Vibrio and Aeromonas species are ubiquitous bacteria in aquatic environments worldwide. Many of the species are important pathogens for humans and/or aquatic animals. Several iron acquisition strategies have been developed by vibrios and aeromonads in order to get this essential element for surviving in their host and in aquatic habitats. All species studied so far have the ability to synthesize siderophores to sequester iron from the cell environment and transport it through their respective cognate outer membrane receptors. It has been demonstrated that this capacity is a relevant virulence factor for human and animal pathogens. Furthermore, all species studied can utilize exogenous siderophores, made by other bacteria. Another iron acquisition system described in both genera involves the use of heme as a source of iron, by a mechanism very well conserved among all species, which involves a heme transporter that includes a specific TonB-dependent outer membrane receptor(s) and an ABC-type inner membrane transporter. Alternative systems based on ferrous or ferric iron transporters have been reported in V. cholerae. How the different iron acquisition systems work together to supply iron to the cell and how they are used in the different environments where vibrios and aeromonads can be found is still an open question.

Further reading: Iron Uptake and Homeostasis in Microorganisms

Labels: Aeromonas, Exogenous heme, Heme biosynthesis pathway, Heme degradation, Heme efflux, Heme uptake, Iron acquisition strategies, Iron deficiency, Iron extraction, Iron uptake in Vibrio, vibrio