[A spectroturbidimetric method of rapid evaluation of microbial sensitivity to antibiotics]

A rapid spectroturbidimetric method for estimation of the microbial sensitivity to antibiotics is described. It provides quantitative determination of significant structural parameters of bacterial suspensions, such as the average values of the cell radius or the radius of the cell conglomerates r lambda, their numerical concentration N and the concentration of the intact cells by the dry weight C. The relative changing of the biomass during the culture growth is a reliable index of the microbial sensitivity to the antibiotic effect. The changing of the biomass is determined by direct estimation of C, but not by the suspension turbidity measured at one light wavelength. The collection strains E. coli M-17 and S. aureus 209P were used. The spectra of the optical density were measured with the use of the apparatus made in the USSR. It was noted that the resolving capacity and realization rate of the spectroturbidimetric method wee higher than those of the routine agar diffusion method. The spectroturbidimetric method provides determination of the culture sensitivity to several antibiotics for 4 hours.