Genotypic analysis of Mycobacterium tuberculosis strains collected from He′nan Province by 24-locus variable-number tandem-repeat typing and spoligotyping

Objective To investigate the genotype of M. tuberculosis in He′nan Province. Methods A total of 668 M. tuberculosis clinical strains collected in difference regions of He′nan Province during 2015 were genotyped by two standard methods, including classical 24-locus mycobacterium interspersed repetitive unit variable-number tandem-repeat (MIRU-VNTR) typing and spoligotyping. Results The 668 isolates were divided into 11 clusters and 35 patterns by spoligotyping. Among the 558 Beijing strains, 546 were typical Beijing strains and the other 12 were atypical Beijing strains. Among the 110 non-Beijing strains, eight were new strains and the remaining 102 non-Beijing strains were divided into 10 families. There were 76 isolates belonging to T family, including 59 of T1 families, 7 of T2 families, and 10 of T3 families. The 668 strains were divided into 550 gene patterns by standard 24-locus VNTR, including 508 un-clustered patterns and 160 clustered into 42 clusters. The largest cluster contained 21 strains, the other clusters contained 2-20 strains. Conclusion Beijing strain is still the most prevalent M. tuberculosis in He′nan Province. Key words: Mycobacterium tuberculosis; 24-locus mycobacterium interspersed repetitive unit-variable number tandem repeat; Spoligotyping