Abstract:
The species belonging to Mycobacterium tuberculosis complex (MTC) display characteristic
serpentine cord formation in liquid cultures. The factor responsible for the cord formation is
trehalose-6,6-dimycolate (TDM), a component of the mycobacterium cell wall that is
responsible for MTC virulence. Thus cord formation is considered a definitive diagnostic
character of MTC. Microscopic observation drug susceptibility assay (MODS), based on this
character, is widely used for identification of multi drug resistant tuberculosis (MDR-TB).
