A rapid and label-free method for the detection of drug-resistant pathogens is in high demand for wastewater-based epidemiology. As recently shown, the extent of electrical current production (Ic) is a useful indicator of a pathogen's metabolic activity. Therefore, if drug-resistant bacteria have extracellular electron transport (EET) capability, a simple electric sensor may be able to detect not only the growth as a conventional plating technique but also metabolic activity specific for drug-resistant bacteria in the presence of antibiotics. Here, one of the multidrug-resistant pathogens in wastewater, Klebsiella pneumoniae, was shown to generate Ic, and the extent of Ic was unaffected by the microbial growth inhibitor, kanamycin, while the current was markedly decreased in environmental EET bacteria Shewanella oneidensis. Kanamycin differentiated Ic in K. pneumonia and S. oneidensis within 3 h. Furthermore, the detection of K. pneumoniae was successful in the presence of S. oneidensis in the electrochemical cell. These results clarify the advantage of detecting drug-resistant bacteria using whole-cell electrochemistry as a simple and rapid method to detect on-site drug-resistant pathogens in wastewater, compared with conventional colony counting, which takes a few days.
Keywords: antibiotic-resistant pathogen; extracellular electron transport; single-potential amperometry; wastewater-based epidemiology; whole-cell electrochemistry.