Baseggio N, Mansell P D, Browning J W, Browning G F
Department of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
Mol Cell Probes. 1997 Oct;11(5):349-54. doi: 10.1006/mcpr.1997.0126.
Pulsed-field gel electrophoresis (PFGE) was examined as a tool to differentiate strains of streptococci isolated from clinical and sub-clinical cases of bovine mastitis. Analysis of SmaI chromosomal digests of Streptococcus agalactiae, S. dysgalactiae subsp. dysgalactiae and S. uberis isolates revealed intraherd and interherd strain relationships within each species. Comparison of S. agalactiae isolates from the same herd revealed little variability in their SmaI restriction patterns indicating a single strain originating from a common source of infection. However, comparison of S. agalactiae isolates between herds showed that each herd was infected with a distinct strain. The restriction profiles from S. dysgalactiae subsp. dysgalactiae and S. uberis were more diverse and often multiple strains of both species were present within an individual herd, with some herds containing more than one representative of a particular strain. Interestingly, it was only observed with S. dysgalactiae subsp. dysgalactiae that some strains were present in more than one herd. PFGE was found to be a useful and reproducible method for the discrimination of different strains of the three most important species of streptococci responsible for bovine mastitis and to offer a means to identify environmental sources of infection.
脉冲场凝胶电泳（PFGE）被作为一种工具，用于区分从牛乳腺炎临床和亚临床病例中分离出的链球菌菌株。对无乳链球菌、停乳链球菌停乳亚种和乳房链球菌分离株的SmaI染色体酶切产物进行分析，揭示了每个物种内的 herd 内和 herd 间菌株关系。对来自同一 herd 的无乳链球菌分离株进行比较，发现它们的SmaI限制图谱差异很小，表明单一菌株源自共同的感染源。然而，对不同 herd 的无乳链球菌分离株进行比较表明，每个 herd 感染的是不同的菌株。停乳链球菌停乳亚种和乳房链球菌的限制图谱更为多样，且在单个 herd 中通常存在这两个物种的多个菌株，有些 herd 含有特定菌株的多个代表。有趣的是，仅在停乳链球菌停乳亚种中观察到某些菌株存在于多个 herd 中。发现PFGE是一种有用且可重复的方法，用于区分导致牛乳腺炎的三种最重要链球菌物种的不同菌株，并提供一种识别感染环境来源的手段。
