猪链球菌病病原的致病机制研究进展

Research progress in the pathogenic mechanism of porcine streptococcosis

摘要

猪链球菌病主要由猪链球菌(Streptococcus suis, SS)和马链球菌兽疫亚种(Streptococcus equi subspecies zooepidemicus, SEZ)感染引起，是一种重要的人兽共患病。发病猪以脑膜炎、败血症、肺炎和关节炎为主要特征。人可通过接触病猪或污染产品等途径感染，引起脑膜脑炎、人链球菌样中毒性休克综合征等病症。目前，我国和东南亚等的养猪地区，SS是猪链球菌病的主要病原，血清2(SS2)、7、9、1型等血清型感染最为常见，以SS2毒力最强；由SEZ引起的猪链球菌病在北美的养猪地区被频繁报道。本文围绕定殖、突破屏障、免疫逃避、扩散及组织损伤等病原菌致病环节，介绍SS2、SEZ主要的相关研究进展，重点包括荚膜、溶血素、脂磷壁酸、自溶素、脑侵袭因子A蛋白、甘露糖特异性磷酸转移酶系统IIC组分和外泌体等关键毒力因子的生物学功能，以及丝氨酸/苏氨酸蛋白激酶、二元调控系统等磷酸化修饰系统的毒力调控作用及机制。最后，对猪链球菌病未来的研究方向进行了展望，以期为全球“减抗、限抗、禁抗”养殖新背景下该病防控新策略的探索提供参考。

Abstract

Porcine streptococcosis is primarily caused by Streptococcus suis (SS) and Streptococcus equi subspecies zooepidemicus (SEZ), which is an important zoonotic disease. Affected pigs are characterized by meningitis, septicemia, pneumonia, and arthritis. Humans can be infected through contact with diseased pigs or contaminated products, leading to meningoencephalitis and streptococcal toxic shock-like syndrome. Currently, SS is the predominant pathogen of porcine streptococcosis in China and other Southeast Asian pig-farming countries with serotype 2, 7, 9, and 1 being the most frequently detected serotypes, and serotype 2 (SS2) isolates exhibit the highest virulence. In contrast, this disease caused by SEZ in North America is frequently reported. This review summarized key research advances on SS2 and SEZ with respect to critical pathogenic processes, including colonization, barrier breakthrough, immune evasion, dissemination, and tissue damage. Emphasis is placed on the biological functions of key virulence factors such as capsule, hemolysin, lipoteichoic acid, autolysin, brain invasion factor A, PTS system mannose-specific transporter subunit IIC, and exosomes, as well as the virulence-regulatory roles of phosphorylation systems including the serine/threonine protein kinase Stk1 and two-component regulatory systems. Furthermore, the contribution of co-infections with other pathogenic microorganisms to the pathogenesis of porcine streptococcosis is discussed. Finally, future research directions are proposed, aiming to provide a reference for the development of novel prevention and control strategies under the global background of antibiotic reduction, restriction, and prohibition in animal farming.

关键词

猪链球菌病 / 致病机制 / 屏障损伤 / 免疫逃逸 / 毒力因子

Key words

porcine streptococcosis / pathogenic mechanism / barrier disruption / immune evasion / virulence factor

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基金资助

国家重点研发计划项目(2021YFD1800400)

国家自然科学基金项目(32373018)

中国科协青年人才托举工程博士生专项计划项目(156-O-230-0000197-9)

江苏省农业科技自主创新资金项目(CX(23)1029)

江苏高校优势学科建设工程专项资金项目(PAPD)