CASE REPORT article

Front. Cardiovasc. Med.

Sec. General Cardiovascular Medicine

Intraoperative Sampling for Postoperative Metagenomic Next-Generation Sequencing to Guide Biofilm-Targeted Therapy for Cutibacterium acnes Infective Endocarditis Complicated by Ruptured Sinus of Valsalva Aneurysm: A Case Report

  • 1. Qingyuan People's Hospital, Qingyuan, China

  • 2. Hefei University of Technology, Hefei, China

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Abstract

Background: Cutibacterium acnes is an easily overlooked pathogen in infective endocarditis (IE) due to its slow growth, propensity for biofilm formation, and high rate of culture-negative results. When complicated by structural heart disease such as a ruptured sinus of Valsalva aneurysm (RSVA), its indolent course can lead to severe hemodynamic compromise. Case Summary: A 35-year-old male with a known ventricular septal defect (VSD) and unruptured aortic sinus aneurysm presented with persistent fever and progressive heart failure (NYHA class IV). Echocardiography revealed a ruptured right coronary sinus of Valsalva aneurysm (RCSVA) into the right ventricular outflow tract (RVOT) with a large vegetation. Blood cultures were negative. After 6 days of ineffective empirical antibiotic therapy, emergency surgery was performed to resect the aneurysm and vegetation and repair the cardiac structures. Intraoperatively, a vegetation sample was collected for metagenomic next-generation sequencing (mNGS). Postoperatively, mNGS identified Cutibacterium acnes with high sequence reads (1,284) and coverage (47.62%), enabling a definitive diagnosis. Pathology confirmed microcolonies and necrotic inflammation. The antibiotic regimen was switched to a regimen with potential activity against biofilms with oral doxycycline and intravenous clindamycin for 6 weeks. The patient's inflammatory markers normalized, and cardiac function recovered to NYHA class I, with no recurrence at 12-month follow-up. Conclusion: This case highlights the diagnostic synergy of intraoperative histopathology and mNGS for pathogen identification, underscores the rationale for biofilm-conscious adjuvant therapy, and reaffirms the crucial role of early surgical debridement and repair in achieving cure.

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Keywords

Biofilm, Cutibacterium acnes, Infective endocarditis, metagenomic next-generation sequencing, ruptured sinus of Valsalva aneurysms

Received

18 September 2025

Accepted

09 February 2026

Copyright

© 2026 Liu and Wu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Jie Liu

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