BUGhunter: laser fluorescence for visualisation of bacterial contamination in a hospital environment

Lead Research Organisation: University College London
Department Name: Mullard Space Science Laboratory


The possibility of patients picking up an infection whilst spending time in hospital is one of the greatest current concerns within healthcare in this country and in the US and continental Europe. These so-called Health Care Associated Infections (HCAIs) have been estimated to contribute over 5,000 avoidable deaths within the NHS every year. One great difficulty in tackling this concerning issue is how to quickly identify cases of contamination of hospital surfaces. Microorganisms that can cause human infections, such as strains of bacteria and fungi, can persist for long periods of time on surfaces such as walls, door handles, worktops, and so on. Techniques do already exist to test for contamination around a hospital building, but these are very expensive and time-consuming, and so are rarely used except during a known outbreak. The research proposed here is a completely new approach to detecting regions of contamination in hospitals and other public healthcare buildings. It is very quick to run, and so can be used routinely to pick-up cases of contamination before they trigger widespread infections among the patients. This technique is based on a principle known as fluorescence. All living cells contain different kinds of chemical compounds that fluoresce when light is shone on them. This means that they absorb some of the energy of the incoming light, and then release a portion of this absorbed energy by giving off light of their own. Different compounds absorb different wavelengths of light best, and then also give-off the fluorescent light with a particular pattern, or spectrum, of wavelengths. So shining a laser-based torch with a very precise wavelength of light (i.e. a specific colour) across a hospital surface, and looking carefully for where fluorescent light is glowing weakly back at you will reveal where clumps of cells have contaminated the area. What's more, different kinds of cells contain different amounts of particular compounds inside them. Analyzing the exact spectrum of light given off by microorganisms when they fluoresce, and across different wavelengths of light shining on them, acts like a fingerprint of the kinds of microorganisms present. It's therefore possible in principle to work out what sorts of microorganisms there are present in the contamination. This project aims to assess whether a lighting device, the BUGhunter, could show where microbes are located in supposedly clean hospital settings to try to eradicate hospital-acquired infections. Existing methods to assess whether cleanliness standards are met rely on very slow methods involving taking samples and sending them off to a laboratory. The proposed BUGhunter system would allow documentation of the location of such microbes before and after cleaning measures have taken place to ensure compliance. The development will include an assessment of whether different types of microbes can be differentiated from one another. However, the main emphasis here is on the BUGhunter system to detect whether microbial colonies are present on clean clinical surfaces where they should not be present. It is likely that a new area of research will be opened up if it is found that infectious microorganisms can be distinguished from one another by their biofluorescent properties. For example, a biofluorescent signature may be able to differentiate between pathogenic and harmless bacteria or the number of such organisms in a particular colony or even what particular strain a pathogenic bacteria belongs to. Any or all of these would have a profound effect on modern-day clinical practice and medicine as well as opening up the possibility of providing much cleaner and salubrious environments for a wide variety of different functions such as food preparation.


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