Scientists have discovered a new and highly effective weapon against deadly superbugs like the MRSA sweeping through Britain's dirty hospital wards – green French muck.
The dramatic antibiotic success of agricur, a clay made from ancient volcanic ash found near the Massif Central, marks it out as a potential rival to penicillin, the wonder drug of the 20th century. In experiments, the clay killed up to 99 per cent of superbug colonies within 24 hours. Control samples of MRSA (methicillin-resistant Staphylococcus aureus) grew 45-fold in the same period.
The clay has a similar effect on other deadly bacteria tested, including salmonella, E. coli, and a flesh-eating disease called buruli, a relative of leprosy which disfigures children across central and western Africa. It has been classed as "an emerging public health threat" by the World Health Organization (WHO).
MRSA is also a growing concern. Since the early 1990s, deaths in the UK have risen sharply from fewer than 100 annually to more than 1,600 in 2005. The Governmentrecently announced new measures to deep clean all hospital wards in an attempt to cut the number of infections.
Many other bacteria have also developed resistance to medicine's arsenal of antibiotics, largely because patients stop using prescribed drugs when they begin to feel better rather than finishing their course of treatment, allowing the hardiest bugs to survive and spread. Some bacteria are now resistant to a spectrum of drugs. As a result, the developed world is starting to see the return of diseases, such as tuberculosis, that had been all but wiped out a few decades ago.
Scientists have been searching for new antibiotics to replace penicillin, methicillin and their relatives but until now have had only limited success. Agricur's discovery could lead to a whole class of antibiotics to which bugs such as MRSA have no resistance, according to scientists.
Dr Lynda Williams and Dr Shelley Haydel of Arizona State University will present the results of their research on agricur and other clays to the Geological Society of America's annual meeting in Denver tomorrow.
"We have found several antibacterial clays," said Dr Williams, a mineralogist who is trying to work out the chemicals that make them special. "We have multiple working hypotheses. Our primary hypothesis is that the clay minerals transfer elements, not yet identified, to the bacteria that impede their metabolic function.
"It is entirely possible that it is not one single element that is toxic to the bacteria, but a combination of elements and chemical conditions that attack the bacteria from different angles so as to overwhelm their defence systems," she said.
Another possibility, less likely but potentially more significant, is that the clays work through a physical rather than a biochemical process. In that case, bacteria might never develop resistance.
Clay has long been used as a health treatment in spas, but that is because it holds heat longer than water, and draws toxins out of the skin. Clay is also sometimes eaten as a folk remedy for nausea. "It's fascinating," said Dr Haydel, a microbiologist. "Here we are bridging geology, microbiology, cell biology. A year ago, I'd look at the clay and say, 'Well, that's dirt.'"
The effectiveness of the French green clays, which are mostly made of minerals called smectite and illite, was first demonstrated by Line Brunet de Courssou, a French doctor fighting buruli at clinics in Ivory Coast and Guinea.
When she approached the WHO in 2002 with 50 case studies showing how the flesh-eating disease had been halted by her clay poultices, the organisation described her work as "impressive" but denied her funding because of a lack of scientific evidence. After de Courssou's death, her son, Thierry, went looking on the internet for scientists willing to test agricur and found Dr Williams, who has specialised in the study of clay.
The nurse's story: A new family torn apart by the effects of deadly bacteria
Maribel Espaba died just five days after giving birth to her first child in September last year after contracting MRSA.
A nurse since the age of 17, Mrs Espaba, 33, worked in the diabetic ward at the University Hospital of North Staffordshire, the same hospital where she contracted the disease.
She fell ill within days of returning home with her new son, Arwen, who had been born after Mrs Espaba underwent a Caesarean section. Despite being rushed back to hospital, she died from blood poisoning and pneumonia brought on by the MRSA strain called PVL.
Earlier in the year, a patient in her ward had fallen victim to the MRSA strain but the bug had not been spotted until Mrs Espaba's death.
Her husband, Wenn Espaba, said: "When the doctors told me she had died I was numb... They had not mentioned to my wife that there had been an outbreak of the bug, even though she worked at the hospital."
Following the death of Mrs Espaba and the other patient, screening of all patients, staff, family and friends revealed another 10 cases.
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