Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
Vet Microbiol. 2012 Feb 24;155(1):62-71. doi: 10.1016/j.vetmic.2011.08.005. Epub 2011 Aug 9.
Although many studies report coagulase-negative staphylococci (CNS) as the predominant cause of subclinical bovine mastitis, their epidemiology is poorly understood. In the current study, the genetic diversity within four CNS species frequently associated with bovine intramammary infections, Staphylococcus haemolyticus, S. simulans, S. chromogenes, and S. epidermidis, was determined. For epidemiological purposes, CNS genotypes recovered from bovine milk collected on six Flemish dairy farms were compared with those from the farm environment, and their distribution within the farms was investigated. Genetic diversity was assessed by two molecular typing techniques, amplification fragment length polymorphism (AFLP) and random amplification of polymorphic DNA (RAPD) analysis. Subtyping revealed the highest genetic heterogeneity among S. haemolyticus isolates. A large variety of genotypes was found among environmental isolates, of which several could be linked with intramammary infection, indicating that the environment could act as a potential source for infection. For S. simulans, various genotypes were found in the environment, but a link with IMI was less obvious. For S. epidermidis and S. chromogenes, genetic heterogeneity was limited and the sporadic isolates from environment displayed largely the same genotypes as those from milk. The higher clonality of the S. epidermidis and S. chromogenes isolates from milk suggests that specific genotypes probably disseminate within herds and are more udder-adapted. Environmental sources and cow-to-cow transmission both seem to be involved in the epidemiology of CNS, although their relative importance might substantially vary between species.
虽然许多研究报告称凝固酶阴性葡萄球菌（CNS）是亚临床牛乳腺炎的主要原因，但它们的流行病学仍了解甚少。在本研究中，我们确定了与牛乳腺炎感染密切相关的四种 CNS 物种（解乳糖葡萄球菌、模仿葡萄球菌、中间葡萄球菌和表皮葡萄球菌）的遗传多样性。为了进行流行病学研究，我们将从六个佛兰德奶牛场采集的牛奶中回收的 CNS 基因型与来自农场环境的基因型进行了比较，并调查了它们在农场内的分布情况。遗传多样性通过两种分子分型技术（扩增片段长度多态性（AFLP）和随机扩增多态性 DNA（RAPD）分析）进行评估。亚分型显示解乳糖葡萄球菌分离株的遗传异质性最高。在环境分离株中发现了各种各样的基因型，其中一些可能与乳腺炎有关，这表明环境可能是感染的潜在来源。对于模仿葡萄球菌，在环境中发现了各种基因型，但与 IMI 的联系不太明显。对于表皮葡萄球菌和中间葡萄球菌，遗传异质性有限，环境中的散发性分离株与牛奶中的分离株显示出大致相同的基因型。来自牛奶的表皮葡萄球菌和中间葡萄球菌分离株的更高克隆性表明，特定基因型可能在畜群中传播，并且更适应于乳房。尽管 CNS 的流行病学可能涉及环境来源和牛与牛之间的传播，但它们的相对重要性可能在不同物种之间有很大差异。
