Molecular tools for rapid identification and novel effective therapy against MDRTB/XDRTB infections

Abstract

Tuberculosis (TB) is mainly an intracellular infection of the lung alveolar macrophages, and any anti-TB agent must therefore be active at the macrophage. Among the available therapies, isoniazid and rifampicin are the most effective drugs against susceptible Mycobacterium tuberculosis, but they are ineffective against multidrug-resistant TB (MDRTB) strains. Rates of MDRTB in Portugal are the highest in Western Europe, demanding effective measures for their control. Our application of molecular techniques for the early identification of MDRTB assisted in the reduction of these rates. Further examination revealed that a large number of MDRTB cases were extensively-drug resistant (XDRTB), providing evidence for the urgent need of new and effective anti-MDRTB/XDRTB therapeutic strategies. This review describes in detail: the characteristics of the main M. tuberculosis strains circulating in Portugal; the creation of a Task Force for TB control, based on molecular tools that allow 1-day identification of an MDRTB patient; the usefulness of evaluating the ex vivo activity of anti-tubercular agents against the M. tuberculosis isolated from the patient’s sputum; and the mode of action by which phenothiazines have been shown to promote the killing of intracellular MDRTB/XDRTB by nonkilling macrophages.