Regulation of iron-uptake systems in Vibrio vulnificus, a ferrophilic bacterium

Vibrio vulnificus is a gram-negative ferrophilic bacterium that causes necrotizing wound infections and fatal septicemia, which mainly occur in patients with elevated levels of iron in serum or tissue, despite the presence of well-developed bacterial multiple iron-uptake systems (IUSs). These IUSs play important roles in the pathogenesis of V. vulnificus infections and are primarily regulated at the transcriptional level by a ferric uptake regulator called Fur responding to iron availability and their own specific regulators. Recent studies have shown that the IUSs are also controlled by other global regulators, including cyclic AMP-receptor protein responding to carbon availability and SmcR, a master regulator of the quorum-sensing system responding to bacterial density. This review presents an update on this sophisticated regulation of IUSs in V. vulnificus.