Nicholson Tracy L, Brockmeier Susan L, Sukumar Neelima, Paharik Alexandra E, Lister Jessica L, Horswill Alexander R, Kehrli Marcus E, Loving Crystal L, Shore Sarah M, Deora Rajendar
National Animal Disease Center, Agricultural Research Service, USDA, Ames, Iowa, USA
National Animal Disease Center, Agricultural Research Service, USDA, Ames, Iowa, USA.
Infect Immun. 2017 Jul 19;85(8). doi: 10.1128/IAI.00261-17. Print 2017 Aug.
is pervasive in swine populations and plays multiple roles in respiratory disease. Additionally, is capable of establishing long-term or chronic infections in swine. Bacterial biofilms are increasingly recognized as important contributors to chronic bacterial infections. Recently the polysaccharide locus has been demonstrated to serve a critical role in the development of mature biofilms formed by the sequenced laboratory strain of We hypothesized that swine isolates would also have the ability to form mature biofilms and the locus would serve a key role in this process. A mutant containing an in-frame deletion of the structural genes was constructed in a wild-type swine isolate and found to be negative for poly-N-acetylglucosamine (PNAG)-like material by immunoblot assay. Further, the locus was found to be required for the development and maintenance of the three-dimensional structures under continuous-flow conditions. To investigate the contribution of the locus to the pathogenesis of in swine, the KM22Δ mutant was compared to the wild-type swine isolate for the ability to colonize and cause disease in pigs. The locus was found to not be required for persistence in the upper respiratory tract of swine. Additionally, the locus did not affect the development of anti- humoral immunity, did not contribute to disease severity, and did not mediate protection from complement-mediated killing. However, the locus was found to enhance survival in the lower respiratory tract of swine.
在猪群中普遍存在，并在呼吸道疾病中发挥多种作用。此外，能够在猪体内建立长期或慢性感染。细菌生物膜越来越被认为是慢性细菌感染的重要促成因素。最近，多糖位点已被证明在由测序实验室菌株形成的成熟生物膜的发育中起关键作用。我们假设猪分离株也有能力形成成熟生物膜，并且该位点在此过程中将起关键作用。在野生型猪分离株中构建了一个包含该结构基因框内缺失的突变体，通过免疫印迹分析发现其聚-N-乙酰葡糖胺（PNAG）样物质呈阴性。此外，发现该位点对于在连续流动条件下三维结构的发育和维持是必需的。为了研究该位点对猪体内该菌发病机制的贡献，将KM22Δ突变体与野生型猪分离株在猪体内定殖和致病的能力进行了比较。发现该位点对于在猪的上呼吸道中持续存在不是必需的。此外，该位点不影响抗体液免疫的发展，对疾病严重程度没有影响，也不介导免受补体介导杀伤的保护作用。然而，发现该位点可提高在猪下呼吸道中的存活率。
