Once the iron-siderophore complex is formed, it is taken up by siderophore receptors on the bacterial surface and then that iron is brought into the bacterium.Once pathogens attach to host cells, they can cause direct damage as the pathogens use the host cell for nutrients and produce waste products.
Examples of these opportunistic pathogens include Pseudomonas aeruginosa, Burkholderia cenocepacia, and Mycobacterium avium. Chlamydophila, Ehrlichia, Rickettsia) have the ability to only grow and replicate inside other cells.
Even these intracellular infections may be asymptomatic, requiring an incubation period. These pathogens can cause pneumonia or urinary tract infection and may be involved in coronary heart disease.
Bacterial pathogens often cause infection in specific areas of the body. Iron is required for humans, as well as the growth of most bacteria.
To obtain free iron, some pathogens secrete proteins called siderophores, which take the iron away from iron-transport proteins by binding to the iron even more tightly.
As pathogens multiply and divide inside host cells, the cells usually rupture and the intercellular bacteria are released. coli, Shigella, Salmonella, and Neisseria gonorrhoeae, can induce host epithelial cells to engulf them in a process resembling phagocytosis.
The pathogens can then disrupt host cells as they pass through them and be extruded from host cells by a reverse phagocytosis process, enabling them to enter other host cells.These infections can become quite serious creating a systemic inflammatory response resulting in massive vasodilation, shock, and death.Other bacteria are opportunistic pathogens and cause disease mainly in people suffering from immunosuppression or cystic fibrosis.Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as Streptococcus and Pseudomonas, and foodborne illnesses, which can be caused by bacteria such as Shigella, Campylobacter, and Salmonella.Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy.Some bacteria can also penetrate host cells by excreting enzymes and by their own motility; such penetration can itself damage the host cell.