Ionising machines may help to reduce the risk that patients will pick up an infection while they are being treated in hospital.

Researchers from Leeds University found the use of ionisers had a significant impact in cutting the number of infections caused by a potentially dangerous bacterium called acinetobacter.

We believe that the negative air ions are removing the bacteria from the air, so stopping the transmission of infection Dr Clive Beggs

The bug has been responsible for increasing numbers of sometimes fatal infections amongst hospital patients.

Ionisers were placed in the intensive care unit at St James's University Hospital, which has had recurrent problems with acinetobacter infections.

For the first six months the researchers, from the aerobiological research group in the University's school of civil engineering, monitored the normal situation in the unit.

They took samples from surfaces, patients and from the air to monitor bacteria levels, and logged the number of patient infections.

During the second half of the year-long trial, the ionisers were switched on, and the results were impressive - infections due to acinetobacter reduced dramatically.

Removing bacteria

Lead researcher Dr Clive Beggs said: "This is the first epidemiological study of its kind into the use of ionisers in hospital wards and the initial results are very promising.

"We believe that the negative air ions are removing the bacteria from the air, so stopping the transmission of infection.

"Our tests have focused solely on acinetobacter, but it's possible the ionisers may have had an effect on other airborne bacteria.

"We now need to carry out further research to determine exactly how the ions work and how widespread their effects could be."

Even without further research, the fact the ionisers are already making a difference is good enough for lead consultant at St James's intensive care unit, Dr Stephen Dean.

He said: "We wanted to be involved in the trial as infections are a major issue for units such as ours, where many patients are already very vulnerable.

"The results have been fantastic - so much so that we asked the University to leave the ionisers with us.

"Since the trial finished in May, we've kept them in operation, and have continued to see greatly reduced acinetobacter infections on the ward."

Difficult to treat

Dr Kevin Kerr, lead clinical microbiologist on the project, said: "Acinetobacter infections are very difficult to treat as the bacterium is resistant to nearly all antibiotics, so prevention of these infections is of key importance.

"Ionisers may become a powerful weapon in the fight against hospital-acquired infection."

The researchers have compiled their report for NHS Estates who funded the study, and will be publishing a paper on the research in the new year.

Acinetobacter is found naturally in the environment.

It can survive drying, and can persist in dust and on inanimate surfaces for extended periods.

While it poses no real threat to healthy humans, when the body's defences are weakened it can cause serious infections.

It has become a particular problem in intensive care units where patients are already critically ill.

Acinetobacter can cause infections of the lung (pneumonia), blood stream (septicaemia) and infections of surgical wounds and burns as well as urine infections.

Such infections are difficult to treat as many strains of the bacterium are resistant to more than one antibiotic, with the most resistant strains only treatable by one or two drugs.

Fully resistant strains are expected to develop in the near future.

Ionisers work by producing small negatively charged ions of oxygen, which are thought to be good for health.