兔关节内植物植入术后金黄色葡萄球菌感染模型的建立

目的探索人工关节置换术后金黄色葡萄球菌假体周围感染感染，可靠动物模型的建立方法，比较细菌数量与模型的关系，观察模型建立后实验动物的生存率，以及后期细菌毒力和基因变异情况。方法60只新西兰大白兔使用定制非骨水泥假体行膝关节置换后，随机分入对照组和实验组（共5组，给予金葡菌液1ml，浓度分别为1×10^4，1×10^5，1×10^6，1×10^7，1×10^8CFU／ml）。采用大体评分、组织学、细菌生化检验、金葡菌遗传学和毒理学分析、扩增片段长度多态性（AFLP）细菌遗传物质分析的方法，验证模型构建的效率、安全性和稳定性，基线齐性检验、动物模型大体评分，浓度梯度分析采用多组间卡方分析，细菌致病基因分析采用和AFLP分析采用组间聚类分析一平均联结法方法。结果动物生存率、感染率不完全相同，组问方差分析显示，各组间存在统计学差异（F=3．695，P〈0．01）；组织学、细菌培养、生化检验和23SrRNA基因、nile基因检测支持金葡菌感染，使用1ml，1×10^5CFU／ml金葡菌膝关节直接接种能够成功构建模型。致病基因分析和AFLP检测显示，细菌在自然繁殖过程中出现变异，但各基因变异率和基因组总体变异率低于10％。结论本研究成功构建了稳定的关节置换术后金葡菌感染动物模型，发现细菌感染初期的基因变异和毒理学改变。该模型可用于关节置换术后假体周围急性感染的相关研究。更远期的变异情况可能导致感染模型的不稳定，需进一步研究。

Animal model of staphylococcus aureusis infection after arthroplasty

Objective To explore the relationship between the bacterium and the models, observe the survival and infection rates of the animal, and detect the changes of genetic deteiminants of Staphylococcus. Methods 60 New Zealand white rabbits were performed knee arthroplasty, and divided into six groups （five experimental groups and one control group ）. Baseline homogeneity test were carried out. The control group were injected with 1 ml saline. Other five groups were injected with 1 ml bacteria liquid to the knee joint and the concentration spread from 1 × 10^4 to 10^5 CFU/ml. The general infection score, histology, bacteria biochemical test, genetics, toxicology and amplified fragment length polymorphism （AFLP） method were used to detect the efficiency, safety and stability of the models. The baseline homogeneity, general score and concentration gradient were analysed by the chi-square analysis. The bacterial pathogenic gene and the AFLP were analysed by the clustering analysis. Results The efficiency and the safety were different among groups （ F = 5. 695, P 〈 0. 01 ）. The general infection score, histology, bacteria biochemical test, and genetics all supported that the rabbit models were infected by the staphylococcus aureus successfully. Toxicology and AFLP analysis indicated that the bacteria changed during the multiplication, yet the aberration rate of the genes and the general aberration rate were less than 10%. Conclusions This study had successfully constructed the infection animal model after the arthroplasty, and discussed about the genovariation and the toxicology changes of the bacteria. Constructing joint infection animal model using 1 ml staphylococcus aureusis inocula with the concentration of 1 × 105 CFU/ml is viable. The models can be used steadily in two weeks. And the distant heteromorphosis will lead to instability of the animal model, and more explorations should be launched.