Molecular analyses of the iron starvation response in the coagulase-negative group of staphylococci

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Iron is required by all life forms, yet it's very low availability frequently make it a growth-limiting nutrient. This presents significant problems to all life forms which must therefore find innovative ways to gain access to this nutrient in order to survive. This is no less true for bacteria. Many bacteria emit what are called siderophores into the surrounding environment to bind iron and deliver iron back to the bacterial cell. Many bacteria that are found in association with humans and animals can also capture iron out of hemoglobin as a way to support their own survival. A group of bacteria called coagulase-negative staphylococci are typically referred to as commensals, that is, they live in close association with animals and humans and do not cause disease but rather promote health. Indeed, experts estimate that there are actually 10 times as many bacteria found in and on mammals than there are mammalian cells. For coagulase-negative staphylococci, their very presence on skin and mucous membranes actually helps defend against infection by disease-causing bacteria. This research will identify the ways in which these bacteria access iron as a means to survive and and grow. With our NSERC-funded history of characterizing iron acquisition systems in the highly infectious Staph aureus bacterium, the research to be undertaken on the commensal bacteria over the next five years will provide us with a fundamental understanding of similarities and differences in iron acquisition systems in major disease-causing bacteria versus important commensal bacteria that are much less likely to cause infection. This research will inform us about the possibilities of whether antibacterials that might target iron acquisition processes in the disease-causing bacteria will have collateral effects on commensal bacteria.