Fifty-six clinical isolates of Mycobacterium tuberculosis were analyzed by spoligotyping to determine the prevalence of W-Beijing strains. Forty-nine of the 56 isolates belonged to W-Beijing strains and 7 isolates were non-Beijing strains. Comparative two-dimensional gel electrophoresis analysis of protein patterns between the W-Beijing and non-Beijing strains identified a unique protein Rv0927c that is absent in the former but present in the latter and the reference strain M. tuberculosis H37Rv. Compared with 7 non-Beijing clinical isolates and H37Rv, all 49 W-Beijing strains had two characteristic mutations, a deletion of AGC at nucleotide position 421 of Rv0927c gene encoding a putative short dehydrogenase/reductase, causing deletion of serine codon at amino acid position 141 and a -127 G -> A mutation in Rv0927c-pstS3 intergenic region, resulting in failure to express Rv0927c. Western blot analysis indicated that polyclonal antibody raised against H37Rv Rv0927c overexpressed in Escherichia coli reacted with non-Beijing strains and H37Rv but not W-Beijing strains. Characteristic mutations of Rv0927c that are present in W-Beijing strains can be used as a novel genetic marker for rapid molecular typing of M. tuberculosis W-Beijing strains. (c) 2006 Elsevier Masson SAS. All rights reserved.
(8.0+极速模式)