Oukrich Safae, Hong Jane, Leon-Grooters Mariël, van Cappellen Wiggert A, Slotman Johan A, Koenderink Gijsje H, van Wamel Willem J B, de Maat Moniek P M, Kooiman Klazina, Lattwein Kirby R
Biomedical Engineering, Department of Cardiology, Cardiovascular Institute, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
Erasmus Optical Imaging Center, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
Biofilm. 2025 Feb 7;9:100261. doi: 10.1016/j.bioflm.2025.100261. eCollection 2025 Jun.
The single most common microbe causing cardiovascular infections is (). produces coagulase that converts fibrinogen to fibrin, which is incorporated into biofilms. This process aids in adherence to intravascular structures, defense against the host immune system, and resistance to antimicrobial treatment. Despite its significance, fibrin formation in biofilms remains poorly understood. Therefore, this study aimed to elucidate the early development of cardiovascular biofilms. Clinically isolated coagulase-positive and coagulase-negative () from patients with cardiovascular infections, and a coagulase mutant Δcoa, were grown in tryptic soy broth (TSB), Iscove's Modified Dulbecco's Medium (IMDM), and pooled human plasma, with or without porcine heart valves. Bacterial growth, metabolic activity, and bacterial fibrinogen utilization were measured over 24 h at 37 °C. Time-lapse confocal microscopy was used to visualize and track biofilm development. exhibited more growth in TSB and human plasma than and Δcoa, but showed similar growth in IMDM after 24 h. Peak metabolic activity for all isolates was highest in TSB and lowest in human plasma. The presence of porcine valves caused strain-dependent alterations in time to peak metabolic activity. Confocal imaging revealed fibrin-based biofilm development exclusively in the coagulase-producing strains. Between 2 and 6 h of biofilm development, 74.9 % (p = 0.034) of the fibrinogen from the medium was converted to fibrin. Variations in fibrin network porosity and density were observed among different coagulase-producing strains. Fibrin formation is mediated by coagulase and first strands occurred within 3 h for clinical strains after exposure to human plasma. This study stresses the importance of experimental design given the bacterial changes due to different media and substrates and provides insights into the early pathogenesis of cardiovascular biofilms.
引起心血管感染最常见的单一微生物是（）。（该微生物）产生凝固酶，可将纤维蛋白原转化为纤维蛋白，纤维蛋白会整合到生物膜中。这一过程有助于其黏附于血管内结构、抵御宿主免疫系统并对抗菌治疗产生抗性。尽管其具有重要意义，但生物膜中纤维蛋白的形成仍知之甚少。因此，本研究旨在阐明心血管生物膜的早期形成过程。从心血管感染患者中临床分离出凝固酶阳性的（该微生物）和凝固酶阴性的（另一种微生物），以及一种凝固酶突变体Δcoa，将它们分别在胰蛋白胨大豆肉汤（TSB）、伊思柯夫改良杜氏培养基（IMDM）和混合人血浆中培养，有无猪心脏瓣膜参与培养。在37℃下，对细菌生长、代谢活性和细菌纤维蛋白原利用情况进行24小时监测。采用延时共聚焦显微镜观察并追踪生物膜的形成过程。（该微生物）在TSB和人血浆中的生长情况比（另一种微生物）和Δcoa更好，但在24小时后在IMDM中的生长情况相似。所有分离株的代谢活性峰值在TSB中最高，在人血浆中最低。猪瓣膜的存在导致代谢活性峰值出现时间因菌株而异。共聚焦成像显示，仅在产生凝固酶的（该微生物）菌株中出现了基于纤维蛋白的生物膜形成。在生物膜形成的2至6小时内，培养基中74.9%（p = 0.034）的纤维蛋白原转化为纤维蛋白。在不同产生凝固酶的（该微生物）菌株中观察到纤维蛋白网络孔隙率和密度的差异。纤维蛋白的形成由（该微生物）凝固酶介导，临床菌株在接触人血浆后3小时内出现首批纤维蛋白链。鉴于不同培养基和底物会导致细菌发生变化，本研究强调了实验设计的重要性，并为（该微生物）心血管生物膜的早期发病机制提供了见解。
