Biofilm formation in Streptococcus pneumoniae.
Bottom Line: Although neither the precise nature of these proteins nor the composition of the putative polysaccharide(s) is clear, it is known that choline-binding proteins are required for successful biofilm formation.However, much care needs to be taken when choosing strains for such studies because different S. pneumoniae isolates can show remarkable genomic differences.Multispecies and in vivo biofilm models must also be developed to provide a more complete understanding of biofilm formation and maintenance.
Affiliation: Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas and CIBER de Enfermedades Respiratorias, Madrid, Spain.Show MeSH
Related in: MedlinePlus
Mentions: Extracellular DNA (but apparently not RNA) and extracytoplasmic and surface‐exposed proteins appear to be critical elements of the matrix required for the initial attachment and maintenance of pneumococcal biofilms. Significant inhibitory and disintegrating effects on pneumococcal biofilms are seen when DNase I or proteases is added before or after biofilm development respectively (Fig. 2) (Moscoso et al., 2006). These findings have been independently confirmed (Hall‐Stoodley et al., 2008; Carrolo et al., 2010). It has recently been proposed that the spontaneous induction of temperate bacteriophages might constitute an important source of extracellular DNA for the pneumococcal biofilm matrix (Carrolo et al., 2010). This agrees with an early report showing that lysogenized S. pneumoniae strains are better biofilm formers than the corresponding cured strains (Loeffler and Fischetti, 2006). Other authors, however, report that DNase treatment does not significantly affect biofilm formation in vitro and suggest that DNA is likely not an essential constituent of biofilms formed under the experimental conditions they used (Muñoz‐Elías et al., 2008). It should be mentioned that competence induction and concomitant DNA release in pneumococcus strongly depends on the medium (Moscoso and Claverys, 2004).
Affiliation: Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas and CIBER de Enfermedades Respiratorias, Madrid, Spain.