ARED: Antibiotic Response determined by Euclidean Distance with highly sensitive Escherichia coli biosensors

Abstract

Abstract Antimicrobial Resistance is challenging healthcare and food security and is driven by antibiotic overuse and environmental pollution. Longitudinal monitoring of antibiotic residue would help to track pollution sources and assess the effect of interventions. Here we propose a novel high-throughput monitoring method. We mutagenized E. coli MG1655 and identified and characterized 12 antibiotic-sensitive biosensors (ABSBs) with different genotypes by a newly developed method called Antibiotic Response determined by Euclidean Distance (ARED), based on growth (OD600) and metabolic activity (resazurin). The ABSBs contain nonsense or frameshift mutations in expected genes, like those coding for efflux pumps and lipopolysaccharide biosynthesis enzymes, as well as mutations in genes lesser or not known to be important for antibiotic sensitivity. Resazurin-based ARED can achieve antibiotic detection in the ng/mL range for most antibiotics tested in aqueous solutions. Our study shows that mutagenesis of E. coli can generate a tremendous shift in antibiotic sensitivity and that quantification of metabolic activity with ARED is a straightforward manner to monitor antibiotic activity in aqueous solutions. We propose that this method can be adopted for any collection of cell strains that possess differential antibiotic sensitivity and thus can be implemented for widespread monitoring of samples with unknown antibiotic complexion and origin.