Bayston Roger, Brant Christine, Dombrowski Stephen M, Hall Geraldine, Tuohy Marion, Procop Gary, Luciano Mark G
Department of Neurosurgery - S80, the Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
Cerebrospinal Fluid Res. 2008 Oct 24;5:17. doi: 10.1186/1743-8454-5-17.
Detailed human studies of the mechanisms and development of shunt infection in real time are not possible, and we have developed a canine hydrocephalus model to overcome this. The intention of this pilot study was to show that the canine hydrocephalus model could be shunted using conventional "human" shunts, and that a shunt infection could be established so that further studies could then be planned.
Hydrocephalus was induced in seven dogs (Canis familiaris) by fourth ventricle obstruction. Four weeks later they were shunted using a Hakim Precision valve. Four of the dogs received shunts whose ventricular catheter had been inoculated with Staphylococcus epidermidis, and three were uninoculated controls. Four weeks after shunting the dogs were sacrificed and necropsy was performed. Removed shunts and tissue samples were examined microbiologically and isolates were subjected to detailed identification and genomic comparison.
All the dogs remained well after shunting. Examination of removed shunt components revealed S. epidermidis in the brain and throughout the shunt system in the four inoculated animals, but in two of these Staphylococcus intermedius was also found. S. intermedius was also isolated from all three "negative" controls. There were slight differences between S. intermedius strains suggesting endogenous infection rather than cross- infection from a point source.
Shunt infection was established in the canine model, and had the experiment been extended beyond four weeks the typical microbiological, pathological and clinical features might have appeared. The occurrence of unplanned shunt infections in control animals due to canine normal skin flora reflects human clinical experience and underlines the usual source of bacteria causing shunt infection.
对分流感染的机制和发展进行详细的人体实时研究是不可能的，因此我们开发了一种犬脑积水模型来克服这一问题。这项初步研究的目的是表明，犬脑积水模型可以使用传统的“人类”分流器进行分流，并且可以建立分流感染，以便随后能够规划进一步的研究。
通过阻塞第四脑室在7只犬（家犬）中诱发脑积水。4周后，使用哈基姆精密瓣膜对它们进行分流。其中4只犬接受的分流器的脑室导管已接种表皮葡萄球菌，另外3只为未接种的对照犬。分流4周后，对犬实施安乐死并进行尸检。对取出的分流器和组织样本进行微生物学检查，并对分离株进行详细鉴定和基因组比较。
所有犬在分流后状况良好。对取出的分流器组件进行检查发现，在4只接种动物的大脑和整个分流系统中均存在表皮葡萄球菌，但其中2只还发现了中间葡萄球菌。在所有3只“阴性”对照犬中也分离出了中间葡萄球菌。中间葡萄球菌菌株之间存在细微差异，提示为内源性感染而非来自单一污染源的交叉感染。
在犬模型中建立了分流感染，如果实验延长至4周以上，可能会出现典型的微生物学、病理学和临床特征。对照动物因犬正常皮肤菌群而意外发生分流感染，这反映了人类临床经验，并突出了导致分流感染的细菌的常见来源。
