Zadoks Ruth N, Tikofsky Linda L, Boor Kathryn J
Department of Food Science, Cornell University, Ithaca, NY 14853, USA; Quality Milk Production Services, 22 Thornwood Drive, Cornell University, Ithaca, NY 14850-1263, USA.
Vet Microbiol. 2005 Aug 30;109(3-4):257-65. doi: 10.1016/j.vetmic.2005.05.008.
Streptococcus uberis is a major cause of bovine mastitis and infections commonly result from environmental exposure to the pathogen. To identify specific sources of mastitis-causing S. uberis strains, samples were collected monthly from the environment and feces of dry cows in a grazing herd. Environmental and fecal strains of S. uberis were compared to those found in milk. S. uberis was detected in 63% of 94 environmental samples, including water, soil, plant matter, bedding material, flies, and hay, in 23% of 107 fecal samples, and in 4% of 787 milk samples. Automated PvuII ribotyping revealed 48 ribotypes among 266 isolates. Per sample, up to five ribotypes were detected. The distribution of ribotypes did not differ significantly among environmental, fecal and milk samples. Specific environmental sources or strains of udder-pathogenic S. uberis were not identified. Fecal shedding was not persistent and did not differ between dry-off and calving. The proportion of fecal samples containing S. uberis was highest during the summer grazing season. S. uberis was common in farm soil (31 of 35 samples) but not in non-farm soil (0 of 11 samples). We hypothesize that fecal shedding of S. uberis may play a role in maintenance of S. uberis populations in the dairy ecosystem.
乳房链球菌是引起奶牛乳腺炎的主要原因，感染通常是由于环境暴露于该病原体所致。为了确定引起乳腺炎的乳房链球菌菌株的具体来源，每月从一个放牧牛群中的干奶牛的环境和粪便中采集样本。将乳房链球菌的环境菌株和粪便菌株与牛奶中发现的菌株进行比较。在94个环境样本（包括水、土壤、植物物质、垫料、苍蝇和干草）中的63%、107个粪便样本中的23%以及787个牛奶样本中的4%检测到了乳房链球菌。自动化PvuII核糖体分型显示，在266株分离物中有48种核糖体类型。每个样本最多检测到五种核糖体类型。环境、粪便和牛奶样本中核糖体类型的分布没有显著差异。未确定乳房致病性乳房链球菌的特定环境来源或菌株。粪便排菌并不持续，在干奶期和产犊期之间也没有差异。在夏季放牧季节，含有乳房链球菌的粪便样本比例最高。乳房链球菌在农场土壤中很常见（35个样本中有31个），但在非农场土壤中则没有（11个样本中有0个）。我们推测，乳房链球菌的粪便排菌可能在维持奶牛养殖生态系统中乳房链球菌种群方面发挥作用。
