Mørk T, Jørgensen H J, Sunde M, Kvitle B, Sviland S, Waage S, Tollersrud T
Norwegian Veterinary Institute, Oslo, Norway.
Vet Microbiol. 2012 Sep 14;159(1-2):171-80. doi: 10.1016/j.vetmic.2012.03.034. Epub 2012 Mar 30.
Staphylococci are a major cause of intramammary infections (IMI) in ruminants. The main aim of this study was to investigate staphylococcal IMI in dairy cattle with emphasis on persistence and distribution of staphylococcal species and genotypes. With a sampling interval of 4-8 weeks, over a year, 4030 samples from 206 cows in 4 herds were collected. Coagulase-negative staphylococci (CNS) and Staphylococcus aureus were detected in 13.2% and 4.2% of the samples, respectively. Selected CNS isolates from quarter milk samples were identified to species level using sodA sequencing. Staphylococcus chromogenes (32%) and Staphylococcus simulans (25%) predominated. The proportion of S. chromogenes was greater in primiparous (52%) than in multiparous cows (12%), while the opposite was the case for Staphylococcus epidermidis (6% and 21%, respectively). Isolates from possibly persistent IMI were selected for pulsed-field gel electrophoresis (PFGE). Six staphylococcal species were found to cause persistent IMI; S. aureus, S. chromogenes, S. simulans, S. epidermidis, Staphylococcus haemolyticus and Staphylococcus warneri. It was shown that several pulsotypes (PTs) within each species were associated with persistent infections, but only a few were spread and caused persistent IMI in multiple cows within a herd. Of special interest was the observation that only one, or a few, strains of each species caused persistent IMI in multiple cows within a same herd. This indicates strain differences with respect to transmissibility and pathogenicity.
葡萄球菌是反刍动物乳房内感染（IMI）的主要病因。本研究的主要目的是调查奶牛的葡萄球菌性IMI，重点是葡萄球菌种类和基因型的持续性及分布情况。在一年时间里，以4 - 8周的采样间隔，从4个牛群的206头奶牛中采集了4030份样本。分别在13.2%和4.2%的样本中检测到凝固酶阴性葡萄球菌（CNS）和金黄色葡萄球菌。使用sodA测序将从四分位乳样中选取的CNS分离株鉴定到种水平。产色葡萄球菌（32%）和模仿葡萄球菌（25%）占主导。产色葡萄球菌在初产奶牛（52%）中的比例高于经产奶牛（12%），而表皮葡萄球菌的情况则相反（分别为6%和21%）。从可能持续存在的IMI中分离出的菌株用于脉冲场凝胶电泳（PFGE）分析。发现有6种葡萄球菌可导致持续性IMI；金黄色葡萄球菌、产色葡萄球菌、模仿葡萄球菌、表皮葡萄球菌、溶血葡萄球菌和沃氏葡萄球菌。结果表明，每个菌种内的几种脉冲型（PTs）与持续性感染有关，但只有少数在一个牛群中的多头发病奶牛中传播并导致持续性IMI。特别值得关注的是，观察到每个菌种只有一株或少数几株在同一牛群的多头发病奶牛中导致持续性IMI。这表明菌株在传播性和致病性方面存在差异。
