*Extremity Trauma and Regenerative Medicine, US Army Institute of Surgical Research, San Antonio, TX; †Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham, United Kingdom; and ‡Infectious Disease Service, Brooke Army Medical Center, San Antonio, TX.
J Orthop Trauma. 2014 Jun;28(6):370-5. doi: 10.1097/BOT.0b013e3182a7739e.
Local delivery allows a high concentration of antibiotics to be achieved in the wound while avoiding the side effects and cost of systemic administration. Beads molded from polymethylmethacrylate cement are commonly used for local antibiotic delivery but are not ideal. The purpose of this study was to determine whether a bioabsorbable gel delivering vancomycin and gentamicin is more effective in reducing infection than beads delivering vancomycin and tobramycin.
This study used a segmental defect rat model contaminated with Staphylococcus aureus and treated with clinically relevant local antibiotic doses, delivered by gel or beads. In the gel group, 1 mL of gel containing gentamicin and vancomycin was spread throughout the wound. In the bead group, four 3-mm beads containing tobramycin and vancomycin were placed in the wound, 2 in the defect and 2 in the adjacent tissue envelope, there was also a control group that received no antibiotic treatment. After 14 days, bone and hardware was harvested for separate microbiological analysis.
There was a significantly lower infection rate in groups treated with antibiotics delivered by gel compared with those treated with either antibiotic beads or no antibiotics at all (P < 0.001). Quantitative cultures also demonstrate significantly less bacteria in the wounds treated with the gel than in the control or bead groups (P ≤ 0.004).
These results suggest that antibiotic delivery by a gel is superior to beads. The authors propose that antibiotic depot by polymethylmethacrylate antibiotic beads is less effective because this method has to rely on diffusion of the antibiotic from the high concentration close to the beads to all regions of the wound.
局部给药可使抗生素在伤口中达到高浓度，同时避免全身给药的副作用和成本。聚甲基丙烯酸甲酯水泥模制的珠粒常用于局部抗生素给药，但并不理想。本研究旨在确定载万古霉素和庆大霉素的可生物吸收凝胶是否比载万古霉素和妥布霉素的珠粒更能有效减少感染。
本研究使用节段性缺损大鼠模型，用金黄色葡萄球菌污染，并采用临床相关的局部抗生素剂量，通过凝胶或珠粒给药。在凝胶组中，将 1 毫升含有庆大霉素和万古霉素的凝胶涂满整个伤口。在珠粒组中，将四个含有妥布霉素和万古霉素的 3 毫米珠粒放置在伤口中，2 个在缺损处，2 个在相邻的组织包膜中，还有一个对照组不接受任何抗生素治疗。14 天后，采集骨和硬件进行单独的微生物分析。
与抗生素珠粒治疗组或未接受抗生素治疗组相比，用凝胶治疗的感染率明显降低（P<0.001）。定量培养也表明，与对照组或珠粒组相比，凝胶治疗组的伤口中细菌数量明显减少（P≤0.004）。
这些结果表明，凝胶给药的抗生素优于珠粒。作者提出，聚甲基丙烯酸甲酯抗生素珠粒的抗生素储存效果较差，因为这种方法必须依靠抗生素从珠粒附近的高浓度扩散到伤口的所有区域。
