Infective endocarditis caused by Streptococcus sinensis diagnosed with next-generation sequencing: a case report and literature review.

Abstract

Background: Infective endocarditis (IE) caused by Streptococcus sinensis is rare and challenging to diagnose due to the irregular use of antibiotics and the limitations of conventional diagnostic methods. Metagenomaic next-generation sequencing (mNGS) has emerged as a valuable diagnostic tool, offering significantly enhanced accuracy in identifying elusive pathogens, particularly in blood culture-negative endocarditis (BCNE).

Case presentation: We reported the case of a 33-year-old male who presented with recurrent intermittent fever lasting over six months. Despite multiple diagnostic attempts, including blood cultures, no causative pathogen was identified. Blood mNGS revealed the presence of S. sinensis, a rare pathogen associated with IE. Echocardiography confirmed vegetation on the mitral and aortic valves, leading to a possible diagnosis of IE. The patient underwent successful surgical valve replacement, and subsequent mNGS of excised valve tissue confirmed the presence of S. sinensis. We administered a tailored antibiotic regimen, and the patient achieved a favorable recovery with no significant complications during follow-up.

Results: We identified 11 additional cases of S. sinensis-induced IE through a literature review, including patients from diverse geographic regions and age groups. Most cases were associated with prior dental procedures or poor oral health. Common diagnostic methods included blood culture and 16 S rRNA sequencing, while recent cases utilized mNGS. Treatment typically involved penicillin-based antibiotics combined with gentamicin, with surgical intervention in most cases leading to favorable outcomes.

Conclusions: This case highlights the diagnostic value of mNGS in identifying pathogens in IE, particularly when traditional methods fail due to prior antibiotic use. While mNGS has significant advantages in pathogen detection, it cannot replace standard microbiological techniques and should be considered a complementary approach. Integrating mNGS into clinical workflows can improve diagnostic accuracy, especially in BCNE cases, and guide effective treatment strategies.

Clinical trial number: Not applicable.