Dry run to beat superbugs

Researchers are investigating the effects of humidity on hospital ‘superbugs’ using one of the largest biological test chambers in the world.


Researchers at Bradford University are investigating the effects of humidity on hospital ‘superbugs’ using one of the largest biological test chambers in the world.

The Bradford Infection Group (BIG), based at Bradford’s Schools of Engineering, Design and Technology and Life Sciences, has received a £175,000-plus grant to investigate alternative methods for controlling hospital-acquired infections caused by bacteria such as acinetobacter.

Using the grant, awarded by the Department of Health’s National Institute for Health Research (NIHR) NHS Physical Environment Research Programme, the BIG will undertake a two-year programme that will involve simulating a ward environment using a new 80m3 aerobiological test chamber based at the university.

‘Approximately one in 10 patients pick up an infection while in hospital,’ said Prof Clive Beggs, head of the BIG. ‘While hand washing and other hygiene measures are vital, evidence suggests that these measures alone are not always enough to prevent certain infections and therefore a fresh approach is needed.’

‘We are looking at the extent to which humidity in the air enables bacteria to grow in the area. We know that Gram-negative bacteria (those that do not retain crystal violet dye when stained to distinguish between different species of bacteria) will grow in the environment and proliferate in humid conditions. Bacteria such as acinetobacter, a particular problem in intensive care units the world over, can cause fatal respiratory infections when they contaminate breathing ventilators.’

According to Beggs, such micro-organisms tend to die in low humidity, so the research will investigate the effect of reducing moisture in the air.

‘One of the things we are looking at is seeing if we can dry the air out. So it might be that we could air-condition wards and minimise the spread of these pathogens. Even if we dry them very quickly, we might be able to kill the germs off,’ he said.

There are a small number of microbiological test chambers around the world — one at Leeds University, one at Porton Down, and three in the US. One of these, at Harvard University, has a similar chamber to Bradford’s.

‘Our chamber is one of the largest in the world,’ said Beggs. ‘In a way, it is a better version of the one at Harvard because it is bigger and it can control humidity and temperature to very high standards,’ he added.

‘It enables us to carry out a whole range of experiments, where we spray aerosols and then impregnate them with micro-organisms. If we are working on, say, tuberculosis we would use a surrogate of this which is safer to use, and we would do experiments in the chamber using UV light to kill the bacteria in the air.

‘With these experiments, we can look at how we can change the environment using UV, ionisers or hydroxyl radicals (air purifiers) to clean the air and make it safe.’

To carry out experiments in the chamber, the BIG researchers are able to replicate an isolation room or a patient’s room in a hospital and test the environmentally-controlled mock-up to follow the transmission of bacteria. The average person sheds 100 million skin scales each day and each one can have up to 100 bacteria in it, including MRSA. and these skin scales can be moved around simply by drawing curtains or making a bed in the hospital.

‘We might rig up a patient’s ventilator in the chamber, and maybe a bed and a dummy patient. What we would do there is look at the movement of staff within the experiment and see how the organisms are transmitted around the room by just swabbing various surfaces. We might even rig up a curtain around a patient’s bed and as it is shaken, we can see all the bacteria that is released,’ said Beggs.

Prof Sally Davies, director-general of research and development at the Department of Health, said: ‘Preventing and controlling hospital-acquired infections is an absolute priority for patients and the NHS.

‘We need to investigate all the potential causes from every conceivable angle to make sure we are providing hospitals with the best available information and enable them to focus on priority areas.

‘The findings of this research will support NHS Trusts in the delivery of clean, safe and reliable healthcare.’

In addition to providing a test site for research carried out by the BIG, the chamber is also available for hire to companies who want to test their products in a completely sterile and controlled environment.