Reporter 434, 29 March 1999
Over three million people lost their lives last year to a disease the world believed it had beaten. And tuberculosis is not the only killer making a comeback. Newly-immune to the best medical defences, many super-bugs are again on the attack. A former air-conditioning engineer may sound an unlikely saviour, but University researcher Clive Beggs is leading a multi-disciplinary team investigating a novel solution at Leeds General Infirmary
One in ten people treated in British hospitals pick up another infection during their stay. Some patients, such as the very young, the elderly and those with damaged immune systems are particularly vulnerable. Many of the bacteria and fungi causing these infections can be transmitted from ward to ward through the ventilation and air conditioning systems.
Civil engineering researcher Dr Beggs was at a conference when a chance conversation gave him the idea of applying his building services expertise to this growing problem. He believes installing ultra-violet (UV) lamps can kill the bugs and help stop them spreading airborne diseases in hospitals. Over the next eighteen months the research team will place the lamps at strategic places in and above wards at the LGI to study their effect on the hospital's unwanted visitors.
By studying the flow of air through the ventilation ducts and around the rooms the team will determine the best locations for the lamps, and how effective they are.
The NHS-sponsored project is being carried out jointly by the microbiology department and public health researchers in civil engineering, with support from UV lamp manufacturer Hanovia Ltd.
Dr Beggs believes the team's unique combination of skills offers a real step forward. "Very little is known about the characteristics of airborne microbial transmission within hospital buildings. There is considerable scope to apply engineering solutions to overcome the problem," he said. "For example, as air comes into contact with people in wards, it warms ups and establishes complex convection currents. These currents can carry air-borne bacteria around hospital buildings, with the result that infections are spread. We can model this transmission using computational fluid dynamics computer simulation."
Disinfection with ultra-violet radiation is widely used in the water and food industries, but was deemed unnecessary in hospitals due to the development of effective antibiotics. However, the increase of resistant bacteria has left hospitals with few other options.
These bacteria include a new, multiple-drug resistant strain of tuberculosis. The first case of this disease in Leeds was recently diagnosed and its victim has been asked not to leave his house by health officials. The City Council have even agreed to make up his salary to keep him away from other members of the public.
Tuberculosis is the biggest killer in the world. One in three of the global population is infected, mainly in sub-Saharan Africa, India and southeast Asia. The team hopes they will not find evidence of it in the LGI, but has more than half an eye on the global situation.
"It can take up to four weeks to diagnose tuberculosis, during which time the disease can spread rapidly and each untreated case in the community can result in up to four more. If we can show the UV lamps are effective at cutting the number of airborne pathogens then it has massive implications for hospitals throughout the world," said University clinical microbiologist Kevin Kerr.
A second University clinical microbiologist, Mark Wilcox, is involved in separate research aimed at reducing the number of cases of hospital-acquired infections, and suggests the use of antibiotics by hospitals needs to be addressed.
Dr Wilcox recently chaired a working party looking at diarrhoeal infections caused by the bacterium Clostridium difficile, spread primarily in hospitals. The use of antibiotics can leave patients susceptible to the bug, whose effects are estimated to cost an average-size district general hospital £400,000 per year.
Dr Kerr emphasised the ultra-violet research project will also benefit significant strategies aimed at preventing airborne infection in some of the most vulnerable groups of patients treated in hospital, such as bone marrow transplant recipients.
The LGI will be the first hospital in the UK to be fitted with ultra-violet lamps. With many medicines becoming increasingly ineffective, and long-forgotten illnesses again wreaking havoc, it is unlikely to be the last.
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