Investigating how streptococcus bacteria trigger endocarditis

Molecular mechanisms in Streptococcus-triggered endocarditis

Endocarditis is an infection that affects the inner lining of the heart. It is a rare but life-threatening condition, usually caused by bacteria that have entered the bloodstream and have circulated to the heart. Oral streptococci bacteria that are normally found in the plaque on our teeth can cause endocarditis, and this project aims to improve our understanding of that process. We know that streptococci can activate cells in the blood called platelets, making them clump together and form blood clots. When streptococci have infected the heart, this clotting can happen on our heart valves, which is very dangerous. Now, this Bristol research project – which teams oral microbiologists with platelet experts – will examine exactly how the bacteria have this effect on platelets. They’ve already shown that it’s controlled by two proteins on the surface of streptococci, known as PadA and Hsa, but it’s not yet clear how this works. To reveal the process, the researchers will genetically engineer bacteria to change this important pair of proteins. They will examine the impact of these changes in rabbits, and on the behaviour of platelets in blood samples. It is hoped this will reveal new insights into bacterial endocarditis, and open new avenues for effective prevention and treatments.