WASHINGTON (Reuters) - The mutated, drug-resistant "superbugs" that cause an increasing number of hospital infections and deaths can live for weeks on bed linens, computer keyboard covers and under acrylic fingernails, U.S. researchers reported on Monday.
The study supports other research that shows super-strict hygiene is needed to battle the bacteria, some of which are now nearly impossible to kill even with the strongest antibiotics.
A team at sanitation-services company Ecolab Inc. dabbed methicillin-resistant Staphylococcus aureus onto samples of bed linen, keyboard covers and acrylic fingernails.
MRSA could be detected eight weeks later on acrylic fingernails, six weeks later on computer keyboard covers and five days later on bed linens, the researchers told a meeting in Atlanta of the American Society for Microbiology.
"The results of this study clearly demonstrate the need for frequent hand washing and environmental disinfection in health care settings," said researcher Kris Owens of Mendota Heights, Minnesota-based Ecolab.
Staphylococcus aureus is usually harmless and very common, found on skin or in the noses of about 30 percent of people. It can cause stubborn problems such as rashes and boils and an infection is often mistaken for a spider bite.
In hospitals, MRSA can cause serious and sometimes deadly infections, including necrotizing fasciitis or "flesh-eating" disease. It resists almost everything but an intravenous antibiotic called vancomycin.
A study at Northwestern Memorial Hospital in Chicago, published in April, found that computer keyboards can contaminate the fingers, bare or gloved, of a nurse or doctor, who could then transfer bacteria to patients.
have shown that, despite the importance of
hand-washing, doctors, nurses and other health care workers
often fail to do so or do not wash thoroughly.
A quarter of serious cases of MRSA in hospitals are found in patients who have just arrived, researchers have said.
Rates of the MRSA superbug have soared in the last decade, with hospital cleanliness largely blamed for helping infection to spread.
Now research has found that in many cases patients are bringing the bug into hospital with them which creates the potential for it to spread further, according to a study in the British Medical Journal.
The research looked at cases of methicillinresistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococcus aureus (MSSA) bacteraemia in patients arriving at two Oxfordshire hospitals between 1997 and 2003.
These were the John Radcliffe, Radcliffe Infirmary and Churchill Hospitals, which operate together as one teaching hospital, and the Horton Hospital in nearby Banbury.
MRSA can infect many parts of the body but a serious form is when bloodstream infection occurs - bacteraemia.
The researchers, from the University of Oxford, found in the teaching hospitals that patients admitted from the community accounted for 49% of total MSSA cases and about 25% of MRSA bacteraemia cases.
The team found that the proportion of resistance to the antibiotic methicillin among patients admitted with Staphylococcus aureus bacteraemia increased from 14% in 1997 and 1998 to 26% in 2003.
At least 91% of patients who were admitted with MRSA bacteraemia had previously been in hospital, and half had never had MRSA detected before. They found that 70% were admitted to emergency medical and surgical services. Similar results were seen in the district hospital.
The researchers said: "We found that patients with MRSA bacteraemia tended to be older and were more likely to have been admitted to hospital previously."
After a healthcare worker died in September, it emerged that a form of Panton-Valentine Leukocidin (PVL) MRSA had also claimed a patient's life.
The strain attacks white blood cells and sufferers cannot fight infection.
Nine others also contracted the strain in the outbreak at University Hospital of North Staffordshire, Stoke-on-Trent.
Of these, only one was a patient.
This outbreak is the first time transmission and deaths due to
strain are known to have occurred in a healthcare setting in England
Health Protection Agency
In a statement the hospital said: "With the exception of one infection it is not clear at this stage whether transmission has occurred within the hospital or, as is more common, in the community which it serves.
"The hospital is continuing to take advice from the Health Protection Agency on management of the outbreak."
Hospital-associated strains of MRSA normally affect more elderly hospitalised patients.
But the PVL strain is unusual because it can affect young and otherwise healthy people.
In the outbreak in Staffordshire, the first person - Case A - who died was a healthcare worker who developed MRSA, and was being treated as a patient at the hospital.
The second fatality was a patient being who was being treated on the ward where Case A had worked.
The HPA said there have been other cases of this particular strain of PVL MRSA in England and Wales - but these have been in the community, not hospitals.
Thirteen cases were recorded in the community in 2005. All were skin and soft-tissue infections.
There have also been five deaths linked to PVL MRSA in the UK over the last two years - but these were other strains of the bug.
Marine Richard Campbell-Smith, 18, cut a leg in training and died after becoming infected with a form of PVL in 2004.
A 28-year-old woman also died from a form of the infection after picking up the bug in her local gym.
In a statement, the HPA said: "PVL-producing strains of MRSA have been seen in the UK before - however, the small numbers of cases reported have usually been in the community rather than a hospital setting.
"This outbreak is the first time transmission and deaths due to this strain are known to have occurred in a healthcare setting in England and Wales."
The agency identified those affected as being "among individuals in a hospital and their close household contacts in the West Midlands".
The agency only covers England and Wales.
Dr Angela Kearns, an MRSA expert with the HPA, said: "When people contract PVL-producing strains of MRSA, they usually experience a skin infection such as a boil or abscess.
"Most infections can be treated successfully with everyday antibiotics but occasionally a more severe infection may occur.
"The HPA is advising the hospital on outbreak control measures, and will continue to monitor MRSA infection nationally."
The PVL toxin is carried by less than 2% of the bacteria responsible for MRSA.
Although, it normally causes pus-producing skin infections, such as abscesses or boils, it can trigger more severe invasive infections such as septic arthritis, blood poisoning or a form of pneumonia.
Shadow health secretary, Andrew Lansley, said: "Over the last nine years there have been far too many cases where the government has allowed MRSA to become endemic.
"The inevitable result has been an evolving process leading to increased resistance to antibiotics.
"It is time for us to take on the threat of new and more dangerous bacteria."