What is the primary function of the bacterial capsule?

The primary function of the bacterial capsule is to protect against phagocytosis. A capsule is a thick polysaccharide layer that surrounds the bacterial cell wall, providing a physical barrier that prevents immune cells, particularly macrophages and neutrophils, from engulfing and destroying the bacteria. This protective feature enhances bacterial virulence by allowing the organism to evade the host's immune response, leading to increased survival and persistence within a host.

This capability is crucial for pathogenic bacteria, as it enables them to withstand the host's defensive mechanisms. The presence of a capsule can significantly increase the likelihood of infection by allowing the bacteria to escape clearance by the immune system.