Difference in virulence between Staphylococcus aureus isolates causing gangrenous mastitis versus subclinical mastitis in a dairy sheep flock
Difference in virulence between Staphylococcus aureus isolates causing gangrenous mastitis versus subclinical mastitis in a dairy sheep flock
复制标题
奶羊群中引起坏疽性乳腺炎与亚临床乳腺炎的金黄色葡萄球菌分离株的毒力差异
作者：
E. Vautor;Joshua D Cockfield;Caroline Le Marechal;Y. Le Loir;M. Chevalier;D. A. Robinson;R. Thiery;J. Lindsay
金黄色葡萄球菌乳腺炎的范围从亚临床型乳腺炎到致死性坏疽性乳腺炎。也不是S。金黄色葡萄球菌毒力因子、宿主因子或导致不同结果的流行病学事件都是已知的。在一个奶牛场进行了为期21个月的田间研究，16个自然分离的沙门氏菌。金黄色葡萄球菌是从六个隐性乳房炎病例、一个致死性坏疽性乳房炎病例、八只母羊的鼻携带物和一个来自挤奶室环境空气的分离物中收集的。使用多菌株DNA微阵列对两种菌株进行基因组比较，一种负责亚临床型乳腺炎，一种负责致死性坏疽性乳腺炎。多重分型技术（脉冲场凝胶电泳，多位点可变数目，单核苷酸多态性，随机扩增多态性DNA，SPA分型和SAS分型）被用来鉴定剩余的分离株，并遵循坏疽分离株在母羊鼻孔中的持久性。结果表明，两株菌在遗传上亲缘关系较近，共有3 615个相同的开放阅读框。然而，坏疽性乳腺炎分离株携带几种基因（sdrD、clfA-B、sasA、sasB、sasD、sasI和splE）的变体，并且缺失纤维蛋白原结合蛋白B（fnb B）和原噬菌体。分型结果表明，这种坏疽菌株出现后，最初的隐性乳房炎筛选，但随后坚持在羊群中的4只母羊的鼻孔。尽管我们不能忽视宿主易感性在这一群临床事件中的作用，但我们的数据支持S.金黄色葡萄球菌种群已经在羊群中进化，S.金黄色葡萄球菌的遗传变异可能有助于增强毒力。
Staphylococcus aureus mastitis in dairy sheep ranges from subclinical mastitis to lethal gangrenous mastitis. Neither the S. aureus virulence factors nor the host-factors or the epidemiological events contributing to the different outcomes are known. In a field study in a dairy sheep farm over 21 months, 16 natural isolates of S. aureus were collected from six subclinical mastitis cases, one lethal gangrenous mastitis case, nasal carriage from eight ewes and one isolate from ambient air in the milking room. A genomic comparison of two strains, one responsible for subclinical mastitis and one for lethal gangrenous mastitis, was performed using multi-strain DNA microarrays. Multiple typing techniques (pulsed-field-gel-electrophoresis, multiple-locus variable-number, single-nucleotide polymorphisms, randomly amplified polymorphic DNA, spa typing and sas typing) were used to characterise the remaining isolates and to follow the persistence of the gangrenous isolate in ewes’ nares. Our results showed that the two strains were genetically closely related and they shared 3 615 identical predicted open reading frames. However, the gangrenous mastitis isolate carried variant versions of several genes (sdrD, clfA-B, sasA, sasB, sasD, sasI and splE) and was missing fibrinogen binding protein B (fnbB) and a prophage. The typing results showed that this gangrenous strain emerged after the initial subclinical mastitis screening, but then persisted in the flock in the nares of four ewes. Although we cannot dismiss the role of host susceptibility in the clinical events in this flock, our data support the hypothesis that S. aureus populations had evolved in the sheep flock and that S. aureus genetic variations could have contributed to enhanced virulence.
影响因子：
6.4
作者：
Lina, G;Bohach, GA;Mariuzza, R
通讯作者：
Mariuzza, R
影响因子：
3.5
作者：
Iandolo, JJ;Worrell, V;Roe, BA
通讯作者：
Roe, BA