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Streptococcus intermedius causing infective endocarditis and abscesses: a report of three cases and review of the literature

MaryAnn P Tran1, Molly Caldwell-McMillan2, Walid Khalife3 and Vincent B Young145*

  • * Corresponding author: Vincent B Young

  • † Equal contributors

Author Affiliations

1 Department of Medicine, Infectious Diseases Division, Michigan State University, East Lansing, Michigan, USA

2 Department of Medicine, Michigan State University, East Lansing, Michigan, USA

3 Department of Microbiology, Sparrow Health Systems, Lansing, Michigan, USA

4 Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA

5 National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan, USA

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BMC Infectious Diseases 2008, 8:154  doi:10.1186/1471-2334-8-154

Published: 10 November 2008



Streptococcus intermedius is a member of the Streptococcus anginosus group. Clinical disease with S. intermedius is characterized by abscess formation and rarely endocarditis. Identification of Streptococcus intermedius is difficult, leading to the development of molecular methods to more accurately identify and characterize this organism.

Case presentation

Over a period of 6 months we encountered three cases of invasive Streptococcus intermedius infection presenting as hepatic abscesses, brain abscess, and endocarditis. We confirmed our microbiologic diagnosis through 16S sequencing and found a common virulence gene in each case.


Our report illustrates three different clinical manifestations due to Streptococcus intermedius infection that can be encountered in healthy individuals in a community hospital setting. To our knowledge, this is the first case of Streptococcus intermedius endocarditis confirmed by 16S sequencing analysis. The use of molecular methods may allow a better understanding of the epidemiology and pathogenesis of this organism.