Zhang Jack, Conly John, McClure JoAnn, Wu Kaiyu, Petri Bjӧrn, Barber Duane, Elsayed Sameer, Armstrong Glen, Zhang Kunyan
Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB T2N4N1, Canada.
Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB T2N4N1, Canada.
Microorganisms. 2021 Jan 30;9(2):287. doi: 10.3390/microorganisms9020287.
USA300 is a predominant and highly virulent community-associated methicillin-resistant (CA-MRSA) strain that is a leading cause of skin and soft tissue infections. We established a murine intradermal infection model capable of demonstrating dermatopathological differences between USA300 and other MRSA strains. In this model, USA300 induced dermonecrosis, uniformly presenting as extensive open lesions with a histologically documented profound inflammatory cell infiltrate extending below the subcutis. In contrast, USA400 and a colonizing control strain M92 caused only localized non-ulcerated skin infections associated with a mild focal inflammatory infiltrate. It was also determined that the dermonecrosis induced by USA300 was associated with significantly increased neutrophil recruitment, inhibition of an antibacterial response, and increased production of cytokines/chemokines associated with disease severity. These results suggest that induction of severe skin lesions by USA300 is related to over-activation of neutrophils, inhibition of host antibacterial responses, and selective alteration of host cytokine/chemokine profiles.
USA300是一种占主导地位且毒性很强的社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）菌株，是皮肤和软组织感染的主要病因。我们建立了一种小鼠皮内感染模型，该模型能够显示USA300与其他MRSA菌株之间的皮肤病理差异。在这个模型中，USA300诱导皮肤坏死，均表现为广泛的开放性病变，组织学记录显示有大量炎性细胞浸润延伸至皮下组织以下。相比之下，USA400和定殖对照菌株M92仅引起局部非溃疡性皮肤感染，并伴有轻度局灶性炎性浸润。研究还确定，USA300诱导的皮肤坏死与中性粒细胞募集显著增加、抗菌反应受到抑制以及与疾病严重程度相关的细胞因子/趋化因子产生增加有关。这些结果表明，USA300诱导严重皮肤病变与中性粒细胞过度活化、宿主抗菌反应受到抑制以及宿主细胞因子/趋化因子谱的选择性改变有关。
