Pneumococcal microbial surface components recognizing adhesive matrix molecules targeting of the extracellular matrix.

The attachment of bacteria to host cells and tissues, and their subsequent invasion and dissemination are key processes during pathogenesis. In this issue of Molecular Microbiology, Jensch and co-workers provide further molecular insight into these events during infection with the Gram positive bacterium Streptococcus pneumoniae. Their characterization of pneumococcal adherence and virulence factor B (PavB), a bacterial surface protein with orthologues in other streptococci, show that it binds to the extracellar matrix components fibronection and plasminogen by virtue of repetitive sequences-designated streptococcal surface repeats. In mice, a pavB mutant showed reduced nasopharyngeal colonization and was attenuated in a lung infection model. As discussed here in the context of the pneumococcus, the study of PavB highlights the central role during microbal pathogenesis of targetting the extracellular matrix by so-called microbial surface components recognizing adhesive matrix molecules (MSCRAMMs).