Selective Targeting of Vibrios by Fluorescent Siderophore-Based Probes.

Siderophores are small molecules used to specifically transport iron into bacteria via related receptors. By adapting siderophores and hijacking their pathways, we may discover an efficient and selective way to target microbes. Herein, we report the synthesis of a siderophore-fluorophore conjugate VF-FL derived from vibrioferrin (VF). Using flow cytometry and fluorescence microscopy, the probe selectively labeled vibrios, including V. parahaemolyticus, V. cholerae, and V. vulnificus, even in the presence of other species such as S. aureus and E. coli. The labeling is siderophore-related and both iron-limited conditions and the siderophore moiety are required. The competitive relationship between VF-FL and VF in vibrios implies an unreported VF-related transport mechanism in V. cholerae and V. vulnificus. These studies demonstrate that the siderophore scaffold provides a method to selectively target microbes expressing cognate receptors under iron-limited conditions.