L-J Gruft

Selectively isolate and cultivate Mycobacterium spp. using Thermo Scientific™ Remel™ Lowenstein-Jensen (L-J) Medium, L-J Gruft, and L-J Mycobactocel. Medium consisting of congo red and malachite green dyes was formulated by Lowenstein to cultivate mycobacteria¹. This medium was modified by Jensen by replacing congo red with citrate and phosphate contents and increasing the malachite green concentration². L-J Medium used for recovery of pathogenic Mycobacterium spp. was found to be superior to other media tested, including ATS (American Trudeau Society) Medium^3,4.

Selectively isolate and cultivate Mycobacterium spp. using Lowenstein-Jensen (L-J) Medium, L-J Gruft, and L-J Mycobactocel.

• Selective – Antibiotics in the medium make the medium selective for Mycobacterium while inhibiting contaminating bacteria.
• Ready to use – Convenience of prepared media.

L-J Medium is a glycerated egg-potato medium. The glycerol and egg mixture provide fatty acids and protein required for the metabolism of mycobacteria. L-J Medium was modified by Gruft by adding ribonucleic acid as a growth stimulant and penicillin and nalidixic acid as selective inhibitors of contaminating bacteria⁵. Ribonucleic acid increases the percentage of positive cultures over the standard L-J Medium. The selectivity of L-J Medium was increased by incorporating cycloheximide, lincomycin, and nalidixic acid and was formulated by Petran and Vera⁶.