Keywords
Mycobacterium tuberculosis
drug resistance
How to Cite
Abstract
The microtitre plate method used to determine the minimal inhibitory concentration has been compared with the method of tube macrodilution and the radiometric method, for the purpose of evaluating this method in testing second-line drugs and new compounds which may have a potential effect against Mycobacterium tuberculosis. The drug used was isoniazid and 34 strains were tested, besides the standard strain H37Ra. Out of those strains, 26 were sensitive to isoniazid and eight were resistant to it. The results obtained showed that the plate method gave 32 concordant results and three discordant ones. There was a good correlation between the results of these methods and the results of the radiometric method. The sensitivity and specificity of this method were good, being very similar to the ones for the radiometric method. The conclusion is that the microdilution plate method is appropriate to test the effect of drugs or compounds against M.tuberculosis. It is an inexpensive technique that is easy to perform and does not require any equipment in its use.
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