in medical facilities in Iraq and Afghanistan—can pump the disinfectant out of its system.

The findings are critical for the design of new chemicals to combat the germ.

Professor Peter Henderson of the University of Leeds' School of Biomedical Sciences said: "The Australians saw that, in response to chlorhexidine, a gene becomes active and produces a protein they called Acinetobacter Chlorhexidine Efflux, or 'Ace' for short. Working together, we demonstrated that Ace binds to the disinfectant and effectively pumps the chlorhexidine that has leaked through the cell wall out again."

Acinetobacter baumannii was once treatable with normal antibiotics but is now one of the most worrying superbugs threatening the medical system. It has been particularly associated with infections of military personnel injured in Iraq and Afghanistan. Its ability to survive on disinfected artificial surfaces for long periods has allowed it to thrive and spread through the military and into the civilian medical system.

Sally Davies, the Chief Medical Officer for England, said in March that antibiotic resistance posed a "catastrophic threat" that could mean that even minor surgeries might carry deadly risks by the 2030s.

Professor Henderson said: "Identifying the resistance protein now allows us to look for a compound that will inhibit the protein's activity and form the basis of a new treatment against infection."

The early indications are that the protein specifically binds with chlorhexidine rather than other antibiotic molecules. Although some multi-drug resistant proteins have been found, the fight against superbugs has generally been characterised by a painstaking search for several proteins associated with resistance to particular drugs and chemicals.

Members of the University of Leeds' Astbury Centre for Structural Molecular Biology are at the forefront of work on "pump" proteins.

Professor Henderson said: "There are very similar genes in other pathogenic organisms. Our next step will be to explore what these proteins do in those other organisms. In some cases, it is strongly suggested that they make the germ resistant to chlorhexidine, but in others it appears to be something else. We need to find out what that is."

He added: "The bad news is that the bugs are winning. We can't devise new antibiotics nearly fast enough to find a new way of dealing with them and there is not enough funding to pursue the research. This project is typical of the sort of work that we have to do to win the fight against superbugs."

Professor Ian Paulsen at Macquarie University said: "Antiseptics and disinfectants are a key defence used to control the spread of these bacteria in hospitals particularly. Following this discovery, we plan to investigate ways to block this pump. Such work is important in ensuring that we can continue to use successfully this disinfectant to reduce rates of infection in hospitals."

The research is published in the journal Proceedings of the National Academy of Sciences.

Explore further: Study finds weakness in armor of killer hospital bacteria

More information: The research has been published in the journal Proceedings of the National Academy of Sciences this week.

Related Stories

Rapid detection of superbugs

November 18, 2013

A new lab test that detects antibiotic resistance genes quickly could help doctors choose the right drugs to knock out superbugs.

Promising new approach to drug-resistant infections

October 15, 2013

A new type of antibiotic called a PPMO, which works by blocking genes essential for bacterial reproduction, successfully killed a multidrug-resistant germ common to health care settings, UT Southwestern Medical Center researchers ...

Recommended for you

Zika virus infection alters human and viral RNA

October 20, 2016

Researchers at University of California San Diego School of Medicine have discovered that Zika virus infection leads to modifications of both viral and human genetic material. These modifications—chemical tags known as ...

Food-poisoning bacteria may be behind Crohn's disease

October 19, 2016

People who retain a particular bacterium in their gut after a bout of food poisoning may be at an increased risk of developing Crohn's disease later in life, according to a new study led by researchers at McMaster University.

Neurodevelopmental model of Zika may provide rapid answers

October 19, 2016

A newly published study from researchers working in collaboration with the Regenerative Bioscience Center at the University of Georgia demonstrates fetal death and brain damage in early chick embryos similar to microcephaly—a ...

Scientists uncover new facets of Zika-related birth defects

October 17, 2016

In a study that could one day help eliminate the tragic birth defects caused by Zika virus, scientists from the Florida campus of The Scripps Research Institute (TSRI) have elucidated how the virus attacks the brains of newborns, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.