Clostridioides difficile
The large intestine harbours more microbes than anywhere else in the human body, totalling approximately 0.3% of your body weight! Some of these microbes are beneficial bacteria that form communities growing together in biofilms, along the mucosal surface of the human intestinal cells. These biofilms are encased in a protective matrix. Biofilms of good microbes help to provide our body with energy and regulate our immune system. However, pathogenic bacteria can hide in these biofilms, and cause disease.
One such bacterium is Clostridioides difficile (often shortened to C.diff), which produces at least two toxins that destroy intestinal cells and, if left unchecked, can result in death. C.diff infection is the most common cause of diarrhoea, affecting approximately 13,000 people per year. Antibiotic therapy can kill C.diff cells but, by hiding amongst the biofilm community, infections can bounce back, causing repeated relapses over long periods of time.
Therapies include antibiotic treatment. However, up to 30% of cases are not cured by primary therapy, resulting in recurrent disease; this increases patient morbidity and places a burden on healthcare systems globally. We have little understanding of why these therapies fail.
Using a clinically-validated in vitro gut model, scientists at the University of Leeds (https://medicinehealth.leeds.ac.uk/medicine/staff/176/dr-anthony-buckley) found that C.diff spores and vegetative cells became entwined with the gut biofilm community, and that treatment with the antimicrobial vancomycin, did not effectively remove the cells when they were within the biofilm.
Microbial communities in the gut interact with C.diff to either encourage or prevent their uptake into biofilms; we are exploring ways to encourage interactions between gut microbes and C.diff that prevent recurrent infections.
Further reading on Clostridioides difficile biofilms
Normington, C., Moura, I. B., Bryant, J. A., Ewin, D. J., Clark, E. V., Kettle, M. J., Harris, H. C., Spittal, W., Davis, G., Henn, M. R., Ford, C. B., Wilcox, M. H. and Buckley, A. M. (2021) ‘Biofilms harbour Clostridioides difficile, serving as a reservoir for recurrent infection’, npj Biofilms and Microbiomes, vol. 7(1), https://doi.org/10.1038/s41522-021-00184-w.