Method and apparatus utilizing agar diffusion technique for determining quantitative drug concentration parameter

摘要

An apparatus for using the continuous-gradient disk diffusion technique to obtain quantitative minimum inhibitory concentrations and inhibitory quotients comprises an electronic caliper operatively coupled to a microprocessor for feeding thereto signals coding the diameters of bacteria-growth inhibition zones measured by the caliper. In response to the signals, the microprocessor automatically calcula es by means of a regression-type analysis the minimum inhibitory concentrations of the drugs, as determinable based on a correlation with results by a broth dilution test, with respect to the bacterium under study. The microprocessor also calculates, in response to the signals from the electronrc caliper, inhibitory quotients with respect to a plurality of different body fluids such as bile, blood and cortical spinal fluid. The apparatus may also be used to determine unknown concentrations of antimicrobial drugs by using the disk diffusion technique and a regression analysis.