Human infective endocarditis caused by Streptococcus suis serotype 2

Martin C Heidt1, Walid Mohamed, Torsten Hain

  • 1Department of Cardiovascular Surgery, Hospital of the Justus-Liebig University Giessen, Germany.

Insights

Human infective endocarditis from Streptococcus suis is rare. Molecular methods are crucial for accurate diagnosis, as S. suis mimics other bacteria on standard blood agar, preventing misidentification.

Area of Science:

  • Infectious Diseases
  • Microbiology
  • Clinical Medicine

Background:

  • Human infective endocarditis (IE) is a serious infection of the heart's inner lining.
  • Streptococcus suis (S. suis) is an emerging zoonotic pathogen, infrequently causing IE in humans.
  • Accurate and timely diagnosis of IE is critical for effective treatment and patient outcomes.

Observation:

  • A case of a 43-year-old male with life-threatening infective endocarditis caused by Streptococcus suis is presented.
  • The clinical presentation mimicked other forms of streptococcal endocarditis.
  • Microscopic and biochemical characteristics of S. suis on sheep blood agar can be confused with viridans streptococci.

Findings:

  • Standard microbiological culture methods on sheep blood agar can lead to misidentification of S. suis.
  • The resemblance of S. suis to viridans streptococci on agar plates represents a significant diagnostic pitfall.
  • Molecular identification methods were essential for the definitive diagnosis of S. suis endocarditis.

Implications:

  • This case highlights the importance of considering Streptococcus suis in the differential diagnosis of infective endocarditis, especially in patients with relevant exposure history.
  • Enhanced diagnostic strategies, including molecular techniques, are necessary to avoid delayed or incorrect treatment.
  • Increased awareness and improved diagnostic accuracy for S. suis infections can lead to better patient management and reduced morbidity and mortality.

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