Middlebrook 7H9 broth is a liquid growth medium specially used for culture of Mycobacterium species, notablyMycobacterium tuberculosis.[1]
Middlebrook 7H9 broth supports the growth of mycobacterial species when supplemented with nutrients such as glycerol, oleic acid, albumin, and dextrose, except forMycobacterium bovis, which is inhibited by glycerol. Cultures should be read within 5–7 days after inoculation and once a week thereafter for up to 8 weeks.
Middlebrook broth is commonly used in the preparation of inocula for antimicrobial assays, biochemical tests (arylsufatase and tellurite reduction), and maintenance of stock strains.
Additionally, 7H9 broth is used as a medium in themycobacteria growth indicator tube.[2]