Dawit Woldemeskel

There is an error in the penultimate sentence of the Materials and Methods section under the subheading “Chemicals and antibiotics.” The correct sentence is: The final concentration of 2 ?g/ml RIF and 0.2 ?g /ml INH were used in the MTT assay.

With the spread of multidrug-resistant tuberculosis (MDR-TB) strains there is an increasing need for new accurate and cost-effective methods for a rapid diagnostic and drug susceptibility testing (DST), particularly in low-income countries where tuberculosis is hyperendemic. A colorimetric assay using 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) has been suggested as a promising method for DST, especially to rifampicin.