Virulence factors in streptococcal infective endocarditis

Infective endocarditis (IE) is a life threatening, endovascular infection occurring when bacteria enter the blood stream and adhere to heart valves. Mortality rates remain in the range of 11-27%. The most common infecting micro-organisms are now the staphylococci (44%) although streptococci (31%) and particularly the oral streptococci (21%) are still major causative agents. Many different oral streptococci have been isolated from IE cases, the most common being Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, Streptococcus mitis, Streptococcus anginosus group and mutans streptococci.