Hampson David J, La Tom, Phillips Nyree D
School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6112 Australia.
Porcine Health Manag. 2015 Jun 12;1:8. doi: 10.1186/s40813-015-0002-1. eCollection 2015.
This short review discusses the increasing complexity that has developed around the understanding of species that infect pigs, and their ability to cause disease. It describes the recognition of new weakly haemolytic species, and the growing appreciation that and some other weakly haemolytic species may be pathogenic in pigs. It discusses swine dysentery (SD) caused by the strongly haemolytic , particularly the cyclical nature of the disease whereby it can largely disappear as a clinical problem from a farm or region, and re-emerge years later. The review then describes the recent emergence of two newly described strongly haemolytic pathogenic species, "" and "" both of which appear to have reservoirs in migratory waterbirds, and which may be transmitted to and between pigs. "" seems to be confined to Scandinavia, whereas "" has been reported in North America and Europe, causes a disease indistinguishable from SD, and has required the development of new routine diagnostic tests. Besides the emergence of new species, strains of known species have emerged that vary in important biological properties, including antimicrobial susceptibility and virulence. Strains can be tracked locally and at the national and international levels by identifying them using multilocus sequence typing (MLST) and comparing them against sequence data for strains in the PubMLST databases. Using MLST in conjunction with data on antimicrobial susceptibility can form the basis for surveillance programs to track the movement of resistant clones. In addition some strains of have low virulence potential, and some of these have been found to lack the 36 kB plasmid or certain genes on the plasmid whose activity may be associated with colonization. Lack of the plasmid or the genes can be identified using PCR testing, and this information can be added to the MLST and resistance data to undertake detailed surveillance. Strains of low virulence are particularly important where they occur in high health status breeding herds without causing obvious disease: potentially they could be transmitted to production herds where they may colonize more effectively and cause disease under stressful commercial conditions.
这篇简短的综述讨论了在理解感染猪的病原体及其致病能力方面日益增加的复杂性。它描述了新的弱溶血性病原体的发现，以及对某些其他弱溶血性病原体可能对猪致病的认识不断增加。它讨论了由强溶血性病原体引起的猪痢疾（SD），特别是该病的周期性，即它可能在很大程度上从一个农场或地区作为临床问题消失，多年后又重新出现。综述接着描述了最近出现的两种新描述的强溶血性病原体“”和“”，它们似乎在迁徙水鸟中有储存宿主，并且可能在猪之间传播。“”似乎局限于斯堪的纳维亚半岛，而“”已在北美和欧洲被报道，引起与SD难以区分的疾病，并且需要开发新的常规诊断测试。除了新病原体的出现，已知病原体的菌株也出现了，其重要生物学特性存在差异，包括抗菌药物敏感性和毒力。通过使用多位点序列分型（MLST）对菌株进行鉴定并与PubMLST数据库中的菌株序列数据进行比较，可以在本地、国家和国际层面追踪菌株。将MLST与抗菌药物敏感性数据结合使用可为监测耐药克隆的传播提供基础。此外，某些菌株的毒力潜力较低，其中一些已被发现缺乏36 kB质粒或该质粒上某些可能与定植相关的基因。可以使用PCR检测来鉴定是否缺乏质粒或基因，并且可以将此信息添加到MLST和耐药性数据中以进行详细监测。低毒力菌株在高健康状态的繁殖猪群中出现但不引起明显疾病的情况下尤为重要：它们有可能传播到生产猪群中，在商业压力条件下可能更有效地定植并引起疾病。
