Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device
Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device
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DOI：
10.1128/iai.00745-19
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发表时间：
2019-12-01
影响因子：
3.1
通讯作者：
Stewart, Philip S.
中科院分区：
文献类型：
--
作者：
Ghimire, Niranjan;Pettygrove, Brian A.;Stewart, Philip S.
利用激光延时共聚焦扫描显微镜，体外检测了人中性粒细胞清除血清镀膜玻璃表面新附着的金黄色葡萄球菌的能力。定量图像分析用于测量细菌生物量、中性粒细胞运动和中性粒细胞控制的表面积的时间变化。在对照实验中，表面接种细菌但不添加中性粒细胞，观察到大量细菌生长。中性粒细胞能够控制细菌的生长，但只有当中性粒细胞/细菌数量比超过约1时才能持续控制。当预先附着的细菌在加入中性粒细胞之前被给予领先优势并允许生长3小时时，中性粒细胞无法维持对新生生物膜的控制。在这些先行实验中，形成了面积为50 μ m(2)或更大的细菌生物膜聚集体，即使多个中性粒细胞攻击一个聚集体，这种聚集体的生长仍在继续。这些结果提出了一种生物膜感染启动的模型，其中中性粒细胞向非生物表面募集的延迟使表面附着的细菌有时间生长并形成聚集体，从而免受中性粒细胞的清除。中性粒细胞-生物膜表面竞争计算模型的结果支持这一概念模型，并强调了相互作用的随机性。此外，我们观察到，当氧张力降低到0%或2% O-2时，中性粒细胞的运动和细菌的清除都受到损害。
The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using timelapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil/bacterium number ratio exceeded approximately 1. When preattached bacteria were given a head start and allowed to grow for 3 h prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head-start experiments, aggregates of bacterial biofilm with areas of 50 mu m(2) or larger formed, and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O-2.