AO Research Institute Davos, AO Foundation, Clavadelerstrasse 8, Davos Platz, 7270, Switzerland.
Eur Cell Mater. 2017 Nov 21;34:321-340. doi: 10.22203/eCM.v034a20.
Fracture-related infection (FRI) is a major complication in surgically fixed fractures. Instability of the fracture after fixation is considered a risk factor for infection; however, few experimental data are available confirming this belief. To study whether stable fractures led to higher infection clearance, mouse femoral osteotomies were fixed with either stable or unstable fixation and the surgical site was contaminated with either Staphylococcus epidermidis (S. epidermidis)or Staphylococcus aureus (S. aureus)clinical isolates. Infection progression was assessed at different time points by quantitative bacteriology, total cell counts in spleen and lymph node and histological analysis. Operated, non-inoculated mice were used as controls. Two inbred mouse strains (C57BL/6 and BALB/c) were included in the study to determine the influence of different host background in the outcome. Stable fixation allowed a higher proportion of C57BL/6 mice to clear S. epidermidis inoculation in comparison to unstable fixation. No difference associated with fixation type was observed for BALB/c mice. Inoculation with S. aureus resulted in a more severe infection for both stable and unstable fractures in both mouse strains; however, significant osteolysis around the screws rendered the stable group functionally unstable. Our results suggested that fracture stability could have an influence on S. epidermidis infection, although host factors also played a role. No differences were observed when using S. aureus, due to a more severe infection, leading to osteolysis and loss of stability in both groups. Further studies are required in order to address the biological features underlying the differences observed.
骨折相关感染（FRI）是手术固定骨折的主要并发症。固定后骨折的不稳定被认为是感染的危险因素；然而，很少有实验数据证实这一观点。为了研究稳定的骨折是否会导致更高的感染清除率，对小鼠股骨骨折进行了稳定或不稳定固定，并将手术部位用表皮葡萄球菌（S. epidermidis）或金黄色葡萄球菌（S. aureus）临床分离株污染。通过定量细菌学、脾脏和淋巴结总细胞计数和组织学分析，在不同时间点评估感染进展情况。对未接种的手术小鼠作为对照。本研究纳入了两种近交系小鼠（C57BL/6 和 BALB/c），以确定不同宿主背景对结果的影响。与不稳定固定相比，稳定固定允许更高比例的 C57BL/6 小鼠清除表皮葡萄球菌接种。对于 BALB/c 小鼠，未观察到与固定类型相关的差异。接种金黄色葡萄球菌后，两种小鼠品系的稳定和不稳定骨折均导致更严重的感染；然而，螺钉周围的明显骨溶解使稳定组在功能上不稳定。我们的结果表明，骨折稳定性可能对表皮葡萄球菌感染有影响，尽管宿主因素也起作用。由于感染更严重，导致两组均发生骨溶解和稳定性丧失，因此使用金黄色葡萄球菌时未观察到差异。需要进一步研究以阐明观察到的差异的生物学特征。
