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

在美国、美国和欧洲大陆，患者在住院期间感染的可能性是目前医疗保健领域最令人担忧的问题之一。据估计，这些所谓的卫生保健相关感染(HCAI)每年导致NHS内5000多例本可避免的死亡。解决这一令人担忧的问题的一大困难是如何快速识别医院表面受到污染的病例。可能导致人类感染的微生物，如细菌和真菌菌株，可以在墙壁、门把手、工作台等表面持续很长时间。目前确实存在检测医院大楼周围污染的技术，但这些技术非常昂贵和耗时，因此除非在已知的疫情爆发期间，否则很少使用。这里提出的这项研究是一种全新的方法来检测医院和其他公共医疗保健建筑中的污染区域。它的运行速度非常快，因此可以常规用于在患者中引发广泛感染之前发现污染病例。这项技术是基于一种称为荧光的原理。所有活着的细胞都含有不同种类的化合物，当光线照射到它们身上时，这些化合物会发出荧光。这意味着它们吸收了入射光的部分能量，然后通过发出自己的光释放了一部分吸收的能量。不同的化合物最好地吸收不同波长的光，然后也发出具有特定波长图案或光谱的荧光。因此，用一种非常精确的光波长(即特定的颜色)照射基于激光的手电筒，穿过医院表面，仔细观察荧光灯在哪里微弱地反光，就会发现哪里有成团的细胞污染了这一区域。更重要的是，不同种类的细胞内含有不同数量的特定化合物。分析微生物发出荧光时发出的光的准确光谱，以及照射在它们身上的不同波长的光，就像是存在的微生物种类的指纹。因此，原则上有可能计算出污染中存在哪些微生物。该项目旨在评估一个照明设备，即轰鸣器，是否可以显示微生物在理应干净的医院环境中的位置，以试图根除医院获得性感染。评估是否达到清洁标准的现有方法依赖于非常缓慢的方法，即采集样本并将其送往实验室。拟议的Bughunter系统将允许记录这些微生物在采取清洁措施之前和之后的位置，以确保遵守规定。这项研究将包括评估不同类型的微生物是否可以相互区分。然而，这里主要强调的是Bughunter系统，以检测清洁的临床表面是否存在微生物菌落，而这些微生物菌落不应该存在。如果发现感染性微生物可以通过它们的生物荧光特性相互区分，很可能会开辟一个新的研究领域。例如，生物荧光特征可能能够区分致病细菌和无害细菌，或者特定菌落中此类微生物的数量，甚至能够区分病原细菌属于什么特定菌株。任何或所有这些都将对现代临床实践和医学产生深远影响，并为各种不同的功能提供更清洁和健康的环境，如准备食物。

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.