Molecular mechanisms of inherent drug resistance in non-tuberculous mycobacteria

Abstract Infections caused by non-tuberculous mycobacteria (NTMs) are substantial clinical problems. The response to therapy is disappointing and the goal for patients with chronic infections is generally to control rather than cure infection. This means extended antibiotic treatment with drugs and associated toxicities that tend to accumulate over time. While there has been considerable investment in developing new antibiotics for the treatment of tuberculosis, caused by the related organism Mycobacterium tuberculosis (Mtb), most of these emergent therapies have little or no activity in NTMs. This has made treatment of the rising number of NTM cases highly problematic. Here we propose to use tools we have recently developed to study NTMs and identify mechanisms to resensitize these pathogens to antibiotics to which they are intrinsically resistant. We will use a new tissue culture model of lung infection together with genetic approaches to find and validate genes and pathways that allow growth inhibition at achievable drug concentrations and/or more rapid killing by existing drugs and advanced antibacterial compounds in Mycobacterium abscessus. We will then explore the underlying biologic mechanisms of sensitization and extend these observations to an even more common cause of human infection, organisms of the Mycobacterium avium complex. Our goal is to determine the therapeutic targets that will best result in bacterial clearance even in the absence of effective host defenses.