BACKGROUND: Open facture is easy to induce infection, which is an urgent problem in clinic. Establishing a reliable animal model of open fracture with infection is of great significance for drug and instrument development and application. OBEJCTIVE: To develop an open fracture with infection model in New Zealand white rabbits, and to identify the available number of bacteria that can cause infection. METHODS: The amount of bacteria was determined by establishing open fracture structure and verifying the concentration of bacterial colonies. Thirty New Zealand white rabbits were randomly divided into control group and four experimental groups, and a transverse fracture at the middle part of tibia was established in all rabbits,followed by the injection of 1 mL of normal saline or 1mL of Staphylococcus aureus suspension at the concentrations of 1×105, 1×106, 5×106, and 1×107CFU/mL. Afterwards, the optimal concentration of 1 mL of bacteria liquid causing infection was determined by gross observation, body temperature analysis and body mass measurement, white blood cell and C-reactive protein detection, bacterial culture and pathological observation. RESULTS AND CONCLUSION: Rabbits in the 5×106CFU/mL group were all infected and had higher survival rate. In the 1×105and 1×106CFU/mL groups, some rabbits showed no infection. One rabbit died due to infection in the 1×107CFU/mL group. In summary, the reliable infection model of open fracture can be induced by injected with 1 mL of Staphylococcus aureus at the concentration of 5×106CFU/mL in New Zealand white rabbits, which can be used as an effective model to guide drugs and instruments related anti-infective research.%背景:开放性骨折有着很高的感染率,是临床上非常棘手的问题.建立可靠的开放性骨折感染动物模型,能有利于指导药物及器械在该方面的研究及临床应用.目的:建立小动物新西兰大耳白兔的开放性骨折感染模型,确定可使用的能导致开放性骨折感染的最适合细菌数量.方法:通过建立开放性骨折结构及调节菌群的浓度来确定感染所需的可确认用菌量,取新西兰大耳白兔30只,建立1个对照组和4个实验组,在胫骨中段形成胫骨横断骨折模型,分别注入生理盐水及浓度分别为1×105,1×106,5×106,1×107CFU/mL的金黄色葡萄球菌悬液1 mL.造模后通过大体观察、体温体质量分析、血白细胞和C-反应蛋白检测及细菌培养和病理组织切片分析,确定1 mL用量导致机体感染的最佳使用细菌浓度.结果与结论:①5×106CFU/mL组所有兔子感染并且存活率高;1×105CFU/mL,1×106CFU/mL 2组部分动物未发生感染;1×107CFU/mL组有1只新西兰兔因感染而死亡;②使用5×106CFU/mL浓度的金黄色葡萄球菌1 mL,可建立稳定的新西兰兔开放性骨折感染模型,可用于指导其他药物及器械等治疗手段在治疗感染过程中作为治疗感染有效性的模型使用.
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