HARMFUL bacteria, including "superbugs" that are resistant to antibiotics, might spread around hospitals on common fabrics used for clothes, curtains and other hospital items. Scientists in Ohio have found that some deadly bacteria can live on these materials for longer than three months.
All round the world there is an urgent need to stamp out the spread of infections in hospitals. In Britain last week, the National Audit Office published a damning report, saying that there are at least 100 000 such infections each year in Britain, costing the National Health Service as much as £1 billion annually.
In the US, the situation is just as serious. The Centers for Disease Control in Atlanta estimates that each year, 2 million people become infected in hospital. "Of these, around 80 000 die," says a CDC spokesman.
Most hospital infections are thought to be spread through sloppy hygiene, such as failure by doctors and nurses to wash their hands or to clean instruments properly. The possibility that fabrics are to blame has not been widely investigated before.
Alice Neely and Matthew Maley of the Shriners Hospital for Children in Cincinnati, Ohio, decided to look at how easily bacteria survive on five common hospital materials: pure cotton from clothing, cotton terry from towels, a cotton-polyester typically used for lab coats, pure polyester used in privacy curtains and polyethylene from splash aprons.
The researchers took 22 strains of bacteria and smeared them onto samples of the fabrics. These strains included common "superbugs" resistant to almost all antibiotics, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci.
It turned out that the staphylococci lived longest on polyester, surviving for up to seven weeks, and on polyethylene, lasting anything from three weeks to three months. The same was true of enterococci, which generally survived even longer than the staphylococcal strains. "Most bacteria tested in this study survived longer on polyester than on cotton," says the team. They say bacteria could spread when staff and patients handle polyester privacy curtains. "Staphylococci and enterococci survived for days to months on this fabric, suggesting such drapes could act as reservoirs for these bacteria."
Experts stress, however, that poor hand hygiene and failure to wash instruments properly probably dwarf any transmission via fabrics. Peter Hoffman of the Public Health Laboratory Service in London adds that cotton is the most common fabric in British hospitals, and items are regularly heat-disinfected before use. Where polyethylene is used-in splash aprons, for example-it is disposed of after treating a patient, like gloves. "It's accepted that the most important routes are dirty hands and instruments," says Hoffman.
Robert Weinstein of Rush Medical College in Chicago agrees that poor hand washing is the biggest problem, but thinks the new study is interesting. "It should give a better understanding of the dynamics of colony persistence on cloth," he says. It's not surprising that vancomycin-resistant enterococci survive for so long, he adds. "They are the cockroaches of the microbial world."
Author: Andy Coghlan
Source: Journal of Clinical Microbiology (vol 38, p 724)
New Scientist issue 26th February 2000
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