Bacterial Secretion Systems
Bacteria that live in contact to eukaryotic cells greatly benefit from being able to manipulate host cell behaviour. One of the most direct and elegant ways to reach this aim is the type III secretion system (T3SS), a molecular syringe also known as “injectisome”, used by gram-negative bacteria to inject effector proteins into host cells.
The T3SS is essential for virulence in many important human pathogens, including Salmonella, Shigella, and pathogenic Escherichia coli, that cause several millions of deaths per year. It is also important in hospital infections, for example by Pseudomonas aeruginosa, where presence of a functional T3SS is associated with higher mortality in animal models and increased antibiotic resistance, severe disease, and a bad prognosis in infected humans.