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A Medieval Remedy for Modern Day ‘Superbugs’?
A thousand-year-old Anglo-Saxon remedy for eye infections that originates from a manuscript in the British Library has been found to kill methicillin-resistant Staphylococcus aureus (MRSA) in an unusual research collaboration at the University of Nottingham.
Dr. Christina Lee, an Anglo-Saxon expert at the School of English, has enlisted the help of microbiologists at the University’s Center for Biomolecular Sciences to recreate a 10th-century potion for eye infections from Bald’s Leechbook, an Old English leather-bound volume in the British Library, to see whether it really works as an antibacterial remedy. The Leechbook is one of the earliest known medical textbooks and contains Anglo-Saxon medical advice and recipes for medicines, salves, and treatments.
Early results with the “potion,” tested in vitro at Nottingham and backed up by tests in mice at Texas Tech University in the U.S., are, in the words of the U.S. collaborator, “astonishing.” The solution has had remarkable effects on MRSA, one of the most antibiotic-resistant “bugs,” costing modern health services billions of dollars each year.
The team now has data showing that Bald’s eye salve kills up to 90% of MRSA bacteria in in vivo wound biopsies from mice. They believe that the bactericidal effect of the recipe is not due to a single ingredient but to the combination used and to the brewing methods and container material. Further research is planned to investigate how and why this works.
The ancient recipe calls for two species of allium (garlic and onion or leek), wine, and oxgall (bile from a cow’s stomach). It describes a specific method of making the topical solution, including the use of a brass vessel to brew it in, straining to purify it, and an instruction to leave the mixture for 9 days before use.
The scientists at Nottingham made four separate batches of the remedy using fresh ingredients each time, as well as a control treatment using the same quantity of distilled water and a brass sheet to mimic the brewing container but without the vegetable compounds.
The remedy was tested on cultures of S. aureus in both synthetic wounds and in infected wounds in mice.
The team made artificial wound infections by growing bacteria in plugs of collagen and then exposing the plugs to each of the individual ingredients or the full recipe. None of the individual ingredients alone had any measurable effect, but when combined according to the recipe, the S. aureus populations were almost totally obliterated: about one bacterial cell in a thousand survived.
The team then went on to see what happened if they diluted the eye salve, as it is difficult to know how much of the medication bacteria would be exposed to when applied to an actual infection. They found that when the medication was too dilute to kill S. aureus, it interfered with bacterial cell-to-cell communication (quorum sensing). This is a key finding, because bacteria must “talk” to each other to switch on the genes that allow them to damage infected tissues. Many microbiologists think that blocking this behavior could be an alternative way of treating infections.
Lee said: “Medieval leech books and herbaria contain many remedies designed to treat what are clearly bacterial infections (weeping wounds and sores, eye and throat infections, skin conditions, such as erysipelas, leprosy, and chest infections). 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. Kendra Rumbaugh conducted in vivo testing of Bald’s remedy on MRSA-infected skin wounds in mice at Texas Tech University. Rumbaugh said: “We know that MRSA-infected wounds are exceptionally difficult to treat in people and in mouse models. We have not tested a single antibiotic or experimental therapeutic that is completely effective; however, this ‘ancient remedy’ performed as good if not better than the conventional antibiotics we used.”
Source: University of Nottingham; March 30, 2015.