Simultaneous Detection of Mycobacterium tuberculosis and Mycobacterium avium Complex by a Multiplex PCR

Infection disease caused by nontuberculous mycobacteria (NTM) have been increasingly reported and often manifest with the same symptoms of tuberculosis (TB). The identification of the causative agent is fundamental for the determination of an appropriate therapy, since each species of mycobacteria requires a specific treatment. Thus, rapid and accurate tests to identify mycobacteria of medical interest, such as Mycobacterium tuberculosis complex (MTBC) and Mycobacterium avium complex (MAC), are necessary in the clinical routine. The present study evaluated an in-house multiplex PCR to detect, in reference and clinical strains, the genus Mycobacterium and also M. tuberculosis and MAC. To identify the Mycobacterium genus, M. tuberculosis and MAC, it was amplified a fragment of hsp65 gene, esat-6 gene, and the internal transcribed spacer between the 16S and 23S rRNA genes, respectively. In total, 87 mycobacteria strains were used, being 10 reference and 77 clinical strains, previously identified as MTBC (n = 66), M. avium (n = 8) or other NTM specie (n = 13). The hsp65 gene fragment was amplified for all mycobacteria strains evaluated (87/87). This multiplex PCR presented sensitivity of 100% and specificity of 95.2% for M. tuberculosis detection, and sensitivity of 100% and specificity of 100% for MAC detection. The multiplex PCR evaluated is an important tool for the differentiation between M. tuberculosis and NTM, as well as for the identification of MAC, a complex composed by species with high prevalence in the world.