1P-218 Rapid detection of Gram-negative bacteria using Colistin as a ubiquitous targeting ligand

Gram-negative bacteria is a serious cause of infections, which have to be rapidly diagnosed for specific and early treatment. Conventional methods include microbial culture, immunoassays, and nucleic acid testing, however have limitations in involving time-consuming procedures, lack of specific ligands, or expensive equipments. Colistin bind specifically to the lipopolysaccharide on the cell wall of Gram-negative bacteria. Herein, we apply Colistin as the ligand to ubiquitously target Gram-negative bacteria for rapid detection with high selectivity. We prepared colistin modified with Cy3, to rapidly label and visualize Gram-negative bacteria. Labeling of the bacteria with colistin-Cy3 was done by incubation for 10 min, and we successfully observe bright fluorescence on Gram-negative bacteria by microscopy, as well as strong signals by quantification. This labeling method can be used as a rapid and simple molecular detection platform for ubiquitous detection of Gram-negative pathogens.