[Study on the single nucleotide polymorphism in capsule plasmid gene of Bacillus anthracis in the China isolates]

To study the characteristic of single nucleotide polymorphism (SNP) in capsule plasmid gene of Bacillus anthracis isolated from China.

95 Bacillus anthracis isolates from different sources were selected. 23 SNP sites were amplified by PCR method, sequenced and analyzed by clustering analysis.

95 Bacillus anthracis isolates were divided into 5 groups by cluster analysis. The identified isolates had the same sequence features in 17 sites and different nucleotide sequence in the other 6 sites of the 23 SNP sites. 17.89% (17/95) of the isolates had homologous locus sequences compared with the reference strain Pastuer. 38.95% (37/95) of the isolates had the homologous locus sequences compared with the reference strain Ames Ancestor. The remaining strains were different from those completed sequenced strains. 3 strains missed length of about 80 bp sequence in the PS-34 loci amplified gene fragment in which the tested SNP loci were included. 9 strains were amplified negative at all SNP loci and Bacillus anthracis capsule plasmid genes were missing which was confirmed by capsule plasmid gene-specific primers.

Results through analysis showed that single nucleotide genetic stability and specificity for capsule plasmid gene of Bacillus anthracis did exist in the Chinese isolates. The 6 discriminating SNP sites could be used as indicators in genotyping the Bacillus anthracis.