Modified method for testing the quality of albumin-containing enrichments used in growth media for mycobacteria.

Many commercially available media for cultivation of mycobacteria have failed to support the growth of these organisms. This is especially true of media prepared with albumin-containing enrichments. Earlier, we developed a method for rapid identification of good albumin enrichments for agar-based media used to test the susceptibility of tubercle bacilli to pyrazinamide. The method was modified to make testing of the acceptability of albumin enrichments for primary isolation media for mycobacteria possible. We describe here a simple turbidimetric test using a specific Bacillus subtilis strain to assay quickly (24 h) different lots of albumin-containing enrichments that may be used in the preparation of growth media for mycobacteria.