Departamento de Patologia, Faculdade de Medicina, Universidade Federal Fluminense, Rio de Janeiro, Brasil.
Health Sciences Center, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
J Appl Microbiol. 2020 Jun;128(6):1820-1842. doi: 10.1111/jam.14598. Epub 2020 Feb 20.
Staphylococcus aureus is one of the most common pathogens in hospital environment and community. Panton-Valentine leukocidin (PVL) production is clinically associated with skin abscesses, soft tissues infections, bacteraemia and sepsis. This study aimed to investigate the effects of the presence of genes lukF/S-PV coding for PVL, in histological and haematological features during systemic infection, using a Swiss mice experimental model.
Experiments were performed using 25 mice distributed into five experimental groups, intravenously inoculated with 50 µl suspensions at density 1·0 × 10 CFU per ml of strains: methicillin-susceptible (MSSA) and pvl-negative strains isolated from nasal colonization; MSSA pvl-positive strains isolated from nasal colonization; methicillin-resistant (MRSA) and pvl-positive strains isolated from peripheral blood of a patient with severe pulmonary infection; and a MRSA pvl-positive strains isolated from a peripheral blood culture of a patient with bacteraemia. Haematological analysis was performed at 24, 48, 72 and 96 h post-infection. Morphoanatomy and histopathological analyses were performed at 96 h post-infection. For all S. aureus strains tested, the capability of intravenous dissemination and survival into mice tissues was demonstrated. Inflammatory processes at different levels were related to the presence of pvl genes, and included alterations in the format, size and colour of the organs. Staphylococcus aureus pvl-positive strains were detected in greater numbers in the organs of the infected animals.
The pvl-positive strains isolated from blood cultures were capable to induce the greatest modifications in both haematological and histopathological profiles, and seemed to aggravate the systemic infections.
These findings are valuable in characterizing infections caused by S. aureus in humans and murine.
金黄色葡萄球菌是医院环境和社区中最常见的病原体之一。产肠毒素金黄色葡萄球菌（PVL）的产生与皮肤脓肿、软组织感染、菌血症和败血症等临床症状有关。本研究旨在使用瑞士小鼠实验模型，研究编码 PVL 的 lukF/S-PV 基因的存在对全身感染时组织学和血液学特征的影响。
本实验使用 25 只小鼠，分为五组，每组 5 只，每组通过静脉注射 50µl 密度为 1.0×10 个 CFU/ml 的菌株悬液：从鼻腔定植分离的耐甲氧西林金黄色葡萄球菌（MSSA）和 pvl 阴性株；从鼻腔定植分离的 MSSA pvl 阳性株；从严重肺部感染患者外周血分离的耐甲氧西林金黄色葡萄球菌（MRSA）和 pvl 阳性株；从菌血症患者外周血培养分离的 MRSA pvl 阳性株。在感染后 24、48、72 和 96 小时进行血液分析。在感染后 96 小时进行形态解剖和组织病理学分析。所有测试的金黄色葡萄球菌菌株均证明了其在静脉内传播和在小鼠组织中存活的能力。不同水平的炎症过程与 pvl 基因的存在有关，包括器官形态、大小和颜色的改变。在感染动物的器官中，pvl 阳性株金黄色葡萄球菌的数量更多。
从血培养中分离的 pvl 阳性株能够引起血液学和组织病理学特征的最大改变，并似乎加重了全身感染。
这些发现对于表征金黄色葡萄球菌在人类和鼠类中的感染具有重要价值。
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