Bacteria respond to their environments – to ensure their own survival and proliferation – using two-component systems (TCSs). These systems consist of a bacterial receptor and a response regulator that changes bacterial behavior by modifying gene expression. Most bacterial receptors and response regulators are exclusive pairs that do not interact with components of other TCSs.
In the Jan. 10 issue of Science Signaling, Maria Hadjifrangiskou, Ph.D., and colleagues demonstrate that two different TCSs interact in a strain of uropathogenic E. coli – bacteria that cause urinary tract infections.
They show that the bacterial receptor of one TCS interacts with two regulators (its own and another) to mediate the response to ferric iron. Pretreatment of clinical isolates of uropathogenic E. coli with ferric iron increased tolerance to the antibiotic polymyxin B and required both TCSs.
The study identifies a unique example of physiologically relevant cross-talk between TCSs and provides a potential mechanism for antibiotic resistance in some strains of uropathogenic E. coli.
This research was supported by grants from the National Institutes of Health (AI107052, GM007628) and by Institutional Academic Professional Support and the National Science Foundation.
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