Acuff Nicole V, LaGatta Monica, Nagy Tamas, Watford Wendy T
Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA.
Department of Pathology, University of Georgia, Athens, Georgia, USA.
Comp Med. 2017 Aug 1;67(4):344-349.
Staphylococcus xylosus is a commensal bacterium found on the skin and mucosal surfaces of SPF mice. S. xylosus is rarely pathogenic, most often causing skin lesions and dermatitis in immunocompromised mice, particularly those with impaired NADPH oxidase function. Here we report spontaneous infection with S. xylosus in Rag1-/-Tpl2-/- mice. Infection was characterized by the presence of alopecia, crusts, and scaly skin. S. xylosus was detected in the feces, skin, lymph nodes, and lungs of Rag1-/-Tpl2-/- mice and led to mortality or euthanasia due to humane endpoints. C57BL/6 mice were culture-positive for S. xylosus on the skin, and Rag1-/- and Tpl2-/- mice were culture-positive on the skin and occasionally in the feces. However, S. xylosus did not cause clinical symptoms in C57BL/6, Rag1-/-, or Tpl2-/- mice. Compared with those in Rag1-/- mice, relative concentrations of circulating monocytes, but not neutrophils or lymphocytes, were increased in Rag1-/-Tpl2-/- mice, consistent with their increased incidence of clinical symptoms. Overall, this case study suggests a novel role for Tpl2 in T-cell-independent host resistance to the otherwise commensal organism S. xylosus.
木糖葡萄球菌是一种在无特定病原体（SPF）小鼠的皮肤和黏膜表面发现的共生细菌。木糖葡萄球菌很少致病，最常见的是在免疫功能低下的小鼠中引起皮肤病变和皮炎，尤其是那些NADPH氧化酶功能受损的小鼠。在此，我们报告了Rag1-/-Tpl2-/-小鼠中木糖葡萄球菌的自发感染情况。感染的特征是出现脱毛、结痂和皮肤鳞屑。在Rag1-/-Tpl2-/-小鼠的粪便、皮肤、淋巴结和肺中检测到了木糖葡萄球菌，并且由于人道终点导致了死亡或安乐死。C57BL/6小鼠的皮肤木糖葡萄球菌培养呈阳性，Rag1-/-和Tpl2-/-小鼠的皮肤培养呈阳性，偶尔粪便培养也呈阳性。然而，木糖葡萄球菌在C57BL/6、Rag1-/-或Tpl2-/-小鼠中并未引起临床症状。与Rag1-/-小鼠相比，Rag1-/-Tpl2-/-小鼠循环单核细胞的相对浓度升高，而中性粒细胞或淋巴细胞的浓度未升高，这与它们临床症状发生率的增加一致。总体而言，该病例研究表明Tpl2在T细胞非依赖性宿主对原本为共生菌的木糖葡萄球菌的抵抗力中具有新作用。
