Characterising novel biomarkers for use in point of need sensors: A Clostridium difficile case study

Clostridium difficile infection (CDI) is the leading cause of nosocomial diarrhoea in the developed world and community-acquired infection, especially in elderly care homes, is increasing. The current "gold standard" for diagnosing CDI is stool culture, followed by a cell cytotoxicity neutralisation assay. However, these methods are labour intensive and time consuming, so are seldom used. More rapid means of diagnosing CDI, for example toxin enzyme immunoassays, are less sensitive and/or specific. Accurate and early detection, especially point of need (PoN), is crucial for the successful treatment of CDI and minimising transmission of the disease between patients.

In this study, a novel bioinformatics pipeline together with great computational power enabled the mining of all genomic data provided within the NCBI RefSeq database. The pipeline was utilised to identify a biomarker that was expressed on the surface of C. difficile, enabling PoN detection of whole cells and minimising the need for time consuming pre-treatment of samples. For use in a highly sensitive PoN test, it was important that the biomarker was common to all C. difficile strains, yet found within no other organism.