Clinically significant Streptococcus anginosus (Streptococcus milleri) infections: a review of 186 cases.

We describe clinically significant infections due to Streptococcus anginosus in 186 patients; 114 (61.3%) males and 72 (38.7%) females, median age 42 years, range 9 months to 93 years. In 101 (54.3%) cases S anginosus alone caused infection and in 85 (45.7%) cases it was associated with other microorganisms. Abscesses accounted for 110 (59.1%) infections. Sites of infection were: miscellaneous skin and soft tissue, 64 (34.4%), intraabdominal 41 (22%), head and neck 34 (18.3%), pleuropulmonary 22 (11.8%), genitourinary 9 (4.8%), musculoskeletal 6 (3.2%), endocarditis 5 (2.7%) and primary bacteraemia 5 (2.7%). Treatment consisted of antibiotic therapy which was often prolonged, median 30 days, range 2-90 days, and surgery in 159 (85.5%). S anginosus infection was a contributory factor in two of the three deaths which occurred.