Viridans streptococcal endocarditis: clinical, microbiological, and echocardiographic correlations

J Infect Dis. 1986 Oct;154(4):597-603. doi: 10.1093/infdis/154.4.597.


Infections caused by species within the viridans streptococci have been associated with different clinical characteristics. We studied 36 patients with viridans streptococcal endocarditis. Complications were seen in 10 (32%) of 31 patients with native valve endocarditis and four (80%) of five with prosthetic valve endocarditis and included death in two, valve replacement in six, persistent infection in three, emboli in two, and congestive heart failure in nine. Two-dimensional echocardiograms demonstrated vegetations in 26 (72%) of 36, flail mitral valves in seven, disruption of aortic valve prosthesis in one, and perivalvular abscesses in three (two Streptococcus sanguis I and one Streptococcus intermedius I). All twelve patients with native valve endocarditis who suffered complications had vegetations detected by two-dimensional echocardiography, whereas seven patients with native valve endocarditis without vegetations, as detected by two-dimensional echocardiography, had no complications (P = .03). We found no significant correlation between streptococcal species and clinical outcome. To confirm our identifications, we sent 16 identical viridans streptococcal endocarditis isolates to five institutions; only three of 16 were identified as the same species by all five institutions. We conclude that viridans streptococcal endocarditis can be associated with a virulent clinical course and that there is marked variability in species designations of individual strains by different laboratories.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Echocardiography
  • Endocarditis, Bacterial / complications
  • Endocarditis, Bacterial / microbiology*
  • Female
  • Heart Failure / etiology
  • Heart Valve Diseases / complications
  • Heart Valve Diseases / microbiology*
  • Heart Valve Prosthesis*
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Streptococcal Infections / complications
  • Streptococcal Infections / microbiology*
  • Streptococcus / classification
  • Streptococcus / isolation & purification
  • Streptococcus sanguis / classification
  • Streptococcus sanguis / isolation & purification