Mycobacterial Biofilms: Revisiting Tuberculosis Bacilli in Extracellular Necrotizing Lesions

Under detergent-free in vitro conditions, Mycobacterium tuberculosis, the etiological agent of tuberculosis in humans, spontaneously forms organized multicellular structures called biofilms. Moreover, in vitro biofilms of M. tuberculosis are more persistent against antibiotics than their single-cell planktonic counterparts, thereby raising questions about the occurrence of biofilms in the host tissues and their significance in persistence during chemotherapy of tuberculosis. In this article, we present arguments that extracellular M. tuberculosis in necrotizing lesions likely grows as biofilms.