Lowenstein Jensen (LJ) Media- Composition, Principle, Preparation, Results, Uses


Mycobacterium tuberculosis is the causative agent of tuberculosis, a chronic infectious disease that affects mainly the lungs but can also involve other organs and tissues. Tuberculosis is one of the leading causes of death from infectious diseases worldwide, especially in low- and middle-income countries.

The diagnosis of tuberculosis relies on the detection and identification of Mycobacterium tuberculosis from clinical specimens, such as sputum, urine, blood, cerebrospinal fluid, etc. However, Mycobacterium tuberculosis is a slow-growing bacterium that requires special culture conditions and techniques to grow and isolate.

Lowenstein Jensen (LJ) Media is a selective medium commonly used for Mycobacterium cultivation and isolation of species from clinical specimens, most notably Mycobacterium tuberculosis. LJ medium was originally formulated by Lowenstein, who incorporated congo red and malachite green to inhibit unwanted bacteria. The present formulation comprises a glycerate egg-based medium and is based upon Jensens modification. Jensen modified Lowensteins medium by altering the citrate and phosphate contents, eliminating the congo red dye, and Increasing the concentration of malachite green. Gruft improved the selectivity of L. J. Medium by adding penicillin, nalidixic acid, and ribonucleic acid (RNA).

LJ A wide range of Mycobacteria can grow in this medium, which can also be used for niacin testing. When grown on LJ medium, M. tuberculosis appears as brown, granular colonies (sometimes called "buff, rough and tough"). The medium must be incubated for a significant length of time, usually four weeks, due to the slow doubling time of M. tuberculosis (15–20 hours) compared with other bacteria.

LJ medium is one of the most popular means of culturing mycobacteria, as recommended by the International Union against Tuberculosis. It is widely used for the diagnosis of mycobacterial infections, testing antibiotic susceptibility of isolates, and differentiating different species of Mycobacterium (by colony morphology, growth rate, biochemical characteristics, and microscopy).

In this article, we will discuss the composition, principle, preparation, results interpretation, uses, and limitations of the LJ medium in detail.