Infection mechanism of biofilm-forming Staphylococcus aureus on indwelling foreign materials in mice
Infection mechanism of biofilm-forming Staphylococcus aureus on indwelling foreign materials in mice
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DOI：
10.1111/iwj.12061
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发表时间：
2015-04-01
影响因子：
3.1
通讯作者：
Ohjimi, Hiroyuki
中科院分区：
文献类型：
--
作者：
Makino, Taro;Jimi, Shiro;Ohjimi, Hiroyuki
留置异物感染是一个严重的医疗问题，特别是在免疫功能低下的患者。为了检测附着在异物上的生物膜形成细菌的致病性，植入塑料圆盘的小鼠感染金黄色葡萄球菌。在伴有或不伴有暂时性白细胞减少症的小鼠背侧打开一个较宽的皮下袋后，将塑料片置于左侧皮下空间中;随后，将处于无菌状态的细菌分散在皮下空间中。接种后7 d进行细菌计数。在右侧皮下组织中，S。金黄色葡萄球菌仅在白细胞减少的小鼠中发现。同时，在白细胞减少症小鼠和正常小鼠的塑料和邻近组织上检测到细菌;然而，菌落形成分析表明，白细胞减少症小鼠具有显著更多的细菌。病理学检查组织对细菌的反应。入侵S.金黄色葡萄球菌引起严重炎症。在短暂性白细胞减少的小鼠中，在塑料上以及在发育的坏死组织中形成的细菌小菌落-两者都被保护免受炎性细胞浸润-导致菌血症。这些结果表明，生物膜形成S。金黄色葡萄球菌附着在留置异物上，耐受宿主免疫力并攻击邻近组织，这可能导致慢性伤口感染。
Indwelling foreign-body infections are a critical medical problem, especially in immunocompromised patients. To examine the pathogenicity of biofilm-forming bacteria settling on foreign materials, mice implanted with plastic discs were infected with Staphylococcus aureus. After opening a wide subcutaneous pocket on the dorsal side of mice with or without temporal leukocytopenia, a plastic sheet was placed in the left subcutaneous space; subsequently, bacteria in a planktonic state were dispersed over the subcutaneous space. Bacterial numbers were examined 7days after inoculation. In subcutaneous tissue on the right, S. aureus was found only in leukocytopenic mice. Meanwhile, bacteria were detected on the plastic and neighbouring tissue in both leukocytopenic and normal mice; however, colony-forming analysis indicated that leukocytopenic mice possessed significantly more bacteria. Tissue reaction against bacteria was pathologically examined. Invading S. aureus induced severe inflammation. In transient leukocytopenic mice, bacterial microcolonies formed on the plastic as well as in the developed necrotic tissue - both of which were shielded from inflammatory cell infiltration - result in bacteraemia. These results indicate that biofilm-forming S. aureus settling on indwelling foreign material are tolerant against host immunity and assault neighbouring tissue, which may lead to chronic wound infection.