RAPID ELECTROCHEMICAL ASSAY FOR ANTIBIOTIC AND CYTOTOXIC DRUG SUSCEPTIBILITY IN MICROORGANISMS

摘要

This invention presents rapid methods for evaluating the effects of antimicrobial compounds on microorganisms based upon the microorganism's ability to transport electrons to an external chemical oxidant (a mediator) that is added to the microorganism sample. The mediator interacts with the terminal components of the respiratory pathway and the extent of its consumption is related to the ability of the microorganism to respire. However, under the assay conditions described herein the extent of mediator consumption is different from the microorganisms' ability to consume oxygen, due to the addition of metabolizable compounds to the assay mixtures. The consumed mediator is subsequently measured electrochemically (amperometrically or coulometrically) at the working electrode of a standard two-electrode or threeelectrode electrochemical cell. The electrochemical signals (change of current or charge with time) obtained with microorganism suspensions incubated in the absence and presence of antimicrobial compounds are significantly different. These signal differences can be used to screen for antimicrobial effectiveness of antibiotic drugs against clinically important multi-drug-resistant organisms, to screen for the presence of unlawful levels of antibiotic compounds in foodstuffs, or to screen potential new antimicrobial compounds for effectiveness against different species of microorganisms.