Chapter 9 - Capsule Structure, Synthesis, and Regulation

Abstract

The polysaccharide capsule (CPS) of Streptococcus pneumoniae is the single most critical factor underpinning the virulence of this major human pathogen. Indeed, CPS has been the focus of a plethora of research, and has played a fundamental role in a number of seminal findings, including that DNA is the carrier of genetic material. The importance of CPS to virulence is predominantly through its ability to enable bacteria to evade opsonophagocytic killing, as is discussed elsewhere in this book. Furthermore, CPS is the target for the current breed of vaccines, which have proved successful in significantly decreasing the level of invasive pneumococcal disease. This chapter focuses on this major virulence factor, describing its general structure, methods for biosynthesis, and the various modes of regulation which influence CPS levels. A greater understanding of such features is critical in order to uncover novel ways to continue the fight against this major human killer.