Dubos Broth Base, 5 kg

Tuberculosis remains a major global public health problem worldwide. Mycobacterium tuberculosis , the causative agent of tuberculosis in man, is carried in airborne particles known as droplet nuclei that are generated when patients with pulmonary tuberculosis cough. Infections occur when a susceptible person inhales the droplet nuclei containing the bacterium (1). Dubos Broth is formulated as per Dubos, et al (2), and is a modification of the medium originally formulated by Dubos and Davis (3) and Dubos and Middlebrook (4). Dubos media contain Casein enzymic hydrolysate and L-aspargine as sources of nitrogen. Polysorbate 80, an oleic acid ester also acts as a surfactant. It therefore supplies the essential fatty acids for the replication of Mycobacteria and also increases the growth by dispersing the bacilli. The phosphates (together with calcium chloride) buffers the media as well as serve as sources of phosphates. Magnesium sulphate, zinc sulphate, copper sulphate and ferric ammonium citrate provide trace metals and sulphates. Bovine albumin binds the free fatty acids, which may be toxic to Mycobacteria. Albumin is heat treated to cinactivate the lipase, which may release fatty acids from Polysorbate 80 incorporated in the medium. Dubos Broth Base enriched with serum will generally initiate growth from smaller inocula and yield more luxuriant growth than the basal medium enriched with albumin V. Growth is generally more granular with the serum enrichment, while it is more diffused with albumin enrichment. Maximum care should be taken while handling Mycobacterial cultures, as they are highly infectious. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label. References: 1. Murray P. R., Baron J. H., Pfaller M. A., Jorgensen J. H. and Yolken R. H., (Ed.), 2003, Manual of Clinical Microbiology, 8th Ed., American Society for Microbiology, Washington, D.C. 2. Dubos R. J., Fenner F. and Pierce C. H., 1950, Am. Rev. Tuberc., 61:6 6. 3. Dubos R. J. and Davis B.D., 1946, J. Exp. Med., 83:409. 4. Dubos R. J., and Middlebrook G., 1947, Am. Rev. Tuberc., 56:334