The pathogenesis of infection and immune response

An understanding of the pathogenesis of infection, and the complex and fascinating 'relationship', or interaction, between the infecting organism and the host are advantageous when caring for patients with infections/infectious diseases, particularly as many of the clinical features of infection are as a consequence of the defence mechanisms mounted by the immune system. This article aims to provide a brief overview of the pathogenesis of infection, explaining how the two branches of the immune system, the innate/natural immune response, and the adaptive/acquired immune response, mount an attack against invading bacteria. Reference is made to bacteria such as Staphylococcus aureus, Clostridium difficile, Streptococcus pyogenes, Neisseria meningitidis and Mycobacterium tuberculosis, and their effect on the human host and the immune response, through the processes of attachment/entry, evasion of host defences, replication, and damage to the host.