Utility of mycobacterial interspersed repetitive unit typing for differentiating Mycobacterium tuberculosis isolates in Wuhan, China

Mycobacterial interspersed repetitive unit (MIRU) typing has been found to allow rapid, reliable, high-throughput genotyping of Mycobacterium tuberculosis, and may represent a feasible approach to study M. tuberculosis molecular epidemiology. To evaluate the use of MIRU typing in discriminating M. tuberculosis strains, isolates from 105 patients in Wuhan City, China, were genotyped by this method as compared to spoligotyping. MIRU typing identified 55 types that defined 21 clusters and 34 unique isolates. The discriminatory power was high [Hunter-Gaston discriminatory index (HGDI), 0.97]. Spoligotyping showed that 86 (81.9%) of 105 isolates belonged to the Beijing family genotype. For Beijing family and non-Beijing strains, the discriminatory power of MIRU was high (HGDI, 0.95 and 0.98, respectively). Among the alleles of the MIRU loci for the Beijing family, only locus 26 was highly discriminative, but for non-Beijing strains, loci 10, 16 and 26 were highly discriminative. MIRU typing is a simple and fast method which may be used for preliminary screening of M. tuberculosis isolates in China.