The key to killing methicillin-resistant Staphylococcus aureus -- also known as MRSA or golden staph -- may not be new-fangled treatments after all, but a treatment for an infected eyelash follicle found in a 1,000-year-old book.
The MRSA "superbug" is notoriously difficult to treat. Over the years, it developed resistance to beta-lactam antibiotics, which include common treatments like penicillin and its derivatives, cephalosporins, monobactams and carbapenems. It's also a particular problem in hospitals and nursing homes, where a high percentage of the population of which have open wounds and weakened immune systems.
Although new remedies, consisting of other drugs and antibiotics, are found and used, it is never long before newer strains of the bacteria emerge with new resistances to the treatments.
So the recipe -- taken from "Bald's Leechbook," one of the oldest known examples of a medical textbook --astonished researchers at the University of Nottingham when it killed up to 90 percent of MRSA bacteria in a laboratory setting.
The team decided to test the recipe -- consisting of garlic, leek, wine and bovine bile salts -- after microbiologist Dr Freya Harrison got talking with Anglo Saxon scholar Dr Christina Lee about the recipe. It reads as follows:
"Work and eye salve for a wen, take cropleek and garlic, of both equal quantities, pound them well together, take wine and bullocks gall, of both equal quantities, mix with a leek, put this then into a brazen vessel, let it stand nine days in the brass vessel, wring out through a cloth and clear it well, put it into a horn, and about night time apply with a feather to the eye; the best leechdom."
The team used leeks and garlic, hoping that they were similar enough to the leeks and garlic that were around 1,000 years ago, some organic vintage wine from a historic English vineyard, and bovine bile salts usually used to treat humans who have had their gall bladders removed. Instead of a brass vessel, which would have been difficult to sterilise, they used glass bottles, including squares of brass in with the mixture -- copper is known to kill bacteria.
By the end of the nine days, Dr Harrison discovered that the bacteria that had been on the leeks and garlic had been killed by the brew.
"It was self-sterilising," she told New Scientist. "That was the first inkling that this crazy idea just might have some use."
It was then tested on pieces of skin taken from mice infected with MRSA -- and killed about 90 percent of the bacteria, the same proportion killed by Vancomycin, which is usually used to treat golden staph.
"We thought that Bald's eye salve might show a small amount of antibiotic activity, because each of the ingredients has been shown by other researchers to have some effect on bacteria in the lab -- copper and bile salts can kill bacteria, and the garlic family of plants make chemicals that interfere with the bacteria's ability to damage infected tissues. But we were absolutely blown away by just how effective the combination of ingredients was," Dr Harrison said.
"We tested it in difficult conditions too -- we let our artificial 'infections' grow into dense, mature populations called biofilms, where the individual cells bunch together and make a sticky coating that makes it hard for antibiotics to reach them. But unlike many modern antibiotics, Bald's eye salve has the power to breach these defences."
From a historical perspective, the recipe -- and others in the volume -- may provide some clues about the methods used to determine medical treatments in the middle ages, as well as new remedies that can be adapted today.
"Medieval leech books and herbaria [collections of preserved plant specimens] contain many remedies designed to treat what are clearly bacterial infections," Dr Lee said.
"Given that these remedies were developed well before the modern understanding of germ theory, this poses two questions: How systematic was the development of these remedies? And how effective were these remedies against the likely causative species of bacteria? Answering these questions will greatly improve our understanding of medieval scholarship and medical empiricism, and may reveal new ways of treating serious bacterial infections that continue to cause illness and death."
Dr Harrison will be presenting the research at the Society for General Microbiology conference this week in Birmingham, the UK.