Comparative molecular analysis of ovine and bovine Streptococcus uberis isolates
Comparative molecular analysis of ovine and bovine Streptococcus uberis isolates
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DOI：
10.3168/jds.2012-5705
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发表时间：
2013-02-01
影响因子：
3.5
通讯作者：
Fontaine, M. C.
中科院分区：
文献类型：
--
作者：
Gilchrist, T. L.;Smith, D. G. E.;Fontaine, M. C.
链球菌引起牛和羊的临床和亚临床乳腺炎，但尚不清楚链球菌的组成。不同宿主物种之间的寄生虫种群不同。为了解决这个问题，我们表征了牛和羊链球菌的集合。通过扩展的多位点序列分型方案，对具有共同地理和时间起源的分离株进行了鉴定。在14个绵羊和35个牛分离株中，检测到35个等位基因谱。每个等位基因配置文件与一个单一的主机种，但所有的多位点序列分型数据库是新的。绵羊分离株的新等位基因中位数高于牛分离株。没有绵羊分离株属于全球克隆复合体5或143，这是通常与牛乳腺炎，并具有广泛的地理分布。绵羊分离株在纤溶酶原激活剂基因的携带方面也与牛分离株不同，绵羊分离株中pauB的患病率显着更高。在绵羊和牛分离株中发现了对yqiL（多位点序列分型的目标之一）呈阴性的分离株，并且与特定序列类型或全局克隆复合体无关。一个牛分离株携带gapC等位基因，可能是通过横向基因转移获得的，最有可能来自唾液链球菌。我们得出结论，绵羊分离株是不同的牛链球菌。来自不同宿主种属或细菌种属的分离株之间的重组可能导致与疫苗开发相关的毒力基因谱的变化。
Streptococcus uberis causes clinical and subclinical mastitis in cattle and sheep, but it is unknown whether the composition of Strep. uberis populations differs between host species. To address this, we characterized a collection of bovine and ovine Strep. uberis isolates with shared geographical and temporal origins by means of an expanded multilocus sequence typing scheme. Among 14 ovine and 35 bovine isolates, 35 allelic profiles were detected. Each allelic profile was associated with a single host species and all but one were new to the multilocus sequence typing database. The median number of new alleles per isolate was higher for ovine isolates than for bovine isolates. None of the ovine isolates belonged to the global clonal complexes 5 or 143, which are commonly associated with bovine mastitis and which have a wide geographical distribution. Ovine isolates also differed from bovine isolates in carriage of plasminogen activator genes, with significantly higher prevalence of pauB in ovine isolates. Isolates that were negative for yqiL, one of the targets of multilocus sequence typing, were found among ovine and bovine isolates and were not associated with a specific sequence type or global clonal complex. One bovine isolate carried a gapC allele that was probably acquired through lateral gene transfer, most likely from Streptococcus salivarius. We conclude that ovine isolates are distinct from bovine isolates of Strep. uberis, and that recombination between isolates from different host species or bacterial species could contribute to changes in virulence gene profiles with relevance for vaccine development.