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. The work was funded under a European International Research Staff Exchange Scheme (IRSES) project involving the University of Oslo, University of Leeds and Macquarie University. Researchers from Flinders University, Australia also contributed to the research.
Graham Askew, Simon Walker, BBSRC (Jan 2018), £699,781
Jennifer Tomlinson, Royal Society (Jan 2018), £512,801
Jennifer Tomlinson, Royal Society-Research Fellows Enhancement Award (Dec 2017), £94,681
Helen Miller, AB AGri Grant (Dec 2017), £73,600
Simon Walker, Royal Society Enhancement Award (Dec 2017), £10,000
Carrie Ferguson, Bryan Taylor, Harry Rossiter, The Physiological Society (Dec 2017), £7,392
Ralf Richter, Royal Society (Dec 2017), £6,000
Christine Foyer, British Council Newton Fund (Dec 2017), £49,840
Adrian Whitehouse and colleagues in School of Chemistry and University of Liverpool, MRC (Nov 2017), £622,319
Michelle Peckham, Neil Ransom, MRC (Nov 2017), £495,159
Dave Lewis, British Council India (Nov 2017), £22,540
Elton Zeqiraj, Royal Society (Nov 2017), £15,000
Hannah Dugdale, Royal Society (Nov 2017), £15,000
Shaunna Burke, Cancer Research UK Innovation Grant (Nov 2017), £20,000
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Jessica Kwok, Wings for Life (Nov 2017), £87,365
Tom Bennett, BBSRC (Oct 2017), £523,679
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Nikita Gamper, BBSRC (Oct 2017), £490,426
Amanda Bretman and colleagues from UEA, NERC (Oct 2017), £430,886
Juan Fontana, Rosetrees Trust consumables grant (Oct 2017), £22,500
Helen Miller, DSM Nutritional Products AG (Sep 2017), £69,988
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Jamie Johnston, Physiological Society (Sep 2017), £10,000
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Graham Askew in collaboration with Bangor University, BBSRC (Mar 2017), £477,383
Stephen Muench, BBSRC (Mar 2017), £132,945
Nic Stonehouse, MRC (Mar 2017), £906,341
Bill Kunin, Steve Sait, BBSRC (Mar 2017), £602,831
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Sheena Radford, Wellcome Trust (Mar 2017), £1,836,482
Beatrice Filippi, Royal Society (Mar 2017), £15,000
Tom Bennett, Royal Society (Mar 2017), £15,000
Jamie Johnston, Royal Society (Mar 2017), £15,000
Ryan Seipke, BBSRC (Feb 2017), £52,116
Mary O'Connell, BBSRC (Feb 2017), £46,986
Hannah Dugdale, NERC (Feb 2017), £504,138
Anastasia Zhuravleva, EPSRC (Jan 2017), £100,792