Department of Pathology, Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, St. Norwida 31, 50-375 Wrocław, Poland.
Department of Pathology, Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, St. Norwida 31, 50-375 Wrocław, Poland.
Vet Microbiol. 2018 Feb;214:28-35. doi: 10.1016/j.vetmic.2017.12.004. Epub 2017 Dec 8.
The aim of this paper is to describe a novel subpopulation of Staphylococcus haemolyticus isolated from intramammary gland infections (IMI) in cattle. In total, eight isolates originating from milk samples from two unrelated dairy farms were examined phenotypically (using the ID 32 STAPH system) and genotypically. These isolates had almost identical sequences of each of the housekeeping genes examined (dnaJ, rpoB and sodA) but these sequences displayed similarity of only ∼92.5%, 95.0% and 96.8%, respectively, with known S. haemolyticus sequences. The atypical isolates could also be distinguished biochemically by the positive β-galactosidase test (with 2-naphthyl-β-d-galactopyranoside as the substrate). All the isolates were identified as S. haemolyticus upon MALDI-TOF analysis but half of them, that achieved scores 1.7-1.999 (not reliable species identification), required expanding the commercial database for secure identification. Our study has shown that IMI in cattle may be caused by two distinct subpopulations of S. haemolyticus, differing clearly by some genotypic and phenotypic properties. The first of these subpopulations seems to be common to many hosts (including humans), whereas the second (possibly at the subspecies rank) is, so far, found only in cattle.
本文旨在描述从奶牛乳腺炎感染（IMI）中分离出的一种新型溶血葡萄球菌亚群。总共检查了来自两个无关联的奶牛场的 8 个分离株的表型（使用 ID 32 STAPH 系统）和基因型。这些分离株的每个看家基因（dnaJ、rpoB 和 sodA）的序列几乎完全相同，但这些序列与已知的溶血葡萄球菌序列的相似度分别为约 92.5%、95.0%和 96.8%。这些非典型分离株也可以通过阳性β-半乳糖苷酶试验（以 2-萘基-β-d-半乳糖吡喃糖苷为底物）进行生化区分。所有分离株在 MALDI-TOF 分析中均被鉴定为溶血葡萄球菌，但其中一半（得分在 1.7-1.999 之间，鉴定结果不可靠）需要扩展商业数据库以进行可靠的鉴定。我们的研究表明，奶牛乳腺炎可能由两种不同的溶血葡萄球菌亚群引起，这些亚群在一些遗传和表型特性上存在明显差异。其中第一个亚群似乎存在于许多宿主（包括人类）中，而第二个亚群（可能处于亚种水平）目前仅在牛中发现。
