[Three cases of liver abscess associated with the Streptococcus anginosus group].

Reports of pyogenic liver abscess (PLA) caused by the Streptococcus anginosus group (SAG) have increased. Coinfection with SAG and anaerobic bacteria enhances the tendency for abscess formation. Furthermore, it has been reported that SAG infection results in pylethrombophlebitis as a complication. We experienced 3 cases of PLA caused by SAG: one case was complicated by the development of pylethrombophlebitis and the other 2 cases had coinfection with anaerobic bacteria. We report these cases together with bibliographic consideration of 23 cases previously reported in Japan.