1Baird-Parker Agar (BPA)his is a selective medium for the isolation of Staphylococcus species. It has lithium chloride and glycine to inhibit the growth of Gram-negative bacteria and most Gram-positive bacteria except Staphylococcus. Egg yolk emulsion is added to detect lecithinase production and tellurite reduction. S. aureus colonies on BPA are black due to reduction of tellurite, and they exhibit a clear zone due to lecithinase activity on egg yolk.
2DNase Test AgarS. aureus produces the enzyme DNase which hydrolyses DNA. When S. aureus grows on this medium, the DNA is broken down, which can be visualised using a hydrochloric acid (HCl) solution: clear zones around the colonies indicate DNA breakdown.
3BACTECThis is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
4Proskauer and Beck’s MediumA liquid medium. The growth of M. tuberculosis causes turbidity.
5Middlebrook 7H9 BrothThis is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
6Dubos’ MediumA liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
7Tarshis MediumA blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
8m-ENDO AgarE. coli colonies appear as green with a metallic sheen, indicating lactose fermentation.
1BACTECThis is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
2Proskauer and Beck’s MediumA liquid medium. The growth of M. tuberculosis causes turbidity.
3Middlebrook 7H9 BrothThis is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
4Dubos’ MediumA liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
5Tarshis MediumA blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
6Tryptic Soy Agar (TSA)A general purpose medium. E. coli colonies are medium to large, with a shiny moist appearance.
7m-ENDO AgarE. coli colonies appear as green with a metallic sheen, indicating lactose fermentation.