Pathogenic and Virulence Mechanisms of Intracellular Bacteria: An Insight in Designing Appropriate Therapeutic Approach

Intracellular bacteria can survive and multiply inside phagocytes. Successful intracellular bacterial pathogens have evolved complex and efficient methods to overcome innate and adaptive immune responses. There are several pathogenic and virulence factors that are used by these pathogens to evade the immune system. Pathogenic intracellular bacteria prevent phagosome lysosome fusion, impair the respiratory burst and also inhibit chemotaxis and interfere with macrophage activation. They can also inhibit antigen presentation, destruct phagosome membrane, resist antibacterial peptides and also parasitize non-professional cells. Secreted proteins and siderophores also assist the survival and multiplication of intracellular bacteria within host cells. The complement and adaptive immunity may be paralyzed for successful survival of some of these bacteria. Some intracellular bacteria carry virulence genes that regulate host factors. Understanding the pathogenic mechanisms and the virulence factors of intracellular bacteria are crucial in underlying the pathogenesis and in designing appropriate therapeutic approach. Hence, research should be conducted at molecular and genetic level to further characterize and understand the pathogenic and virulence factors associated with intracellular bacteria. Keywords: Evasion, Innate and Adaptive Immunity, Intracellular Bacteria, Pathogenic and Virulence Factor