Novartis Vaccines and Diagnostics, Siena, Italy.
PLoS One. 2010 Feb 15;5(2):e9216. doi: 10.1371/journal.pone.0009216.
Streptococcus agalactiae is the primary colonizer of the anogenital mucosa of up to 30% of healthy women and can infect newborns during delivery and cause severe sepsis and meningitis. Persistent colonization usually involves the formation of biofilm and increasing evidences indicate that in pathogenic streptococci biofilm formation is mediated by pili. Recently, we have characterized pili distribution and conservation in 289 GBS clinical isolates and we have shown that GBS has three pilus types, 1, 2a and 2b encoded by three corresponding pilus islands, and that each strain carries one or two islands. Here we have investigated the capacity of these strains to form biofilms. We have found that most of the biofilm-formers carry pilus 2a, and using insertion and deletion mutants we have confirmed that pilus type 2a, but not pilus types 1 and 2b, confers biofilm-forming phenotype. We also show that deletion of the major ancillary protein of type 2a did not impair biofilm formation while the inactivation of the other ancillary protein and of the backbone protein completely abolished this phenotype. Furthermore, antibodies raised against pilus components inhibited bacterial adherence to solid surfaces, offering new strategies to prevent GBS infection by targeting bacteria during their initial attachment to host epithelial cells.
无乳链球菌是多达 30%健康女性的会阴部的主要定植菌，可在分娩时感染新生儿，导致严重败血症和脑膜炎。持续性定植通常涉及生物膜的形成，越来越多的证据表明，在致病性链球菌中，生物膜的形成是由菌毛介导的。最近，我们已经对 289 株 GBS 临床分离株中的菌毛分布和保守性进行了表征，并且已经表明 GBS 具有三种菌毛类型，1、2a 和 2b，由三个相应的菌毛岛编码，并且每种菌株携带一个或两个岛。在这里，我们研究了这些菌株形成生物膜的能力。我们发现，大多数生物膜形成者都携带菌毛 2a，并且通过插入和缺失突变体，我们已经证实，菌毛 2a 型，而不是菌毛 1 型和 2b 型，赋予了生物膜形成表型。我们还表明，缺失 2a 型的主要辅助蛋白并不影响生物膜的形成，而失活其他辅助蛋白和骨干蛋白完全消除了这种表型。此外，针对菌毛成分的抗体抑制了细菌对固体表面的黏附，为通过靶向细菌在其最初与宿主上皮细胞附着时来预防 GBS 感染提供了新的策略。
