Latent Tuberculosis: A Promising New Compound to Treat Non-Replicating and Intramacrophagic Mycobacteria

As a biologic reservoir of Mycobacterium tuberculosis (M. tb), one-quarter of the world population is infected with the well-known latent tuberculosis (LTBI). About 5–10% of LTBI patients will progress to active disease in the first years after primary infection and, despite using the recommended treatment, 20% can still reactivate the infection. A new LTBI treatment could minimize adverse effects and antibiotic resistance that can occur when the same drug is used to treat the latent and active disease. New hydrazones were evaluated, and they showed great inhibitory activity against intramacrophagic and non-replicating M. tb, commonly found at this stage of infection, in addition to bactericidal and narrow-spectrum activity. When tested against eukaryotic cells, the hydrazones showed great safety at different exposure times. In vitro, these compounds performed better than isoniazid and could be considered new candidates for LTBI treatment, which may promote greater engagement in its prescription and adherence.