[Characteristics of isogenic variants of Bacillus anthracis with various content of virulence plasmids].

AIM: Production and characteristics by main cultural-morphologic and antigenic properties of isogenic variants Bacillus anthracis, that differ by the presence of virulence plasmids.

MATERIALS AND

METHODS

B. anthracis 81/1, 575/122 virulent and B. anthracis STI, 55, Sterne vaccine strains were used in the study. Isogenic variants, that differ by the presence of virulence plasmids, were obtained by temperature elimination of plasmids, as well as during cultivation of anthrax strains in medium with kanamycin. The strains were characterized by cultural-morphologic, biochemical properties. The presence of virulence plasmids was determined by polymerase chain reaction method. Antigenic properties were studied in immune diffusion reaction with growing cultures with sera against protective antigen and S-layer proteins, electrophoresis, immune blotting.

RESULTS

Isogenic variants were produced from virulent strains B. anthracis 81/1, 575/122 and vaccine strains STI, 55, Sterne: mono-plasmid toxin-producing (81/1 R01, 575/122 R01) and capsule-containing (81/1 R02, 575/122 R02), and plasmid-less (81/1 R00, 575/122 R00, STI R00, 55 R00, Sterne R00), that differ by the presence of virulence plasmids. Strains had typical cultural-morphologic properties, differed by biochemical and antigenic properties. Cultural filtrates of toxin-producing strains had protein of anthrax toxin; plasmid-less strains--had proteins, that had molecular masses corresponding to molecular masses of S-layer EA1 and Sap proteins.

CONCLUSION

These strains may be used to study variability and proteomic analysis of anthrax causative agent, as well as for isolation of antigens with the aim of evaluating their immune diagnostic significance.