Main challenges in molecular diagnosis of tuberculosis of bovine origin

Bovine tuberculosis is a chronic infectious disease that affects animals and humans and is caused by Mycobacterium bovis. The human disease caused by Mycobacterium bovis is called zoonotic disease and is clinically and pathologically indistinguishable from the disease caused by Mycobacterium tuberculosis. Therefore, the differentiation of mycobacterial species responsible for pulmonary tuberculosis is extremely important, since Mycobacterium bovis is resistant to pyrazinamide, a drug commonly used to treat infection with Mycobacterium tuberculosis. The bacteriological diagnosis of bovine tuberculosis is the gold standard method often used for the identification of Mycobacterium bovis, which combines the isolation of the etiologic agent and the identification of the isolate. However, the culture of mycobacteria can take more than twelve weeks for the outcome and has low sensitivity. Molecular methods such as Polymerase Chain Reaction (PCR) offer an interesting alternative for the classification and identification of these bacteria, quickly and accurately. However, the application of this technique for the diagnosis of bovine tuberculosis still presents limiting aspects, which were presented here and must be considered in the research and improvement of the diagnosis and identification of M. bovis.