A bedside, real time detection assay for Clostridium difficile in the faeces of hospitalized patients.
Clostridium difficile represents a significant cause of morbidity and mortality in hospitalized patients. The ability to rapidly (<60 seconds) detect the presence of the organism in the gut of an individual upon admission would enable healthcare professionals to tailor their treatment regumine accordingly. We propose to develop a bed side test capable of detecting the presence of C.difficile (spore and vegetative form) in clinical samples. This will be achieved by incorporating unique genetic signatures for the organism into a platform previously developed to detect Bacillus anthracis using and approached called Microwave-Accelerated Metal Enhanced Fluorescence (see attached paper). This technology was developed by Dr Chris Geddes of the University of Maryland Biotechnology Institute who has agreed to participate in this work and will provide funding to enable the researcher to spend time in his laboratory in Baltimore developing the assay.
Aims of Project
1.To identify C.difficile specific genetic signatures and confirm their specificity.
Using a bioinformatic based approach we will identify conserved gene targets within toxin A (tcdA) and toxin B (tcdB), the two major virulence factors of the organism. We will focus on the A1 and A2 regions of toxin A and the B2 region of toxin B (Rupnik et al 1998). Targets specific for both toxins will be included in the assay as virulent strains lacking either toxin have been reported. Using this information we will design a series of detection probes which will be screened for specificity against an extensive collection of C.difficile isolates held by Dr Jon Brazier at the National Anaerobic Reference Unit at University of Wales Hospital in Cardiff. Dr Brazier has graciously agreed to participate in this project.
2. Construct a prototype detector and determine its ability to detect target DNA.
Candidate probes identified during objective one will be engineered into the detector platform in collaboration with Professor Geddes and assessed for their ability to detection target DNA in single target and multiplex configuration.
3. Determine the ability to the detector platform to identify the presence of C.difficile in biological fluids. The sensitivity of the assay in the presence of a biological matrix will be determined in vitro by spiking biological fluids with known concentrations of the organism.
4. Determine the ability of the detector platform to detect C.difficile in clinical samples. In collaboration with Dr Robin Howe at the national Public Health Service for Wales we will determine the ability of the assay to detect the presence of C.difficile.
Training benefit to the student.
The proposed program of research will enable the student to develop a multidisciplinary research skill set encompassing microbiology, molecular biology and physics. It offers a unique opportunity to understand the issues and challenges of working with other disciplines and the importance of developing a common language set. Given the current emphasis on interdisciplinary approaches and the benefits they are likely to yield, the successful student will be well placed to make a positive contribution in this area. In addition the opportunity to spend time in the Geddes lab in Baltimore will be an enriching experience both intellectually and socially.
The organism Clostridium difficile is a significant causes of morbidity and mortality amongst hospitalized patients in Wales accounting for considerably more infections than MRSA. To combat the threat posed by C.difficile there is a pressing need to develop effective diagnostic tools, environmental decontamination strategies and therapeutics to treat at risk and infected individuals. To address theses issues we are in the process of establishing a new C.difficile research group which will, in collaboration with healthcare, academic and industrial partners, develop three complimentary research focuses namely detection, decontamination and treatment/anti-infectives.
To underpin this effort we have established a strategic link with Dr Jon Brazier the head of the National Anaerobe Reference Unit which is based at the Heath and hosts an extensively collection of C.difficile isolates. We have also established a link with Dr Robin Howe a consultant Microbiologist at the National Public Health Service Microbiology Laboratory which is also based at the University Hospital. Robin has a long term interest in C.difficile and has kindly agreed to provide access to clinical samples in addition to acting as a co-supervisor of the student. Building collaborative links with our public health and clinical colleagues across the university can only strengthen the relevance of our research effort and its is our expectation that it will lead to future joint research in this and other areas.
The involvement of Professor Geddes is a key element of this proposal and represents an extension of an existing research relationship. As the project progresses it is out intention to investigate the possibility of joint research proposals to US funding bodies such as the National Institutes of Health and the National Science Foundation. Indeed the technology has the potential to be adapted to detect a range of agents once specific diagnostic signatures have been identified.