In this descriptive pilot study, we aim to establish a porcine Staphylococcus aureus skin infection model by subcutaneous injection (s.c.) of the porcine S54F9 S. aureus strain in the groin area. Six pigs were used in the study: Five pigs were injected with S. aureus, inocula ranging from 7 × 10³ to 5 × 10⁷ colony-forming units per kg bodyweight; one pig was injected with saline exclusively. Lesions were recorded up to 6 days postinoculation using clinical evaluation, ultrasound evaluation, microbiology, flow cytometry, and pathology. Inoculation gave rise to lesions ranging from localized skin infection, that is, minute histological changes, intracellular infection, and macroscopic abscess formation with sequestration of soft tissue, to generalized infection and development of disseminated intravascular coagulation necessitating euthanasia only 10 h after inoculation. Ultrasound assessment of maximum width and characteristics was not able to disclose the progress of the local infection. Flow cytometry and immunohistochemistry revealed the participation of γδT cells in the immune response. In conclusion, we did see a graded inflammatory response associated with the dose of s.c. inoculated bacteria, which may be useful for studying, in particular, the interaction of bacteria and inflammatory mononuclear cell populations. It needs to be investigated if the model is discriminatory and robust.

中文翻译：

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猪皮下金黄色葡萄球菌感染模型：初步研究

在这项描述性试验研究中，我们旨在通过在腹股沟区域皮下注射 (sc) 猪 S54F9金黄色葡萄球菌菌株来建立猪金黄色葡萄球菌皮肤感染模型。研究中使用了六头猪：五头猪注射了金黄色葡萄球菌，接种量范围为 7 × 10 ³至 5 × 10 ⁷每公斤体重的菌落形成单位；一头猪只注射生理盐水。使用临床评估、超声评估、微生物学、流式细胞术和病理学记录最多接种后 6 天的病变。接种引起的损伤范围从局部皮肤感染，即微小的组织学变化、细胞内感染和肉眼可见的脓肿形成，伴有软组织的隔离，到全身感染和播散性血管内凝血的发展，在接种后仅 10 小时就需要安乐死。最大宽度和特征的超声评估无法揭示局部感染的进展。流式细胞术和免疫组织化学揭示了γδT细胞参与免疫反应。综上所述，我们确实看到了与 sc 接种细菌剂量相关的分级炎症反应，这可能有助于研究，特别是细菌和炎症性单核细胞群的相互作用。如果模型具有区分性和鲁棒性，则需要对其进行调查。