Groupe de Recherche Sur Les Maladies Infectieuses en Production Animale (GREMIP), Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte, Saint-Hyacinthe, QC, J2S 2M2, Canada.
UAB, CReSA (IRTA-UAB), Campus de la UAB, 08193, Bellaterra (Cerdanyola del Vallès), Spain.
Vet Res. 2021 Mar 20;52(1):49. doi: 10.1186/s13567-021-00918-w.
Streptococcus suis is one of the most important bacterial swine pathogens affecting post-weaned piglets, causing mainly meningitis, arthritis and sudden death. It not only results in severe economic losses but also raises concerns over animal welfare and antimicrobial resistance and remains an important zoonotic agent in some countries. The definition and diagnosis of S. suis-associated diseases can be complex. Should S. suis be considered a primary or secondary pathogen? The situation is further complicated when referring to respiratory disease, since the pathogen has historically been considered as a secondary pathogen within the porcine respiratory disease complex (PRDC). Is S. suis a respiratory or strictly systemic pathogen? S. suis is a normal inhabitant of the upper respiratory tract, and the presence of potentially virulent strains alone does not guarantee the appearance of clinical signs. Within this unclear context, it has been largely proposed that co-infection with some viral and bacterial pathogens can significantly influence the severity of S. suis-associated diseases and may be the key to understanding how the infection behaves in the field. In this review, we critically addressed studies reporting an epidemiological link (mixed infections or presence of more than one pathogen at the same time), as well as in vitro and in vivo studies of co-infection of S. suis with other pathogens and discussed their limitations and possibilities for improvement and proposed recommendations for future studies.
猪链球菌是影响断奶仔猪的最重要的细菌性猪病病原体之一，主要引起脑膜炎、关节炎和突然死亡。它不仅导致严重的经济损失，还引起了人们对动物福利和抗生素耐药性的关注，并且在一些国家仍然是一种重要的人畜共患病原体。与猪链球菌相关疾病的定义和诊断可能很复杂。猪链球菌应该被视为主要病原体还是次要病原体？当涉及到呼吸道疾病时，情况会更加复杂，因为该病原体在历史上一直被认为是猪呼吸道疾病复合症（PRDC）中的次要病原体。猪链球菌是呼吸道病原体还是严格的系统性病原体？猪链球菌是上呼吸道的正常寄居菌，仅存在潜在的毒力菌株并不能保证出现临床症状。在这种不明确的情况下，人们提出了大量观点，即与某些病毒和细菌病原体的共同感染会显著影响与猪链球菌相关疾病的严重程度，并且可能是了解感染在现场表现的关键。在这篇综述中，我们批判性地讨论了报告流行病学关联（混合感染或同时存在两种以上病原体）的研究，以及猪链球菌与其他病原体共同感染的体外和体内研究，并讨论了它们的局限性和改进的可能性，并提出了未来研究的建议。
