Enzyme-Activated, Chemiluminescent Siderophore-Dioxetane Probes Enable the Selective and Highly Sensitive Detection of Bacterial Pathogens

The sensitive detection of bacterial infections is a prerequisite for their successful treatment. The use of a chemiluminescent readout was so far hampered by an insufficient probe enrichment at the pathogens. We coupled siderophore moieties, that harness the unique iron transport system of bacteria, with enzyme-activatable dioxetanes and obtained seven trifunctional probes with high signal-to-background ratios (S/B=426-859). Conjugates with efficient iron transport capability into bacteria were identified through a growth recovery assay. All ESKAPE pathogens were labelled brightly by desferrioxamine conjugates, while catechols were weaker due to self-quenching. Bacteria could also be detected inside lung epithelial cells. The best probe 8 detected 9.1×10³ CFU mL⁻¹ of S. aureus and 5.0×10⁴ CFU mL⁻¹ of P. aeruginosa, while the analogous fluorescent probe 10 was 205–305fold less sensitive. This qualifies siderophore dioxetane probes for the selective and sensitive detection of bacteria.