Subacute bacterial endocarditis (SBE) (also called endocarditis lenta) is a type of endocarditis (more specifically, infective endocarditis). It is usually caused by a form of streptococci viridans bacteria that normally live in the mouth and throat (Streptococcus mutans, mitis, sanguis or milleri). Other strains of streptococci (bovis and equines) can also cause subacute endocarditis, usually in patients who have a form of gastrointestinal cancer. Additional causes are Enterococci (urinary tract infections) and coagulase negative staphylococci such as Staphylococcus epidermidis (skin). Underlying structural valve disease is usually present in patients before developing subacute endocarditis. It is less likely to lead to septic emboli than is acute endocarditis, but subacute endocarditis has a relatively slow process of infection and, if left untreated, can worsen for up to one year before it is fatal.