OBJECTIVETo study the genotyping of Bacillus anthracis based on multiple-locus variable-number tandem repeats(VNTR) in the B. anthracis genome.

METHODSWe selected 13 VNTR loci (which cited from published articles) to study 88 strains of B. anthracis isolated from China. The methods used were: (1) Selecting the primers which were at both ends of the tandem repeat locus; (2) Amplifying the sequence of the locus by PCR; (3)cDetecting the PCR products by agarose gel and polyacrylamide electrophoresis; (4)Analyzing the PCR products and computing the molecular weight by analysis software of gel images;(5) Double-checking with sequencing results; (6)Reckoning the repeat numbers and study the VNTRs loci characters.

RESULTS(1) We used multiple-locus variable-number tandem repeat analysis (MLVA) to characterize 88 B. anthracis isolates from diverse geographic locations which were divided into 45 MLVA genotypes and 3 groups through cluster analysis. The genotypes was relative to restricted geographical region. It seemed clear that the multiple isolates from the same anthrax outbreak frequently having identical genotypes. (2)Results from VNTR analysis showed that A16R vaccine strain isolated from China was having the nature of representativeness in the country.

CONCLUSIONAnalysis showed that the VNTR patterns was an appropriate study method for B. anthracis genetic diversity from different geographical areas and different time. Isolates from the same anthrax outbreak had identical