Question

One of the common defense mechanism of pathogenic bacteria to avoid phagocytosis is the presence of

Answer 1

Some pathogenic bacteria are inherently able to resist the bactericidal components of host tissues, usually as a function of some structural property. For example, the poly-D-glutamate capsule of Bacillus anthracis protects the organisms against action of cationic proteins (defensins) in sera or in phagocytes. The outer membrane of Gram-negative bacteria is a permeability barrier to lysozyme and is not easily penetrated by hydrophobic compounds such as bile salts in the GI tract that are harmful to the bacteria. Pathogenic mycobacteria have a waxy cell wall that resists attack or digestion by most tissue bactericides. And intact lipopolysaccharides (LPS) of Gram-negative pathogens may protect the cells from complement-mediated lysis or the action of lysozyme.

Most successful pathogens, however, possess additional structural or biochemical features that allow them to resist the host cellular defense against them, i.e., the phagocytic and immune responses. If a pathogen breaches the host's surface defenses, it must then overcome the host's phagocytic response to succeed in an infection.