Pillai P, Srinivasan U, Zhang L, Borchardt S M, Debusscher J, Marrs C F, Foxman B
Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA.
Epidemiol Infect. 2009 Oct;137(10):1420-5. doi: 10.1017/S0950268809002167. Epub 2009 Mar 4.
Streptococcus agalactiae is a genetically diverse organism; when typed by pulsed-field gel electrophoresis (PFGE), multiple types appear within a single serotype. We tested whether S. agalactiae PFGE types correspond to a specific serotype within individuals, and different individuals from the same geographic area. A total of 872 S. agalactiae isolates from 152 healthy individuals were classified by PFGE and capsular serotype. Serotype V was the most homogeneous (Simpson's diversity index 0.54); and types III, II and Ib were mostly heterogeneous (Simpson's diversity index 0.90). Within an individual, isolates with the same PFGE patterns had identical capsular types, but across individuals the same PFGE types sometimes occurred in different serotypes. Capsular type alone is insufficient to define epidemiological relatedness. Although PFGE types appear to be a valid surrogate for capsular typing of isolates from the same individual, it is not a valid surrogate for serotype in isolates from different individuals.
无乳链球菌是一种基因多样的微生物；采用脉冲场凝胶电泳（PFGE）分型时，单一血清型内会出现多种类型。我们测试了无乳链球菌PFGE型是否与个体内以及来自同一地理区域的不同个体中的特定血清型相对应。对来自152名健康个体的总共872株无乳链球菌分离株进行了PFGE和荚膜血清型分类。血清型V最为单一（辛普森多样性指数为0.54）；而血清型III、II和Ib大多具有异质性（辛普森多样性指数为0.90）。在个体内部，具有相同PFGE模式的分离株具有相同的荚膜类型，但在不同个体之间，相同的PFGE型有时会出现在不同的血清型中。仅荚膜类型不足以确定流行病学相关性。虽然PFGE型似乎是来自同一个体的分离株荚膜分型的有效替代指标，但对于来自不同个体的分离株的血清型而言，它并不是一个有效的替代指标。
