This case illustrates several important principles. Initially, this man was predisposed to infection of his toe due to impairment of the vascular and nervous supply to the lower limbs in long-standing diabetes mellitus. The bacterium Staphylococcus aureus ("golden staph") infected the toe, eventually requiring amputation. However, some of these virulent bacteria entered the bloodstream and attached to the previously normal mitral valve, inducing acute inflammation and the formation of a large, thrombotic vegetation, with rupture of the underlying valve cusp. The bacteria constantly entered the bloodstream from this vegetation, causing septicaemia. Some of the infected, thrombotic material broke off and lodged in arteries in the spleen, kidneys and brain, causing the septic infarcts (areas of dead tissue) found at autopsy.