Epidemiology of Rhodococcus equi strains on thoroughbred horse farms
Epidemiology of Rhodococcus equi strains on thoroughbred horse farms
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DOI：
10.1128/aem.67.5.2167-2175.2001
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发表时间：
2001-05-01
影响因子：
4.4
通讯作者：
Browning, GF
中科院分区：
文献类型：
--
作者：
Morton, AC;Begg, AP;Browning, GF
脉冲场凝胶电泳的限制性内切核酸酶消化的基因组DNA从一个大的收集临床分离的马红球菌，一个重要的病原体的马驹，被用来比较菌株分布之间的农场和随着时间的推移。在209株分离株中发现44株，其中5株占50%以上，22株为一次以上分离株，占90%。每个农场和每年的平均基因型多样性被认为是小于作为一个整体的分离株的基因型多样性，与5.2%的总多样性是由于农场之间的差异和5.5%的差异年。每个农场的少数菌株被发现至少引起了一半的临床病例，这些病例在农场之间存在差异，在较小程度上，年份之间也存在差异。大多数菌株在一个以上的农场被发现，并且在来自不同大陆的分离株中发现了一些非常相似的限制性酶切图谱，这表明菌株可以非常广泛地传播。在6个病例中的5个病例中分离出多个菌株，其中检查了来自单个马驹的一个以上分离株，表明疾病通常可能是由多个菌株同时感染引起的。得出的结论是，存在许多携带vapA基因的马红球菌不同菌株，这些菌株往往分布广泛，但个别农场往往具有与它们相关的特定菌株。
Pulsed-field gel electrophoresis of restriction endonuclease-digested genomic DNA from a large collection of clinical isolates of Rhodococcus equi, an important pathogen of foals, was used to compare strain distribution between farms and over time. Forty-four strains were found among 209 isolates, with 5 of these accounting for over half the isolates and the 22 strains isolated more than once accounting for 90% of the isolates. The average genotypic diversity on each farm and in each year was found to be less than the genotypic diversity of the isolates taken as a whole, with 5.2% of the total diversity being due to differences between farms and 5.5% to differences between years. A small number of strains on each farm were found to have caused at least half the clinical cases of disease, and these varied between farms and, to a lesser extent, years. Most strains were found on more than one farm, and some very similar restriction patterns were found among isolates from different continents, indicating that strains can be very widespread. Multiple strains were isolated in five of the six cases in which more than one isolate from a single foal was examined, indicating that disease may commonly be caused by simultaneous infection with multiple strains, It was concluded that there are a number of different strains of R, Equi which carry the vapA gene, and these strains tend to be widespread, but individual farms tend to have particular strains associated with them.