Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA.
Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada.
J Clin Microbiol. 2019 Aug 26;57(9). doi: 10.1128/JCM.00377-19. Print 2019 Sep.
is a significant cause of mortality in piglets and growing pigs worldwide. The species contains pathogenic and commensal strains, with pathogenic strains causing meningitis, arthritis, endocarditis, polyserositis, and septicemia. Serotyping and multilocus sequence typing (MLST) are primary methods to differentiate strains, but the information is limited for strains found in the United States. The objective of this study was to characterize the diversity of 208 isolates collected between 2014 and 2017 across North America (mainly the United States) by serotyping and MLST and to investigate associations between subtype and pathotype classifications (pathogenic, possibly opportunistic, and commensal), based on clinical information and site of isolation. Twenty serotypes were identified, and the predominant serotypes were 1/2 and 7. Fifty-eight sequence types (STs) were identified, and the predominant ST was ST28. Associations among serotypes, STs, and pathotypes were investigated using odds ratio and clustering analyses. Evaluation of serotype and ST with pathotype identified a majority of isolates of serotypes 1, 1/2, 2, 7, 14, and 23 and ST1, ST13, ST25, ST28, ST29, ST94, ST108, ST117, ST225, ST373, ST961, and ST977 as associated with the pathogenic pathotype. Serotypes 21 and 31, ST750, and ST821 were associated with the commensal pathotype, which is composed of isolates from farms with no known history of -associated disease. Our study demonstrates the use of serotyping and MLST to differentiate pathogenic from commensal isolates and establish links between pathotype and subtype, thus increasing the knowledge about strains circulating in the United States.
是全球仔猪和生长猪死亡的重要原因。该物种包含病原和共生菌株，病原菌株可引起脑膜炎、关节炎、心内膜炎、多发性浆膜炎和败血症。血清分型和多位点序列分型（MLST）是区分菌株的主要方法，但针对美国发现的菌株，相关信息有限。本研究的目的是通过血清分型和 MLST 对 2014 年至 2017 年间在北美（主要是美国）收集的 208 株分离株的多样性进行特征描述，并根据临床信息和分离部位，调查亚型和病原型分类（病原型、可能机会性和共生型）之间的关联。鉴定出 20 种血清型，主要血清型为 1/2 和 7。鉴定出 58 种序列型（ST），主要 ST 为 ST28。使用比值比和聚类分析研究血清型、ST 和病原型之间的关联。使用血清型和 ST 评估病原型确定了大多数血清型 1、1/2、2、7、14 和 23 以及 ST1、ST13、ST25、ST28、ST29、ST94、ST108、ST117、ST225、ST373、ST961 和 ST977 的分离株与病原型相关。血清型 21 和 31、ST750 和 ST821 与共生型相关，共生型由来自无已知相关疾病史的农场的分离株组成。本研究表明，血清分型和 MLST 可用于区分病原和共生分离株，并建立病原型与亚型之间的联系，从而增加对美国流行菌株的了解。
