Search

A quantitative and qualitative comparison was carried out of Mycobacterium tuberculosis Beijing strains isolated in three remote areas of Japan. A total of 452 strains from Chiba Prefecture, 75 from Yamagata Prefecture, and 315 from Kobe City were analyzed for 24 loci by variable number of tandem repeats typing (24 Beijing -VNTR). All strains were classified in six Beijing subgroups (B SUB ), B1 to B5 and T, based on a minimum spanning tree reconstructed using data of a standard set of 15 VNTR loci. No significant difference was found in the distribution of strains in the B SUB in the three areas, with one exception due to a B5 outbreak in Yamagata, indicating no significant quantitative difference in the B SUB in the three areas ( P < 0.01, Chi -square test). In addition, when strains in each B SUB isolated in the three areas were mixed and standardized index of association ( I A s ) and variance ( Φ PT ) values were calculated, no significant qualitative difference in the B SUB in the three areas was found. These results suggested that the B SUB diverged prior to the introduction of M. tuberculosis Beijing strains into Japan. Differences in the distribution of strains in each B SUB between Japan and continental Asian countries suggested there had been genetic drift in the continental Asian countries in which B4 had been dominant. [ABSTRACT FROM AUTHOR]

The prevalence of the phylogenetic groups of Mycobacterium tuberculosis Beijing genotype has been reported to be similar in different areas of Japan. However, recent reports from rural areas of Japan show a low prevalence of modern Beijing strains, suggesting that the distribution of modern Beijing strains may have changed recently. Therefore, multi-locus variable number of tandem repeats analysis (MLVA) and draft whole genome sequence (DWGS) analysis were carried out to investigate the prevalence of particular genotype strains. Nine hundred and ninety modern Beijing strains were studied using minimum spanning tree (MST) analysis and neighbor-net analysis of MLVA and WGS data. An MST of M. tuberculosis Beijing genotype strains reconstructed from 12 loci-MLVA data showed two large complexes with the J 12 -0006 MLVA pattern. In one of the complexes, strains with the pECT07 pattern produced by 24 loci-MLVA and its SLVs were most prevalent. DWGS analysis was carried out for pECT07 and its SLV strains. Neighbor-net and MST analyses of the DWGS data showed that pECT07 and its SLV strains were grouped in separate clusters. When all the combinations of two of the tested strains were analyzed, MST analysis showed that only 9 (1.7%) of the 528 pairs of tested strains had 5 or less SNPs. The results of this study suggested that pECT07 and its variants were prevalent among M. tuberculosis modern Beijing strains in Chiba Prefecture, but the prevalence of those strains may not have been due to an earlier large-scale latent outbreak. [ABSTRACT FROM AUTHOR]