Comparison of three molecular typing methods to assess genetic diversity for Mycobacterium tuberculosis

This study describes the comparison of three methods for genotyping of Mycobacterium tuberculosis, namely MIRU-VNTR (mycobacterial interspersed repetitive units-variable number of tandem repeats), spoligotyping and, for the first time, MLST (Multilocus Sequence Typing). In order to evaluate the discriminatory power of these methods, a total of 44 M. tuberculosis isolates obtained from sputum specimens of patients from Brazil were genotyped. Among the three methods, MLST showed the lowest discriminatory power compared to the other two techniques. MIRU-VNTR showed better discriminatory power when compared to spoligotyping, however, the combination of both methods provides the greatest level of discrimination and therefore this combination is the most useful genotyping tool to be applied to M. tuberculosis isolates. ► MIRU-VNTR, spoligotyping and MLST were tested for M. tuberculosis. ► In this study, MLST was fully tested for this species for the first time. ► Results indicated that MLST is not a suitable method to differentiate M. tuberculosis. ► MIRU-VNTR showed better discriminatory power when compared to spoligotyping and MLST. ► A combination of MIRU-VNTR and spoligotyping provided best discriminatory power.