LJ media is used for –
**Core Concept**
LJ (Lowenstein-Jensen) medium is a selective agar-based culture medium used for the isolation and growth of Mycobacterium species, particularly M. tuberculosis. It is a solid medium that provides a nutrient-rich environment for the growth of these slow-growing bacteria.
**Why the Correct Answer is Right**
The LJ medium is composed of a combination of nutrients, including asparagine, glycerol, and malachite green, which inhibits the growth of other bacteria while allowing M. tuberculosis to grow. The medium also contains a high concentration of salt, which helps to inhibit the growth of contaminants. When incubated at a temperature of 37°C for 4-6 weeks, the LJ medium supports the growth of M. tuberculosis, allowing for the isolation and identification of this pathogen.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because LJ medium is not used for the isolation of Staphylococcus species, which can be grown on other types of media such as mannitol salt agar.
**Option B:** This option is incorrect because LJ medium is not used for the isolation of Pseudomonas species, which can be grown on other types of media such as Cetrimide agar.
**Option C:** This option is incorrect because LJ medium is not used for the isolation of Candida species, which can be grown on other types of media such as Sabouraud agar.
**Clinical Pearl / High-Yield Fact**
It's essential to note that LJ medium is a slow-growing medium, and culture results may take several weeks to obtain. Therefore, rapid diagnostic tests such as the GeneXpert MTB/RIF assay are often used in conjunction with LJ medium to quickly identify and detect M. tuberculosis.
**Correct Answer:** C.