Bacterium lassoes its way from the mouth to the heart

Researchers from the University of Bristol have now revealed a potentially key molecular process that occurs in the case of infective endocarditis, a type of cardiovascular disease in which bacteria cause unwanted blood clots to form on heart valves. If untreated, this condition is fatal and, even with treatment, mortality rates remain high (up to 30 per cent). There are over 2,000 cases of infective endocarditis in the UK annually and the incidence is rising.

The Bristol team’s findings could lead to the development of new drugs to help combat this life threatening heart disease.

A key part of the study involved use of the UK national synchrotron facility, Diamond Light Source. Using this giant X-ray microscope the team were able to visualise the structure and dynamics of a protein called CshA which, based on previous studies at Bristol University, was believed to play an important role in targeting the oral bacterium Streptococcus gordonii to the tissues of the heart. The researchers were intrigued to find that CshA acts as a ‘molecular lasso’ to enable S. gordonii to bind to the surface of human cells. Such adhesive interactions are critical first steps in the ability of this bacterium to cause disease.