“…Until recently, viridans streptococci have been considered as the most common causative microorganisms of IE and detected at a range from 30% to 50% (Strom et al, 1998;Nakatani et al, 2003;Murdoch et al, 2004;Tleyjeh et al, 2005;Alshammary et al, 2008). Viridans streptococci are composed of a total of 21 species, including S. mitis, S. anginosus, S. salivalius, and S. bovis (Kawamura et al, 1995).…”