C. difficile- a Gram positive, spore forming, toxin producing, anaerobic bacteria is responsible for causing C. difficile associated diarrhoea (CDAD). Prolonged use of antibiotics combined with long stays in hospitals and other healthcare facilities are the main factors responsible for occurrence of the disease.

Treatment of CDAD, particularly by antibiotics is problematic due to the organism’s ability to develop resistance; therefore alternative methods of treatment are being sought. Bacteriophages (phages) are viruses that target and infect bacteria, and phage therapy (use of phages to treat bacterial infection) has shown promise due to its advantages over standard antibiotics including high efficiency, minimal disruption of the natural intestinal microbiota and ability to infect antibiotic resistant bacteria.

To date, no work has been carried out on understanding phage-C. difficile interactions in human gut epithelial cells, therefore an ex situ model has been developed to mimic phage therapy. This will be used to determine how phages impact the ability of clinically relevant C. difficile strains to colonise mammalian cells, to establish how phages influence C. difficile growth and biofilm formation and to ascertain the inflammatory responses of epithelial cells that may be triggered by phage. Results have shown that C. difficile levels drop in the presence of both phage and epithelial cells compared to with phage alone.