Mycobacterial biofilm: Structure and its functional relevance in the pathogenesis

The Mycobacterium genus harbors a few of the most virulent bacteria known to humanity that have caused global destruction in the form of tuberculosis (TB) disease. Most of the species grouped under the genus are opportunistic pathogens that cause chronic disease. Mycobacteria use multiple strategies to increase their survivability in a hostile environment. One of the strategies is the formation of biofilm that aids in setting up a protected coterie for the bug. The role of biofilm in enhancing virulence and treatment strategy in mycobacterial infections is often neglected. Recently, few groups have observed that the biofilm-resident mycobacteria are unresponsive to many antibiotics, leading to drug-resistant strains. It also imparts a unique colony morphology to the bacteria and makes them more virulent. These findings have necessitated the elucidation of mechanisms leading to biofilm development and chronic infections and novel prophylactic strategies to tackle them. The present chapter discusses the molecular mechanisms employed by different mycobacterial species to form an active biofilm and their role in infection in humans.