Silva E, Gaivão M, Leitão S, Jost B H, Carneiro C, Vilela C L, Lopes da Costa L, Mateus L
Department of Reproduction and Obstetrics, C.I.I.S.A., Faculty of Veterinary Medicine, Avenida Universidade Técnica, Alto da Ajuda, Polo Universitário, 1300-477 Lisbon, Portugal.
Vet Microbiol. 2008 Nov 25;132(1-2):111-8. doi: 10.1016/j.vetmic.2008.04.033. Epub 2008 May 2.
Arcanobacterium pyogenes is considered to be the most relevant bacterium involved in the establishment of puerperal uterine infection in cattle due to its persistence in utero, resistance to treatment and synergic action with Gram negative anaerobes. Once the infection is established, A. pyogenes is responsible for the persistence of the infection. The objective of this study was to characterize A. pyogenes field isolates recovered from the uterus of cows with either normal puerperium or clinical metritis, in an attempt to identify factors that might be associated with the establishment and persistence of the disease. This characterization was based on BOX-PCR typing and on screening of eight virulence factor genes (plo, nanP, nanH, cbpA, fimA, fimC, fimE, fimG) by conventional PCR. Finally, a relationship between clonal types, virulence factors and presence of disease was investigated. A. pyogenes clonal types identified from isolates recovered from the uterus of postpartum dairy cows differed among herds. Although some clonal types were strictly associated with the development of clinical metritis, others were identified from isolates recovered from normal puerperium and clinical metritis cows. Moreover, the presence of the eight virulence factor genes was not related with the ability to induce clinical metritis, suggesting that the type of A. pyogenes may not be a determinant factor in the development of the disease. We suggest that host intrinsic factors, the synergism between A. pyogenes and other bacteria and the differential gene expression of virulence factor genes may play a more relevant role in the establishment of puerperal uterine infections.
化脓隐秘杆菌被认为是导致奶牛产后子宫感染的最主要相关细菌，因为它能在子宫内持续存在、对治疗有抗性，且能与革兰氏阴性厌氧菌产生协同作用。一旦感染确立，化脓隐秘杆菌就会导致感染持续存在。本研究的目的是对从正常产褥期或临床型子宫内膜炎奶牛子宫中分离出的化脓隐秘杆菌田间分离株进行特征分析，以试图确定可能与该病的发生和持续存在相关的因素。这种特征分析基于BOX-PCR分型以及通过常规PCR对八个毒力因子基因（plo、nanP、nanH、cbpA、fimA、fimC、fimE、fimG）进行筛选。最后，研究了克隆类型、毒力因子与疾病存在之间的关系。从产后奶牛子宫分离出的化脓隐秘杆菌克隆类型在不同牛群中存在差异。虽然一些克隆类型与临床型子宫内膜炎的发生密切相关，但其他克隆类型也从正常产褥期和临床型子宫内膜炎奶牛的分离株中鉴定出来。此外，八个毒力因子基因的存在与诱导临床型子宫内膜炎的能力无关，这表明化脓隐秘杆菌的类型可能不是该病发生的决定性因素。我们认为宿主内在因素、化脓隐秘杆菌与其他细菌之间的协同作用以及毒力因子基因的差异表达可能在产后子宫感染的发生中起更重要的作用。
