After I did some disc diffusion assays with a fast growing Mycobacteria I now want to do this using M. tuberculosis but I read that you cannot use Mueller Hinton agar with this. Does anyone know why not? Also what is a good agar to use if I want to do the disk diffusion assay with M. tuberculosis that will make a good lawn? Will tryptic soy agar work?
I have no experience with the use of Mueller Hinton for mycobacteria, but I can tell that the standard medium works pretty well.
The standard solid medium for M.tb is Middlebrook 7H10 and 7H11 (more amino acids). This medium is optimized for culturing mycobacteria because it contains albumin, inorganic salts and oleic acid to promote growth of mycobacteria. Oleic acid seems to be quite relevant for mycobacterial metabolism and this substance is not included in Mueller Hinton broth, which is generally quite basic. The Middlebrook medium does also contain compounds that should inhibit growth of contaminants (malachite green).
DOI: 10.1002/9780471729259.mc10a01s6
Mueller Hinton Agar cannot be used in this evaluations because, It does not have numerous necessary components for the selective growth of the Mycobacterium tuberculosis bacteria (polymyxin B, amphotericin B, carbenicillin and trimethoprim lactate).
I recommend using the Stonebrink and Löwenstein-Jensen solid media for this study. If starting from a pure culture I propose to dilute the bacteria first in glycerated broth and immediately sow in Stonebrink or Löwenstein-Jensen (37 °C /dark, 35-34 days), in a homogeneous way.
Value the use of the technique: well diffusion also called agar gel drilling (≈ 0.2 mL / well / concentration) or minimum inhibitory concentration in glycerated broth.
Ok thank you very much for the information and explanations, Middlebrook 7H11 is the recommended media by E-test, but I was advised that the components in BSA in this media has a potential to bind with my compounds so thank you very much for the suggestions of other media.
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