Doub James B, Putnam Nicole
The Doub Laboratory of Translational Bacterial Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Infect Dis Rep. 2024 Jul 18;16(4):608-614. doi: 10.3390/idr16040046.
Bacterial aggregation has been well described to occur in synovial fluid, but it is unknown if bacteria form aggregates in body fluids beyond the synovial fluid. Consequently, this translational study evaluated the ability to form bacterial aggregates in different pleural fluids. Four of the most common causes of thoracic empyema-, , , and -were used here. The different pleural fluids included one transudative and two exudative pleural fluids. Twenty-four-well microwell plates were used to form the aggregates with the aid of an incubating shaker at different dynamic conditions (120 RPM, 30 RPM, and static). The aggregates were then visualized with SEM and evaluated for antibiotic resistance and the ability of tissue plasminogen activator (TPA) to dissolve the aggregates. Statistical comparisons were made between the different groups. Bacterial aggregates formed at high shaking speeds in all pleural fluid types, but no aggregates were seen in TSB. When a low shaking speed (30 RPM) was used, only exudative pleural fluid with a high protein content formed aggregates. No aggregates formed under static conditions. Furthermore, there was a statistical difference in the CFU/mL of bacteria present after antibiotics were administered compared to bacteria with no antibiotics ( < 0.005) and when TPA plus antibiotics were administered compared to antibiotics alone ( < 0.005). This study shows that bacteria can form aggregates in pleural fluid and at dynamic conditions similar to those seen in vivo with thoracic empyema. Importantly, this study provides a pathophysiological underpinning for the reason why antibiotics alone have a limited utility in treating empyema.
细菌聚集在滑液中已有详细描述，但细菌是否会在滑液以外的体液中形成聚集体尚不清楚。因此，这项转化研究评估了细菌在不同胸腔积液中形成聚集体的能力。这里使用了胸腔积脓最常见的四种病因——[此处缺失四种病因具体内容]。不同的胸腔积液包括一种漏出液和两种渗出液。使用24孔微孔板，借助培养摇床在不同动态条件下（120转/分钟、30转/分钟和静态）形成聚集体。然后用扫描电子显微镜观察聚集体，并评估其抗生素耐药性以及组织纤溶酶原激活剂（TPA）溶解聚集体的能力。对不同组进行了统计学比较。在所有类型的胸腔积液中，细菌在高振荡速度下形成聚集体，但在胰蛋白胨大豆肉汤（TSB）中未观察到聚集体。当使用低振荡速度（30转/分钟）时，只有高蛋白含量的渗出液形成聚集体。在静态条件下未形成聚集体。此外，与未使用抗生素的细菌相比，使用抗生素后存在的细菌菌落形成单位/毫升（CFU/mL）有统计学差异（P<0.005），与单独使用抗生素相比，使用TPA加抗生素时也有统计学差异（P<0.005）。这项研究表明，细菌可以在胸腔积液中以及在与胸腔积脓体内情况相似的动态条件下形成聚集体。重要的是，这项研究为单独使用抗生素治疗积脓效用有限的原因提供了病理生理学依据。
