A EVOLUÇÃO DOS MÉTODOS DIAGNÓSTICOS EM MICOBACTERIOLOGIA

da baciloscopia tradicional ao impacto dos testes rápidos moleculares e do sequenciamento genético na decisão clínica

Abstract

Tuberculosis (TB) has accompanied humanity since antiquity, and over the course of more than 150 years, its diagnosis has evolved from purely clinical criteria to increasingly sophisticated microbiological, radiological, and molecular methods. Sputum smear microscopy, introduced in the 19th century, remains widely used in high-burden countries due to its simplicity and low cost, although it presents limited sensitivity and an inability to differentiate mycobacteria or detect drug resistance. Culture, still considered the gold standard for demonstrating bacillary viability and enabling drug susceptibility testing, has undergone significant advancements with automated liquid media and immunochromatographic tests for rapid species identification; however, it remains underutilized in the Brazilian Unified Health System (SUS).

The recent revolution stems from molecular methods, particularly the Xpert MTB/RIF Ultra and other automated or low-complexity platforms (Truenat, TB-LAMP, LPA), which offer faster and more sensitive diagnosis, alongside the detection of resistance to rifampicin and other drugs. Newer approaches, such as antigen detection assays (LF-LAM) and next-generation sequencing (tNGS, WGS), expand diagnostic and surveillance capabilities, though they are still restricted by costs and the need for specialized infrastructure. Near-point-of-care innovations, such as the MiniDock MTB and the use of tongue swabs, point toward greater decentralization of testing in resource-limited settings. Despite this technological arsenal, TB control remains limited by social determinants and the challenges of accessing quality diagnosis in high-burden scenarios.