Diagnostic of rifampicin-resistance of Mycobacterium tuberculosis by polymerase chain reaction

The resistance of Mycobacterium tuberculosis to tuberculostatic drugs has emerged as a major public health threat. The resistance to rifampicin which has been attributed to structural changes in RNA polymerase can be considered as a marker for multi-drug-resistance to tuberculosis (MDR-TB). Patients bearing rifampicin-resistant strains have poor diagnosis even with treatment. Conventional culture-based drug sensibility testing can require several weeks due to the growth. In this paper we describe the most common PCR-based methods for detection of mutations that lead to rifampicin resistance, such as Single-Strand Conformation Polymorphism (SSCP), PCR Heteroduplex and INNO-LIPA. Recently, by Low Stringency using a Single Specific Primer (LSSP) assay, it was standardized a protocol that showed to be rapid and sensitive for the detection of mutations in the rpoB gene.