Bender J S, Shen H G, Irwin C K, Schwartz K J, Opriessnig T
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Clin Vaccine Immunol. 2010 Oct;17(10):1605-11. doi: 10.1128/CVI.00206-10. Epub 2010 Aug 18.
The aim of this study was to characterize Erysipelothrix sp. isolates from clinically affected pigs and their environment and compare them to the Erysipelothrix sp. vaccines used at the sites. Samples were collected during swine erysipelas outbreaks in vaccinated pigs in six Midwest United States swine operations from 2007 to 2009. Pig tissue samples were collected from 1 to 3 pigs from each site. Environmental samples (manure, feed, central-line water, oral fluids, and swabs collected from walls, feed lines, air inlets, exhaust fans, and nipple drinkers) and live vaccine samples were collected following the isolation of Erysipelothrix spp. from clinically affected pigs. All Erysipelothrix sp. isolates obtained were further characterized by serotyping. Selected isolates were further characterized by PCR assays for genotype (E. rhusiopathiae, E. tonsillarum, Erysipelothrix sp. strain 1, and Erysipelothrix sp. strain 2) and surface protective antigen (spa) type (A, B1, B2, and C). All 26 isolates obtained from affected pigs were E. rhusiopathiae, specifically, serotypes 1a, 1b, 2, and 21. From environmental samples, 56 isolates were obtained and 52/56 were E. rhusiopathiae (serotypes 1a, 1b, 2, 6, 9, 12, and 21), 3/56 were Erysipelothrix sp. strain 1 (serotypes 13 and untypeable), and one was a novel species designated Erysipelothrix sp. strain 3 (serotype untypeable). Four of six vaccines used at the sites were commercially available products and contained live E. rhusiopathiae serotype 1a. Of the remaining two vaccines, one was an autogenous live vaccine and contained live E. rhusiopathiae serotype 2 and one was a commercially produced inactivated vaccine and was described by the manufacturer to contain serotype 2 antigen. All E. rhusiopathiae isolates were positive for spaA. All Erysipelothrix sp. strain 1 isolates and the novel Erysipelothrix sp. strain 3 isolate were negative for all currently known spa types (A, B1, B2, and C). These results indicate that Erysipelothrix spp. can be isolated from the environment of clinically affected pigs; however, the identified serotypes in pigs differ from those in the environment at the selected sites. At one of the six affected sites, the vaccine strain and the isolates from clinically affected pigs were of homologous serotype; however, vaccinal and clinical isolates were of heterologous serotype at the remaining five sites, suggesting that reevaluation of vaccine efficacy using recent field strains may be warranted.
本研究的目的是对从临床发病猪及其环境中分离出的丹毒丝菌属菌株进行特征分析，并将其与这些猪场使用的丹毒丝菌属疫苗进行比较。2007年至2009年期间，在美国中西部六个养猪场中，对接种疫苗后发生猪丹毒疫情的猪群进行了样本采集。从每个猪场的1至3头猪身上采集猪组织样本。在从临床发病猪中分离出丹毒丝菌属菌株后，采集环境样本（粪便、饲料、中央供水、口腔分泌物，以及从墙壁、饲料管道、进气口、排气扇和乳头饮水器采集的拭子）和活疫苗样本。对所有获得的丹毒丝菌属菌株进行血清分型，以进一步鉴定其特征。对选定的菌株通过PCR检测进行基因型（猪红斑丹毒丝菌、扁桃体丹毒丝菌、丹毒丝菌属菌株1和丹毒丝菌属菌株2）和表面保护性抗原（spa）类型（A、B1、B2和C）的进一步鉴定。从发病猪中获得的所有26株菌株均为猪红斑丹毒丝菌，具体血清型为1a、1b、2和21。从环境样本中获得了56株菌株，其中52/56为猪红斑丹毒丝菌（血清型1a、1b、2、6、9、12和21），3/56为丹毒丝菌属菌株1（血清型13和无法分型），1株为新物种，命名为丹毒丝菌属菌株3（血清型无法分型）。这些猪场使用的六种疫苗中有四种是市售产品，含有活的猪红斑丹毒丝菌血清型1a。其余两种疫苗中，一种是自体活疫苗，含有活的猪红斑丹毒丝菌血清型2，另一种是市售灭活疫苗，生产商称其含有血清型2抗原。所有猪红斑丹毒丝菌菌株的spaA均呈阳性。所有丹毒丝菌属菌株1和新的丹毒丝菌属菌株3对目前已知的所有spa类型（A、B1、B2和C）均呈阴性。这些结果表明，可以从临床发病猪的环境中分离出丹毒丝菌属菌株；然而，在选定猪场中，猪身上鉴定出的血清型与环境中的不同。在六个发病猪场中的一个，疫苗菌株与临床发病猪分离出的菌株血清型相同；然而，在其余五个猪场中，疫苗株与临床分离株血清型不同，这表明可能有必要使用近期的田间菌株重新评估疫苗效力。
