Bacteremia involving the ‘‘Streptococcus milleri’’ group: analysis of 19 cases. Clin. Infect. Dis

During a 3-year study period, 19 patients at the University Hospital of Maastricht developed bloodstream infections with species ofthe "Streptococcus miller; " group, for an incidence of0.33 per 1,000 admissions. The patients ' median age was 48 years; the male-to-female ratio was 2.8. Eleven patients (57.9%) had underlying diseases, among which malignancy was predominant. Local trauma to the mucosal barrier was an important risk factor. An associated site of infection was found most frequently in the abdominal and thoracic cavities (nine and five cases, respec-tively). Bacteremia was polymicrobial in four of 19 episodes. The 20 infecting S. milleri strains were identified to the species level; Streptococcus anginosus was the most prevalent (16 strains). Eight strains carried Lancefield group C. The isolates were sensitive to most antibiotics. Abscess formation was documented in nine cases (47.3%); repeated drainage procedures were required in half of these episodes. Mortality was high (five of 19 patients, or 26.3%). Streptococcus intermedius. Streptococcus anginosus. and Streptococcus constellatus are collectively referred to as the "Streptococcus milleYi ' , group and are components of the flora of the mouth, gastrointestinal tract, and urogenita