Enterohemorrhagic Escherichia coli senses Oxygen to increase its virulence and colonization in the intestine
Pathogens adapt to the host gut ecosystem by precisely regulating the expression of their metabolism and virulence genes. Among the many regulatory factors, we identified ArcA as a key factor regulating the virulence repertoire of EHEC O157:H7. Central to our findings is the excellence of the ArcAB two-component system in sensing changes in oxygen levels and exerting tight control over the expression of virulence factors in EHEC. This process has not only been observed under controlled laboratory conditions, but has also been demonstrated in the complex environment of a living mouse model. Our study highlights the complexity of the pathogen in managing its energy resources to express virulence factors at the right time to ensure efficient colonization of the host.